CA2649928C - Improvements in and relating to separating solids and liquids - Google Patents
Improvements in and relating to separating solids and liquids Download PDFInfo
- Publication number
- CA2649928C CA2649928C CA2649928A CA2649928A CA2649928C CA 2649928 C CA2649928 C CA 2649928C CA 2649928 A CA2649928 A CA 2649928A CA 2649928 A CA2649928 A CA 2649928A CA 2649928 C CA2649928 C CA 2649928C
- Authority
- CA
- Canada
- Prior art keywords
- mixture
- water
- mineral matrix
- dispensing
- location
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
- C10G1/04—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by extraction
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B1/00—Preliminary treatment of solid materials or objects to facilitate drying, e.g. mixing or backmixing the materials to be dried with predominantly dry solids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B2200/00—Drying processes and machines for solid materials characterised by the specific requirements of the drying good
- F26B2200/18—Sludges, e.g. sewage, waste, industrial processes, cooling towers
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Molecular Biology (AREA)
- Organic Chemistry (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
A method is provided for at least partially separating a mineral matrix from water, such as tailings from oil sands operations. The method comprises taking the tailings, introducing a flocculent to the tailings, passing the mixture through a mixing stage to give a further mixture and feeding the further mixture to a dispensing conduit provided at a dispensing stage. The further mixture is dispensed at the dispensing stage so that later parts of the mixture are applied over earlier parts of the mixture. A cone of retained material may arise as a result, with at least a part of the water flowing away and being reused. Faster, lower cost dewatering is provided.
Description
IMPROVEMENTS IN AND RELATING TO SEPARATING SOLIDS AND LIQUIDS
The present invention is concerned with improvements in and relating to separating solids and liquids, particularly solids suspended in aqueous media, and more particularly, with thickening of aqueous suspensions arising from processing operations relating to oil sands.
A great variety of situations call for the partial separation of fine solid material from the water in which they are suspended. The appropriate techniques and materials to use vary greatly from situation to situation.
One particularly problematic suspension arises from processing operations relating to bituminous sands, oil sands or tar sands; which terms are used interchangeably herein. The tailings in particular, which include finely divided clay and silica materials, are particularly awkward to address and are commonly known as "oil sand tailings". These tailings arise when the bitumen is extracted from oil sands by a process known as the "hot water process".
The bitumen itself is further processed after the separation and refined to give synthetic crude oil.
The oil sand tailings which arise are hard to filter or de-water due to the presence of very fine clay and the varying composition of such tailings, as a wide variety of clay materials can be present. The clays include kaolinite, montmorillonite and illite.
Filtering, settling or other conventional techniques, such as flocculation, have not worked satisfactorily on such tailings. As a consequence, there is frequent practice of the storage of the tailings as slimes in settling ponds. The enormous scale of the oil sands processing leads to the settling ponds covering many acres of land. The settling ponds also include large quantities of water. These ponds present a variety of potential problems because of their use.
CA2364854 represents a successful approach to dewatering using a combination of a first anionic polymer having a molecular weight of less than 2,000,000 and a charge between 40 and 100%, together with a second anionic polymer having a molecular weight of at least 5,000,000 and a charge of between 1 and 50%.
Even with such approaches, however, there is room for improvement. The present invention has amongst its aims potentially to decrease the time taken to achieve the solid from liquid separation. The present invention has amongst its aims potentially to decrease the cost of the solid from liquid separation. The present invention has amongst its aims potentially to provide the solid from liquid separation in a smaller area per unit volume than previously possible. The present invention has amongst its aims potentially to provide a low capital cost and/or low operating cost system.
According to a first aspect of the invention we provide a method of at least partially separating a mineral matrix from water, the method comprising:
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, the third mixture including a first part that is fed to the dispensing conduit and the third mixture including a second part that is fed to the dispensing conduit;
dispensing the third mixture at the dispensing stage, including dispensing the first part and the second part, the second part being dispensed on to at least a portion of the first part;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
The method may provide a separation of mineral matrix and water which gives a mineral matrix and water mixture which is at least 40% solids by weight, preferably at least 50% solids by weight and more preferably at least 55% by weight.
The method may provide a separation in which a % solids of 72% is reached in a time frame of 3 minutes after the mixture is dispensed. The method may provide or may further provide a separation in which a % solids of 94%, is reached in a time frame of
The present invention is concerned with improvements in and relating to separating solids and liquids, particularly solids suspended in aqueous media, and more particularly, with thickening of aqueous suspensions arising from processing operations relating to oil sands.
A great variety of situations call for the partial separation of fine solid material from the water in which they are suspended. The appropriate techniques and materials to use vary greatly from situation to situation.
One particularly problematic suspension arises from processing operations relating to bituminous sands, oil sands or tar sands; which terms are used interchangeably herein. The tailings in particular, which include finely divided clay and silica materials, are particularly awkward to address and are commonly known as "oil sand tailings". These tailings arise when the bitumen is extracted from oil sands by a process known as the "hot water process".
The bitumen itself is further processed after the separation and refined to give synthetic crude oil.
The oil sand tailings which arise are hard to filter or de-water due to the presence of very fine clay and the varying composition of such tailings, as a wide variety of clay materials can be present. The clays include kaolinite, montmorillonite and illite.
Filtering, settling or other conventional techniques, such as flocculation, have not worked satisfactorily on such tailings. As a consequence, there is frequent practice of the storage of the tailings as slimes in settling ponds. The enormous scale of the oil sands processing leads to the settling ponds covering many acres of land. The settling ponds also include large quantities of water. These ponds present a variety of potential problems because of their use.
CA2364854 represents a successful approach to dewatering using a combination of a first anionic polymer having a molecular weight of less than 2,000,000 and a charge between 40 and 100%, together with a second anionic polymer having a molecular weight of at least 5,000,000 and a charge of between 1 and 50%.
Even with such approaches, however, there is room for improvement. The present invention has amongst its aims potentially to decrease the time taken to achieve the solid from liquid separation. The present invention has amongst its aims potentially to decrease the cost of the solid from liquid separation. The present invention has amongst its aims potentially to provide the solid from liquid separation in a smaller area per unit volume than previously possible. The present invention has amongst its aims potentially to provide a low capital cost and/or low operating cost system.
According to a first aspect of the invention we provide a method of at least partially separating a mineral matrix from water, the method comprising:
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, the third mixture including a first part that is fed to the dispensing conduit and the third mixture including a second part that is fed to the dispensing conduit;
dispensing the third mixture at the dispensing stage, including dispensing the first part and the second part, the second part being dispensed on to at least a portion of the first part;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
The method may provide a separation of mineral matrix and water which gives a mineral matrix and water mixture which is at least 40% solids by weight, preferably at least 50% solids by weight and more preferably at least 55% by weight.
The method may provide a separation in which a % solids of 72% is reached in a time frame of 3 minutes after the mixture is dispensed. The method may provide or may further provide a separation in which a % solids of 94%, is reached in a time frame of
2 weeks after the mixture is dispensed.
The mineral matrix source may be a process stream from a process plant, particularly a process plant separating hydrocarbon from a mineral matrix. The mineral matrix source may be a direct feed from the process plant or may be via an intermediate storage location and/or intermediate treatment location. The mineral matrix source may be a hydrocyclone, particularly the underflow therefrom. The mineral matrix source may be a thickener, particularly the underflow therefrom.
The mineral matrix may include one or more clays and/or one or more sands. The mineral matrix may include one or more of kaolinite, montmorillonite and illite.
The water may be water added to the mineral matrix as part of a process preceding the method and/or be water occurring with the mineral matrix.
The mineral matrix and water mixture may be greater than 30% solids, for instance greater than 40% solids or even greater than 50% solids.
The mineral matrix may have greater than 20% of the material less than 44 microns, preferably greater than 30% less than 44 microns, more preferably greater than 40% less than 44 microns. The mineral matrix may have greater than 10% of the material less than 20 microns, potentially greater than 30% less than 20 microns, preferably greater than 50% less than 20 microns, more preferably greater than 60% less than 20 microns and ideally greater than 80% less than 20 microns.
The mineral matrix and water mixture may be pumped past the first location.
The first location may be a junction of a conduit carrying the mineral matrix and water mixture and a conduit carrying another stream.
The another stream may include the flocculent.
The flocculent may be prepared at the flocculent source or may be prepared remotely and brought to the flocculent source.
The flocculent may have an average molecular weight of at least 5,000,000, preferably at least 8,000,000, more preferably at least 12,000,000 and still more preferably at least 17,000,000. The flocculent may have an average molecular weight of 18,000,000 +/- 10%.
The flocculent may have a charge of between 1 and 50%, preferably between 3 and 50% and more preferably between 5 and 50%. The flocculent may have a charge of 20% +/-10% of that level.
The flocculent is preferably water soluble. The flocculent may be an anionic polymer.
The anionic polymer may be linear or branched. Preferably, the anionic polymer is produced by polymerising one or more anionic monomers with one or more non-ionic monomers. The proportion of anionic monomers to non-ionic monomers can be used to control the percentage charge.
The mineral matrix source may be a process stream from a process plant, particularly a process plant separating hydrocarbon from a mineral matrix. The mineral matrix source may be a direct feed from the process plant or may be via an intermediate storage location and/or intermediate treatment location. The mineral matrix source may be a hydrocyclone, particularly the underflow therefrom. The mineral matrix source may be a thickener, particularly the underflow therefrom.
The mineral matrix may include one or more clays and/or one or more sands. The mineral matrix may include one or more of kaolinite, montmorillonite and illite.
The water may be water added to the mineral matrix as part of a process preceding the method and/or be water occurring with the mineral matrix.
The mineral matrix and water mixture may be greater than 30% solids, for instance greater than 40% solids or even greater than 50% solids.
The mineral matrix may have greater than 20% of the material less than 44 microns, preferably greater than 30% less than 44 microns, more preferably greater than 40% less than 44 microns. The mineral matrix may have greater than 10% of the material less than 20 microns, potentially greater than 30% less than 20 microns, preferably greater than 50% less than 20 microns, more preferably greater than 60% less than 20 microns and ideally greater than 80% less than 20 microns.
The mineral matrix and water mixture may be pumped past the first location.
The first location may be a junction of a conduit carrying the mineral matrix and water mixture and a conduit carrying another stream.
The another stream may include the flocculent.
The flocculent may be prepared at the flocculent source or may be prepared remotely and brought to the flocculent source.
The flocculent may have an average molecular weight of at least 5,000,000, preferably at least 8,000,000, more preferably at least 12,000,000 and still more preferably at least 17,000,000. The flocculent may have an average molecular weight of 18,000,000 +/- 10%.
The flocculent may have a charge of between 1 and 50%, preferably between 3 and 50% and more preferably between 5 and 50%. The flocculent may have a charge of 20% +/-10% of that level.
The flocculent is preferably water soluble. The flocculent may be an anionic polymer.
The anionic polymer may be linear or branched. Preferably, the anionic polymer is produced by polymerising one or more anionic monomers with one or more non-ionic monomers. The proportion of anionic monomers to non-ionic monomers can be used to control the percentage charge.
3 The dosage of the flocculent used may be 100 to 600g/tonne of mineral matrix in the mixture, preferable depending upon the clay content of the mineral matrix. The dosage of the flocculent used may be 200 to 500g/tonne of mineral matrix in the mixture, preferable depending upon the clay content of the mineral matrix. The dosage of the flocculent used may be 250 to 450g/tonne of mineral matrix in the mixture, preferable depending upon the clay content of the mineral matrix.
The flocculent may be provided in the flocculent source at a concentration of 1.5wt%.
The flocculent may be a mixture of flocculents. The mixture may be provided by blending flocculents together, preferably prior to addition to the water stream.
The another stream may also include water. The water may be dilution water for mixing with the mixture to give the second mixture.
The dilution water may be added from outside the process circuit of the method, for instance make up water or fresh water. Preferably the dilution water is water extracted from the further location, for instance a tailings pond, and most preferably decant water therefrom.
The dilution water may be pumped from the further location. The dilution water may pass a second location, for instance a second junction. Preferably the flocculent is added to the dilution water at the second location. Mixing of the flocculent and dilution water may occur between the second location and the first location.
The another stream, preferably containing the dilution water and/or flocculent, may mix with the mixture between the first location and the mixing location to give the second mixture.
Preferably the majority of the mixing of the dilution water and flocculent and/or flocculent and mixture and/or mixture and dilution water occur in the mixing stage.
The mixing stage is preferably a static mixer. The mixing stage may have no moving parts to the mixer. The mixing stage may have one or more, preferably greater than 4, static plates. The plates may be inclined relative to the axis of the static mixer and/or relative to the radius of the mixer perpendicular to its axis. The mixer may provide a geometric flow pattern within it. The static mixer may provide non-random mixing. The cross-sectional area of the static mixer, perpendicular to the direction of flow through the static mixer, is preferably greater than the cross-sectional area of the conduit leading to the static mixer and/or cross-sectional area of the conduit leading from the static mixer.
The flocculent may be provided in the flocculent source at a concentration of 1.5wt%.
The flocculent may be a mixture of flocculents. The mixture may be provided by blending flocculents together, preferably prior to addition to the water stream.
The another stream may also include water. The water may be dilution water for mixing with the mixture to give the second mixture.
The dilution water may be added from outside the process circuit of the method, for instance make up water or fresh water. Preferably the dilution water is water extracted from the further location, for instance a tailings pond, and most preferably decant water therefrom.
The dilution water may be pumped from the further location. The dilution water may pass a second location, for instance a second junction. Preferably the flocculent is added to the dilution water at the second location. Mixing of the flocculent and dilution water may occur between the second location and the first location.
The another stream, preferably containing the dilution water and/or flocculent, may mix with the mixture between the first location and the mixing location to give the second mixture.
Preferably the majority of the mixing of the dilution water and flocculent and/or flocculent and mixture and/or mixture and dilution water occur in the mixing stage.
The mixing stage is preferably a static mixer. The mixing stage may have no moving parts to the mixer. The mixing stage may have one or more, preferably greater than 4, static plates. The plates may be inclined relative to the axis of the static mixer and/or relative to the radius of the mixer perpendicular to its axis. The mixer may provide a geometric flow pattern within it. The static mixer may provide non-random mixing. The cross-sectional area of the static mixer, perpendicular to the direction of flow through the static mixer, is preferably greater than the cross-sectional area of the conduit leading to the static mixer and/or cross-sectional area of the conduit leading from the static mixer.
4 The mixing stage is preferably a low shear rate mixing stage. The mixing stage may provide a shear rate of less than 100s-1, preferably less than 50s-', more preferably 15s-1 and potentially even less than 10s-1.
The second and/or third mixture may have a solids content of less than 20%.
The second and/or third mixture may have a solids content of less than 18%. The second and/or third mixture may have a solids content of greater than 10%. The second and/or third mixture may have a solids content of greater than 12%.
The third mixture may be conveyed to the dispensing conduit along one or more intermediate conduits. A first intermediate conduit may be connected to the mixing stage. A
first intermediate conduit may be provided which is substantially horizontal.
A first intermediate conduit may be used to connect the mixing stage to a second intermediate stage.
The second intermediate conduit may connect the first intermediate conduit to the dispensing conduit. The second intermediate conduit may be curved, for instance to provide a transition to the vertical for the dispensing conduit. A transition through substantially 90 may be provided.
One or more conduits may be provided with access points, for instance for removing blockages and/or for introducing backwash water.
The third mixture may be conveyed to a position on a drainage surface, for instance a position at least 100m from the edge thereof. The position may be the centre of a drainage surface.
The third mixture may be conveyed to the dispensing conduit along one or more conduits provided wholly or partially underground, for instance under a drainage surface.
The dispensing conduit may be at least 50m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 75m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 100m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 125m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 150m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture.
The dispensing conduit may have a height, relative to the adjacent part of the drainage surface and/or relative to the bottom of the stack of dispensed third material of more than 25m, preferably more than 50m, more preferably more than 100m and ideally more than 140m.
A plurality of through apertures may be provided along the length of the dispensing conduit. The through apertures may be evenly distributed on the dispensing conduit between the first aperture and the last aperture. A through aperture may be between 2cm and 100cm away from the next aperture along the dispensing conduit, axially. A through aperture may be between 10cm and 75cm away from the next aperture along the dispensing conduit, axially. A
through aperture may be between 15cm and 40cm away from the next aperture along the dispensing conduit, axially. The through apertures are preferably provided around the circumference of the dispensing conduit, preferably evenly distributed circumferentially.
Preferably the time period between the first part of the third mixture leaving the mixing stage and being dispensed from the dispensing conduit is less than 15 seconds, preferably less than 11 seconds and ideally less than 8 seconds.
Preferably the time period between the first part of the second mixture entering the mixing stage and being dispensed from the dispensing conduit is less than 15 seconds, preferably less than 11 seconds and ideally less than 8 seconds.
The third mixture may be dispensed so that the third mixture flows over the outside surface of the already retained mineral matrix. The water may flow down the outside layer of the retained mineral matrix. The mineral matrix may flow down the retained mineral matrix until assuming a position in which it joins the retained mineral matrix. The retained mineral matrix may build to form a cone of material. The retained mineral matrix may build with the greatest height adjacent the dispensing conduit and/or lowest height at the periphery of the retained material.
Preferably the angle of repose of the retained mineral matrix after dispensing is greater than 30 , more preferably greater than 35 still more preferably greater than 40 and ideally greater than 42 .
A given volume of retained mineral matrix may have a solids content of at least 55%
minutes after being dispensed, more preferably at least 60%. A given volume of retained mineral matrix may have a solids content of at least 60% 30 minutes after being dispensed, more preferably at least 65%. A given volume of retained mineral matrix may have a solids content of at least 68% 24 hours after being dispensed, more preferably at least 73%. A given volume of retained mineral matrix may have a solids content of at least 93% 6 months after being dispensed, more preferably at least 96%.
Preferably the aperture or apertures having the greatest flow rate of the third mixture move up the dispensing conduit as the height of the retained mineral matrix increases.
Preferably the part of the water which flows away from the dispensing location flows to a container, for instance a tailings pond. Preferably water decanted from the container provides the dilution water for a later part of the mineral matrix and water mixture separation process.
The dispensing stage may include a drainage surface. The drainage surface may be impermeable to water. The drainage surface preferably controls the direction of water flow away from the dispensing stage. The drainage surface and/or one or more further elements may control the flow of water from the dispensing location to the further location.
The flow of water away from the dispensing location may carry with it mineral matrix material.
The further location may be a container. The container may be a volume surrounded or enclosed by one or more water restraining structures, such as one or more walls and a base.
The container may be impermeable, or at least substantially impermeable, to water flow. The walls may be of earth, soil or the like. The container may be formed by the extraction of mineral matrix. The container may be a tailings pond.
The further location may provide for the further separation of the part of the mineral mineral matrix which enters the further location from the water which enters the further location. The further separation may be a settling process. The further separation may be achieved by the descent of the mineral matrix material within the volume of mineral matrix and water. The further separation may result in a low % solids upper level, for instance a decant.
Water may be withdrawn from the further location, particularly from the upper level thereof. Preferably water withdrawn from the further location is used in a mineral extraction process, particularly the extraction of hydrocarbon from a mineral matrix.
Most preferably the water is recycled to the process that generated the mineral matrix and water mixture. The present invention is beneficial in reducing the amount of make up water for the process plant which has to be obtained from fresh water sources, by increasing the amount returned and speed by which the water is returned.
The withdrawn water may be further treated before return to the process plant.
The further treatment may reduce the solids content of the water. A further polymer, for instance a flocculent, may be added to provide the further treatment, but it is preferred that the flocculent added at the first location is used, without further addition. The flocculent added at the first location and/or one or more further reagents may provide for the softening of water returned to the process plant.
The supply of mineral matrix and water mixture to the process may be stopped after the retained mineral matrix reaches a given height compared with the height of the dispensing conduit and/or relative to its own base. More preferably, the supply of mineral matrix and water mixture is diverted to another dispensing location, most preferably a different dispensing conduit, after the retained mineral matrix reaches a given height compared with the height of the dispensing conduit and/or relative to its own base.
The given height may be greater than 90% of the height of the dispensing location.
After the end of the supply of mineral matrix and water mixture to a dispensing location, a different mineral matrix and water mixture may be provided to that dispensing location. The mineral matrix may be coarser then the mineral matrix originally supplied. The different mineral matrix may be used to cap the retained mineral matrix material. The mineral matrix provided for the cap may be less susceptible to becoming airborne than the original mineral matrix. The different mineral matrix and water mixture may be supplied through the dispensing conduit. The different mineral matrix and water mixture may be applied to the retained mineral matrix externally, for instance by spraying. A
different material may be applied to the retained mineral matrix once the dispensing of the mineral matrix has ceased and/or to cap the retained material. The different material may be a polymer. The different material may be provided on the outside of the retained mineral matrix and/or mingle therewith.
The retained mineral matrix may be capped with a water impermeable material.
The retained mineral matrix may be capped with a vapour permeable material.
The retained mineral matrix or capped retained material matrix may decrease in water content after having been dispensed for 24 hours and/or after capping. The decrease may be to water draining from the retained mineral matrix and/or water evaporating from the retained mineral matrix.
The retained mineral matrix may be kept in the dispensed form for more than 1 week, more than 1 month or even more then 4 months. The retained mineral matrix may remain at the location after the period for which it is stored in its dispensed or capped form. The retained mineral matrix may be reduced in height and/or moved to a configuration having a more level height across its extent, after the stored period. The retained mineral matrix may be moved to another location after the stored period.
The mineral matrix source and/or first location and/or mixing stage and/or flocculent source and/or dilution water conduit may be connectable to a plurality of dispensing conduits.
Preferably they are so connected to only one dispensing conduit at a time, with a mechanism for varying the dispensing conduit connected. Preferably the dispensing conduit connected is changed when a height of retained mineral matrix occurs for a given dispensing conduit.
An array comprising one or more mineral matrix sources and/or one or more flocculent sources and/or one or more dilution water sources and/or one or more further locations may be provided, together with a plurality of dispensing conduits.
The first aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
According to a second aspect of the invention we provide apparatus for obtaining at least a partial separation of a mineral matrix from water, the apparatus including:
a mineral matrix and water conduit connected to a first location;
a flocculent conduit connected directly or indirectly to the first location;
a mixing stage connected to the first location;
a dispensing conduit connected to the mixing stage;
a plurality of aperture provided in the dispensing conduit;
a drainage surface provided below the dispensing conduit;
a further location connected to the drainage surface.
The second aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
According to a third aspect of the invention we provide a kit of parts, the kit comprising one or more of:
a mineral matrix and water conduit connected to a first location;
a flocculent conduit connected directly or indirectly to the first location;
a mixing stage connected to the first location;
a dispensing conduit connected to the mixing stage;
a plurality of aperture provided in the dispensing conduit;
a drainage surface provided below the dispensing conduit;
a further location connected to the drainage surface;
The third aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
According to a fourth aspect of the invention, we provide a method of separating hydrocarbon from an hydrocarbon containing mineral matrix, the method including the provision of a mixture of the hydrocarbon containing mineral matrix and water, passing the mixture to a separation stage, the mixture being at at least 25 C in the separation stage, at least a part of the hydrocarbon passing to a first process stream and at least a part of the water and mineral matrix passing to a second process stream, the second process stream or one or more further process streams derived therefrom being processed to effect a separation of the mineral matrix from the water, the separation including a method of at least partially separating a mineral matrix from water, that method comprising:
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, the third mixture including a first part that is fed to the dispensing conduit and the third mixture including a second part that is fed to the dispensing conduit;
dispensing the third mixture at the dispensing stage, including dispensing the first part and the second part, the second part being dispensed on to at least a portion of the first part;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
The hydrocarbon may be present together with the hydrocarbon containing mineral matrix by virtue of the hydrocarbon being in the interstices and/or gaps and/or pores of the mineral matrix. The hydrocarbon containing mineral matrix, may be a sand and/or a clay incorporating matrices, such as bituminous sands, oil sands or tar sands.
Preferably the mixture is at at least 70 C in the separation stage.
Preferably the mixture is contacted with air in a primary separation stage.
The fourth aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
Various embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:
Figure 1 is an illustration of apparatus according to the invention, before use commences;
Figure 2 is an illustration of the apparatus of Figure 1 after use has started;
Figure 3 is an illustration of the apparatus of Figure 1 and Figure 2, towards the end of use;
Figure 4 is a plan view of an array of apparatus according to the invention.
The methods and apparatus of the present invention are particularly suited to the processing of tailings from bituminous sand, oil sand or tar sand processing, but have application in other solid from liquid separations, particularly those having a high and/or variable clay content.
Tar sands, bituminous sands or oil sands are found in various locations throughout the world, and are increasingly being processed to extract their hydrocarbon content for subsequent processing and refining to give oil. At present, there is significant commercial exploitation of such oil sands in the Athabasca district of the Province of Alberta, Canada.
Such materials may contain between 5 and 20% hydrocarbon, between 1 and 10%
water and between 70 and 90% mineral matrix, substantially all inorganic solids. The mineral matrix is generally formed of a combination of clays, such as kaolinite, montmorillonite and illite, and frequently also include sands.
In the hot water process, hot water (with or without caustic soda) is added to the tar sand to form a slurry. A subsequent separation is provided, at elevated temperatures, frequently using aeration. The mineral matrix mainly reports to the tailings from this process.
However, a significant middling stream also exists which includes a mixture of hydrocarbon and finer parts of the mineral matrix.
The middling stream is generally processed further to extract further hydrocarbon from it and generates a further tailing stream consisting of fine clay, sand and other material.
This stream too is of considerable volume. A plant producing 150,000 barrels of oil a day can produce 200,000 gallons a minute of such a stream.
Other streams also exist, particularly from the solvent extraction processes and these too are difficult to address in terms of the tailings.
If successfully processed to remove a significant fraction of the water content, then the storage volume occupied and the pollution risk posed can be considerably reduced. The enormous amounts of tailings involve mean that any tailings treatment processing is a very cost sensitive step.
Figure 1 provides a schematic illustration of the apparatus used in an embodiment of the invention, in the configuration before processing of the tailings commences.
A drainage surface 1 is created on the edge of a tailings pond 3. The drainage surface 1 is inclined towards the tailings pond 3 to promote the flow of water reaching the drainage surface 1 towards and into the tailings pond 3. An angle of 2 or 3 degrees is sufficient for this purpose. By making the drainage surface 1 impermeable, or at least substantially impermeable, control over water passing through the drainage surface 1 and into the ground 5 below can be exercised.
An alternative drainage surface can be provided which is flat or even inclined away from the pond, with flow of water towards the pond occurring when the water level builds up on the drainage surface and overflows to the tailings pond.
The tailings pond 3 can be a new pond or an existing pond on whose edge the drainage surface 1 is provided. The function of the pond 3 is described in more detail later.
Leading from the tailings pond 3 is decant outlet pipe 7. This decant outlet pipe 7 is provided with a pump 8 and a first junction 9 where it joins a flocculent feed pipe 11. The flocculent feed pipe 11 is connected to a flocculent source 12.
The decant outlet pipe 7 is also provided with a second junction 13 where it joins a tailings inlet pipe 15. The tailings inlet pipe 15 is connected to a tailings source 16.
The tailings inlet pipe 15 connects to a static mixer 17 and then passes to the mixture pipe 18 which extends to the centre 19 of the drainage surface 3 in a generally horizontal configuration. A curved transition section 21 then changes the orientation to a generally vertical configuration for the tailings dispensing pipe 23. The mixing pipe 18 may have a length at least 125% of the height of the tailings dispensing pipe 23.
The tailings dispensing pipe 23 has a height of around 100 to 150m. The tailings dispensing pipe 23 is provided with a series of through apertures 25 provided at various positions along its height. Apertures may be provided at intervals of 15 to 40 cm.
In operation, the flocculent source 12 is provided with the flocculent or flocculent mixture intended for use. The flocculent source 12 can be supplied with flocculent prepared at a remote location and conveyed to the flocculent source 12 for loading there into, ready for use. The flocculent source 12 may include the flocculent preparation function, however. For instance, dried flocculent may be stored at the source 12 and be made up continuously or in batches to provide the flocculent for use.
An example of a flocculent useful in this process and apparatus is AF306HH.
AF306HH is an anionic polymer having a charge of 20mol% and an average molecular weight, AMW, of 18,000,000. The dosage of the flocculent may be 300 to 400g/tonne of tailings depending upon the clay content. The flocculent may be provided in the flocculent source 12 at a concentration of 1.5wt%.
A source of water is connected to the decant outlet pipe 7. This may be decant water 27 from the tailings pond 3 where that pond 3 is already in operation. If such decant water 27 is not initially available, then a water source 29 may be connected to the apparatus. Once the decant water 27 is available, it is the preferred water source for the decant outlet pipe 7.
When decant water 27 is used, the water will already contain some flocculent and so reuse that.
A tailings source 16 is connected to the tailings inlet pipe 15. This may be the overflow stream from a previous solid/liquid separation or thickening stage, for instance a hydrocyclone. A typical tailings source 16 may contain material of greater than 50% <44 microns.
The tailings dispensing pipe 23 and/or one or more of the other pipes may be provided with access locations in case of blockage. For instance, a sealable aperture may be provided in the base of the tailings dispensing pipe 23 to allow the column of mixture 34 therein to drain out on to the drainage surface 1. Back washing facilities may also be provided.
When processing starts, flocculent 30 is dispensed from the flocculent source 12, as a concentrated flocculent, into the water 27 in the decant outlet pipe 7 at first junction 9.
Limited mixing of the flocculent 30 and water 27 occurs at the first junction 9 and during the fluid flow to the second junction 13.
Tailings 32 from the tailings source 16 are passed along the tailings inlet pipe 16 to the second junction 13. Limited mixing of the tailings 32, decant water 27 and flocculent 30 occurs at the second junction 13 and during the flow to the static mixer 17.
The static mixer 17 can be provided in a variety of formats. The absence of rotating or other moving parts in the static mixer 17 means that there are no high shear locations within the mixer. A series of stationary guide plates 33 within the static mixer 17 give the systematic radial mixing of the materials flowing there through. A geometric flow pattern is preferred to avoid any random element to the mixing. Very through mixing in a very short distance is achieved. The mixing energy comes from a very small pressure drop across the static mixer 17. The effectiveness of the mixing is very useful in ensuring the minimum dose flocculent 30 needs to be used. There is no need to overdose so as to ensure all parts receive a minimum dose.
Once in the static mixer 17 the majority of the mixing of the tailings 32, decant water 27 and flocculent 30 occurs to provide the mixture 34. The provision of the static mixer 17 ensures thorough mixing, but in a low shear manner. The low shear conditions prevent the break up of the initial flocs as they form in the mixture 34. The addition of the decant water 27 recycles some of the flocculent and provides the appropriate % solids to the mixture 34 for good mixing, subsequent flocculation and whilst allowing flow through the apparatus. A
figure of approximately 15% solids is a good mark for the mixture 34 to attain.
Following the static mixer 17, the mixture 34 passes along the mixture pipe 18 for the necessary distance, 100m or so, to reach the centre 19 of the drainage surface 1. The mixture 34 then passes through the transition section 21 and up the tailings dispensing pipe 23. The flow passes up the tailings dispensing pipe 23 until the through apertures 25 are reached. The mixture 34 is able to flow out of the through apertures 25 into the space around the tailings dispensing pipe 23.
By the time of its passage through the apertures 25, the mixture 34 is heavily flocculated. Outside of the tailings dispensing pipe 23 this results in the water quickly decanting from the flocs. The flocs settle under gravity around the tailings dispensing pipe 23 and build up into a cone 60. The water 62 flows downhill and hence under the control of the drainage surface 1, into the tailings pond 3.
Within the tailings pond 3, further settling of ultra fine solids from the water may occur. This gives the decant water 27 in the upper layer of the tailings pond and that decant water can be reused via decant outlet pipe 7.
The solid/liquid mixture within the tailings pond 3 may be subjected to further treatment to promote further solid/liquid separation. Whilst part of the decant water 27 may be used in the above process, other water may be decanted from the tailings pond 3 for discharge to water courses and/or for reuse in the process plant, for instance in the "hot water" process.
Figure 2 illustrates the apparatus of Figure 1, part way through a processing cycle.
Continued flow of the mixture 34 into the tailings dispensing pipe 23 has resulted in the cone 60 building up around the tailings dispensing pipe 23. As lower apertures 25 are effectively blocked by the cone 60 building up, the majority of the flow of the mixture 34 out of the tailings dispensing pipe 23 occurs through higher and higher apertures 25. The cone 60 is formed of the flocs and is of a paste like consistency. The cone has an angle of repose, A, in excess of 40 . As the height of the cone 60 builds up, the mass of the cone 60 increasingly compresses the cone material and increases the dewatering.
Figure 3 illustrates the apparatus of Figure 1 and Figure 2, towards the end of a process cycle. The cone 60 has now nearly reached the full height of the tailings dispensing pipe 23, a height of 130m or more. A capping material 70 is now provided so as to coat the external surface of the cone 60. The capping material 70 is intended to prevent dry material on the surface of the cone 60 turning to dust and becoming airborne. A number of ways for providing the capping material 70 exist.
The capping material may be provided by flow of the capping material 70 up the tailings dispensing pipe 25 and down over the outside of the cone 60. This can be achieved by changing the material entering the apparatus from the tailings source 16.
For instance, coarser tailings of a size which won't become airborne could be introduced. In an similar manner, a different source location 80 could be connected instead of the tailings source 16, with that different source location 80 providing the coarser tailings.
A further alternative, not shown, would be to apply the capping material 70 from around the cone 60, rather than up through the tailings dispensing pipe 23.
For instance, the capping material 70 could be sprayed onto the cone 60. Polymer caps 70 may be used for this purpose.
Once capped with the capping material 70, the cone 60 can be left for a period of time.
Further dewatering may occur during this time. The cone 60 may simply be left in this state to provide storage of the dewatered material. Storage in this form, a cone of highly dewatered material takes up far less space than storage as a lower solids content material in relatively shallow tailings ponds or as slurries allowed to spread over large slopes and with a low depth only.
When one unit of apparatus of the above type has finished being loaded with the fine tailings material, the flow of the tailings 32, decant water 27 and flocculent 30 can be switched to a different, but equivalent unit of apparatus. These different units may be radially positioned around a common flocculent source 12, static mixer 17 etc, as shown in Figure 4, to provide an array. As shown, first unit Q and second unit R have been finished and have reached there full heights. Water from these continues to flow over drainage surface 1 which leads to channel C and hence to tailings pond 3. The third unit S has just started building up and so the cone 60 is small in diameter and height. The forth unit T has not started use. Flow to a unit is controlled by valve system V. A given process plant may have one or more such arrays available to it.
After dewatering has been completed to the desired degree, it is possible to remove the cone 60 of dewatered material and make use of it and/or store it at another location. This may result in the material being removed from around the tailings dispensing pipe 23 and the unit being reused for a fresh batch of material to dewater. The provision of the apparatus, however, is relatively cheap and so the apparatus can be discarded and/or demolished as part of the dismantling of the cone 60. The accessibility of the flocculent source 12 allows for the recovery of the apparatus there and the low cost of the PVC pipes used for the decant outlet pipe 7, tailings inlet pipe 15, mixture pipe18, transition section 21 and tailings dispensing pipe 23 allow them to be discarded.
The speed of dewatering and the extent of dewatering are higher than in the prior art.
This means that the site used is far more quickly made available for reuse or returning to the environment, than with tailings ponds or the like. The water in the tailings is also more quickly made available to the process plant once more. This reduces the overall water inventory required of the plant and may even allow heat in the water to effectively be recovered to the plant by the prompt return of the water, rather than the loss of that heat to the environment because the water sits for long periods during the dewatering.
The apparatus and method results in a cone of dewatered tailings at a higher density than is achieved using prior art approaches, such as tailings pond settling, mechanical thickeners etc. The cost of the processing is also lower than with prior art approaches, in terms of hardware costs and reagent costs when compared with centrifuges, and in terms of reagent costs when compared with tailings ponds.
The second and/or third mixture may have a solids content of less than 20%.
The second and/or third mixture may have a solids content of less than 18%. The second and/or third mixture may have a solids content of greater than 10%. The second and/or third mixture may have a solids content of greater than 12%.
The third mixture may be conveyed to the dispensing conduit along one or more intermediate conduits. A first intermediate conduit may be connected to the mixing stage. A
first intermediate conduit may be provided which is substantially horizontal.
A first intermediate conduit may be used to connect the mixing stage to a second intermediate stage.
The second intermediate conduit may connect the first intermediate conduit to the dispensing conduit. The second intermediate conduit may be curved, for instance to provide a transition to the vertical for the dispensing conduit. A transition through substantially 90 may be provided.
One or more conduits may be provided with access points, for instance for removing blockages and/or for introducing backwash water.
The third mixture may be conveyed to a position on a drainage surface, for instance a position at least 100m from the edge thereof. The position may be the centre of a drainage surface.
The third mixture may be conveyed to the dispensing conduit along one or more conduits provided wholly or partially underground, for instance under a drainage surface.
The dispensing conduit may be at least 50m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 75m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 100m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 125m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture. The dispensing conduit may be at least 150m from the nearest edge of the draining surface and/or the mixing stage and/or the stacking area for the dispensed third mixture.
The dispensing conduit may have a height, relative to the adjacent part of the drainage surface and/or relative to the bottom of the stack of dispensed third material of more than 25m, preferably more than 50m, more preferably more than 100m and ideally more than 140m.
A plurality of through apertures may be provided along the length of the dispensing conduit. The through apertures may be evenly distributed on the dispensing conduit between the first aperture and the last aperture. A through aperture may be between 2cm and 100cm away from the next aperture along the dispensing conduit, axially. A through aperture may be between 10cm and 75cm away from the next aperture along the dispensing conduit, axially. A
through aperture may be between 15cm and 40cm away from the next aperture along the dispensing conduit, axially. The through apertures are preferably provided around the circumference of the dispensing conduit, preferably evenly distributed circumferentially.
Preferably the time period between the first part of the third mixture leaving the mixing stage and being dispensed from the dispensing conduit is less than 15 seconds, preferably less than 11 seconds and ideally less than 8 seconds.
Preferably the time period between the first part of the second mixture entering the mixing stage and being dispensed from the dispensing conduit is less than 15 seconds, preferably less than 11 seconds and ideally less than 8 seconds.
The third mixture may be dispensed so that the third mixture flows over the outside surface of the already retained mineral matrix. The water may flow down the outside layer of the retained mineral matrix. The mineral matrix may flow down the retained mineral matrix until assuming a position in which it joins the retained mineral matrix. The retained mineral matrix may build to form a cone of material. The retained mineral matrix may build with the greatest height adjacent the dispensing conduit and/or lowest height at the periphery of the retained material.
Preferably the angle of repose of the retained mineral matrix after dispensing is greater than 30 , more preferably greater than 35 still more preferably greater than 40 and ideally greater than 42 .
A given volume of retained mineral matrix may have a solids content of at least 55%
minutes after being dispensed, more preferably at least 60%. A given volume of retained mineral matrix may have a solids content of at least 60% 30 minutes after being dispensed, more preferably at least 65%. A given volume of retained mineral matrix may have a solids content of at least 68% 24 hours after being dispensed, more preferably at least 73%. A given volume of retained mineral matrix may have a solids content of at least 93% 6 months after being dispensed, more preferably at least 96%.
Preferably the aperture or apertures having the greatest flow rate of the third mixture move up the dispensing conduit as the height of the retained mineral matrix increases.
Preferably the part of the water which flows away from the dispensing location flows to a container, for instance a tailings pond. Preferably water decanted from the container provides the dilution water for a later part of the mineral matrix and water mixture separation process.
The dispensing stage may include a drainage surface. The drainage surface may be impermeable to water. The drainage surface preferably controls the direction of water flow away from the dispensing stage. The drainage surface and/or one or more further elements may control the flow of water from the dispensing location to the further location.
The flow of water away from the dispensing location may carry with it mineral matrix material.
The further location may be a container. The container may be a volume surrounded or enclosed by one or more water restraining structures, such as one or more walls and a base.
The container may be impermeable, or at least substantially impermeable, to water flow. The walls may be of earth, soil or the like. The container may be formed by the extraction of mineral matrix. The container may be a tailings pond.
The further location may provide for the further separation of the part of the mineral mineral matrix which enters the further location from the water which enters the further location. The further separation may be a settling process. The further separation may be achieved by the descent of the mineral matrix material within the volume of mineral matrix and water. The further separation may result in a low % solids upper level, for instance a decant.
Water may be withdrawn from the further location, particularly from the upper level thereof. Preferably water withdrawn from the further location is used in a mineral extraction process, particularly the extraction of hydrocarbon from a mineral matrix.
Most preferably the water is recycled to the process that generated the mineral matrix and water mixture. The present invention is beneficial in reducing the amount of make up water for the process plant which has to be obtained from fresh water sources, by increasing the amount returned and speed by which the water is returned.
The withdrawn water may be further treated before return to the process plant.
The further treatment may reduce the solids content of the water. A further polymer, for instance a flocculent, may be added to provide the further treatment, but it is preferred that the flocculent added at the first location is used, without further addition. The flocculent added at the first location and/or one or more further reagents may provide for the softening of water returned to the process plant.
The supply of mineral matrix and water mixture to the process may be stopped after the retained mineral matrix reaches a given height compared with the height of the dispensing conduit and/or relative to its own base. More preferably, the supply of mineral matrix and water mixture is diverted to another dispensing location, most preferably a different dispensing conduit, after the retained mineral matrix reaches a given height compared with the height of the dispensing conduit and/or relative to its own base.
The given height may be greater than 90% of the height of the dispensing location.
After the end of the supply of mineral matrix and water mixture to a dispensing location, a different mineral matrix and water mixture may be provided to that dispensing location. The mineral matrix may be coarser then the mineral matrix originally supplied. The different mineral matrix may be used to cap the retained mineral matrix material. The mineral matrix provided for the cap may be less susceptible to becoming airborne than the original mineral matrix. The different mineral matrix and water mixture may be supplied through the dispensing conduit. The different mineral matrix and water mixture may be applied to the retained mineral matrix externally, for instance by spraying. A
different material may be applied to the retained mineral matrix once the dispensing of the mineral matrix has ceased and/or to cap the retained material. The different material may be a polymer. The different material may be provided on the outside of the retained mineral matrix and/or mingle therewith.
The retained mineral matrix may be capped with a water impermeable material.
The retained mineral matrix may be capped with a vapour permeable material.
The retained mineral matrix or capped retained material matrix may decrease in water content after having been dispensed for 24 hours and/or after capping. The decrease may be to water draining from the retained mineral matrix and/or water evaporating from the retained mineral matrix.
The retained mineral matrix may be kept in the dispensed form for more than 1 week, more than 1 month or even more then 4 months. The retained mineral matrix may remain at the location after the period for which it is stored in its dispensed or capped form. The retained mineral matrix may be reduced in height and/or moved to a configuration having a more level height across its extent, after the stored period. The retained mineral matrix may be moved to another location after the stored period.
The mineral matrix source and/or first location and/or mixing stage and/or flocculent source and/or dilution water conduit may be connectable to a plurality of dispensing conduits.
Preferably they are so connected to only one dispensing conduit at a time, with a mechanism for varying the dispensing conduit connected. Preferably the dispensing conduit connected is changed when a height of retained mineral matrix occurs for a given dispensing conduit.
An array comprising one or more mineral matrix sources and/or one or more flocculent sources and/or one or more dilution water sources and/or one or more further locations may be provided, together with a plurality of dispensing conduits.
The first aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
According to a second aspect of the invention we provide apparatus for obtaining at least a partial separation of a mineral matrix from water, the apparatus including:
a mineral matrix and water conduit connected to a first location;
a flocculent conduit connected directly or indirectly to the first location;
a mixing stage connected to the first location;
a dispensing conduit connected to the mixing stage;
a plurality of aperture provided in the dispensing conduit;
a drainage surface provided below the dispensing conduit;
a further location connected to the drainage surface.
The second aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
According to a third aspect of the invention we provide a kit of parts, the kit comprising one or more of:
a mineral matrix and water conduit connected to a first location;
a flocculent conduit connected directly or indirectly to the first location;
a mixing stage connected to the first location;
a dispensing conduit connected to the mixing stage;
a plurality of aperture provided in the dispensing conduit;
a drainage surface provided below the dispensing conduit;
a further location connected to the drainage surface;
The third aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
According to a fourth aspect of the invention, we provide a method of separating hydrocarbon from an hydrocarbon containing mineral matrix, the method including the provision of a mixture of the hydrocarbon containing mineral matrix and water, passing the mixture to a separation stage, the mixture being at at least 25 C in the separation stage, at least a part of the hydrocarbon passing to a first process stream and at least a part of the water and mineral matrix passing to a second process stream, the second process stream or one or more further process streams derived therefrom being processed to effect a separation of the mineral matrix from the water, the separation including a method of at least partially separating a mineral matrix from water, that method comprising:
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, the third mixture including a first part that is fed to the dispensing conduit and the third mixture including a second part that is fed to the dispensing conduit;
dispensing the third mixture at the dispensing stage, including dispensing the first part and the second part, the second part being dispensed on to at least a portion of the first part;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
The hydrocarbon may be present together with the hydrocarbon containing mineral matrix by virtue of the hydrocarbon being in the interstices and/or gaps and/or pores of the mineral matrix. The hydrocarbon containing mineral matrix, may be a sand and/or a clay incorporating matrices, such as bituminous sands, oil sands or tar sands.
Preferably the mixture is at at least 70 C in the separation stage.
Preferably the mixture is contacted with air in a primary separation stage.
The fourth aspect of the invention may include one or more of the features, possibilities or options set out elsewhere in this document.
Various embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:
Figure 1 is an illustration of apparatus according to the invention, before use commences;
Figure 2 is an illustration of the apparatus of Figure 1 after use has started;
Figure 3 is an illustration of the apparatus of Figure 1 and Figure 2, towards the end of use;
Figure 4 is a plan view of an array of apparatus according to the invention.
The methods and apparatus of the present invention are particularly suited to the processing of tailings from bituminous sand, oil sand or tar sand processing, but have application in other solid from liquid separations, particularly those having a high and/or variable clay content.
Tar sands, bituminous sands or oil sands are found in various locations throughout the world, and are increasingly being processed to extract their hydrocarbon content for subsequent processing and refining to give oil. At present, there is significant commercial exploitation of such oil sands in the Athabasca district of the Province of Alberta, Canada.
Such materials may contain between 5 and 20% hydrocarbon, between 1 and 10%
water and between 70 and 90% mineral matrix, substantially all inorganic solids. The mineral matrix is generally formed of a combination of clays, such as kaolinite, montmorillonite and illite, and frequently also include sands.
In the hot water process, hot water (with or without caustic soda) is added to the tar sand to form a slurry. A subsequent separation is provided, at elevated temperatures, frequently using aeration. The mineral matrix mainly reports to the tailings from this process.
However, a significant middling stream also exists which includes a mixture of hydrocarbon and finer parts of the mineral matrix.
The middling stream is generally processed further to extract further hydrocarbon from it and generates a further tailing stream consisting of fine clay, sand and other material.
This stream too is of considerable volume. A plant producing 150,000 barrels of oil a day can produce 200,000 gallons a minute of such a stream.
Other streams also exist, particularly from the solvent extraction processes and these too are difficult to address in terms of the tailings.
If successfully processed to remove a significant fraction of the water content, then the storage volume occupied and the pollution risk posed can be considerably reduced. The enormous amounts of tailings involve mean that any tailings treatment processing is a very cost sensitive step.
Figure 1 provides a schematic illustration of the apparatus used in an embodiment of the invention, in the configuration before processing of the tailings commences.
A drainage surface 1 is created on the edge of a tailings pond 3. The drainage surface 1 is inclined towards the tailings pond 3 to promote the flow of water reaching the drainage surface 1 towards and into the tailings pond 3. An angle of 2 or 3 degrees is sufficient for this purpose. By making the drainage surface 1 impermeable, or at least substantially impermeable, control over water passing through the drainage surface 1 and into the ground 5 below can be exercised.
An alternative drainage surface can be provided which is flat or even inclined away from the pond, with flow of water towards the pond occurring when the water level builds up on the drainage surface and overflows to the tailings pond.
The tailings pond 3 can be a new pond or an existing pond on whose edge the drainage surface 1 is provided. The function of the pond 3 is described in more detail later.
Leading from the tailings pond 3 is decant outlet pipe 7. This decant outlet pipe 7 is provided with a pump 8 and a first junction 9 where it joins a flocculent feed pipe 11. The flocculent feed pipe 11 is connected to a flocculent source 12.
The decant outlet pipe 7 is also provided with a second junction 13 where it joins a tailings inlet pipe 15. The tailings inlet pipe 15 is connected to a tailings source 16.
The tailings inlet pipe 15 connects to a static mixer 17 and then passes to the mixture pipe 18 which extends to the centre 19 of the drainage surface 3 in a generally horizontal configuration. A curved transition section 21 then changes the orientation to a generally vertical configuration for the tailings dispensing pipe 23. The mixing pipe 18 may have a length at least 125% of the height of the tailings dispensing pipe 23.
The tailings dispensing pipe 23 has a height of around 100 to 150m. The tailings dispensing pipe 23 is provided with a series of through apertures 25 provided at various positions along its height. Apertures may be provided at intervals of 15 to 40 cm.
In operation, the flocculent source 12 is provided with the flocculent or flocculent mixture intended for use. The flocculent source 12 can be supplied with flocculent prepared at a remote location and conveyed to the flocculent source 12 for loading there into, ready for use. The flocculent source 12 may include the flocculent preparation function, however. For instance, dried flocculent may be stored at the source 12 and be made up continuously or in batches to provide the flocculent for use.
An example of a flocculent useful in this process and apparatus is AF306HH.
AF306HH is an anionic polymer having a charge of 20mol% and an average molecular weight, AMW, of 18,000,000. The dosage of the flocculent may be 300 to 400g/tonne of tailings depending upon the clay content. The flocculent may be provided in the flocculent source 12 at a concentration of 1.5wt%.
A source of water is connected to the decant outlet pipe 7. This may be decant water 27 from the tailings pond 3 where that pond 3 is already in operation. If such decant water 27 is not initially available, then a water source 29 may be connected to the apparatus. Once the decant water 27 is available, it is the preferred water source for the decant outlet pipe 7.
When decant water 27 is used, the water will already contain some flocculent and so reuse that.
A tailings source 16 is connected to the tailings inlet pipe 15. This may be the overflow stream from a previous solid/liquid separation or thickening stage, for instance a hydrocyclone. A typical tailings source 16 may contain material of greater than 50% <44 microns.
The tailings dispensing pipe 23 and/or one or more of the other pipes may be provided with access locations in case of blockage. For instance, a sealable aperture may be provided in the base of the tailings dispensing pipe 23 to allow the column of mixture 34 therein to drain out on to the drainage surface 1. Back washing facilities may also be provided.
When processing starts, flocculent 30 is dispensed from the flocculent source 12, as a concentrated flocculent, into the water 27 in the decant outlet pipe 7 at first junction 9.
Limited mixing of the flocculent 30 and water 27 occurs at the first junction 9 and during the fluid flow to the second junction 13.
Tailings 32 from the tailings source 16 are passed along the tailings inlet pipe 16 to the second junction 13. Limited mixing of the tailings 32, decant water 27 and flocculent 30 occurs at the second junction 13 and during the flow to the static mixer 17.
The static mixer 17 can be provided in a variety of formats. The absence of rotating or other moving parts in the static mixer 17 means that there are no high shear locations within the mixer. A series of stationary guide plates 33 within the static mixer 17 give the systematic radial mixing of the materials flowing there through. A geometric flow pattern is preferred to avoid any random element to the mixing. Very through mixing in a very short distance is achieved. The mixing energy comes from a very small pressure drop across the static mixer 17. The effectiveness of the mixing is very useful in ensuring the minimum dose flocculent 30 needs to be used. There is no need to overdose so as to ensure all parts receive a minimum dose.
Once in the static mixer 17 the majority of the mixing of the tailings 32, decant water 27 and flocculent 30 occurs to provide the mixture 34. The provision of the static mixer 17 ensures thorough mixing, but in a low shear manner. The low shear conditions prevent the break up of the initial flocs as they form in the mixture 34. The addition of the decant water 27 recycles some of the flocculent and provides the appropriate % solids to the mixture 34 for good mixing, subsequent flocculation and whilst allowing flow through the apparatus. A
figure of approximately 15% solids is a good mark for the mixture 34 to attain.
Following the static mixer 17, the mixture 34 passes along the mixture pipe 18 for the necessary distance, 100m or so, to reach the centre 19 of the drainage surface 1. The mixture 34 then passes through the transition section 21 and up the tailings dispensing pipe 23. The flow passes up the tailings dispensing pipe 23 until the through apertures 25 are reached. The mixture 34 is able to flow out of the through apertures 25 into the space around the tailings dispensing pipe 23.
By the time of its passage through the apertures 25, the mixture 34 is heavily flocculated. Outside of the tailings dispensing pipe 23 this results in the water quickly decanting from the flocs. The flocs settle under gravity around the tailings dispensing pipe 23 and build up into a cone 60. The water 62 flows downhill and hence under the control of the drainage surface 1, into the tailings pond 3.
Within the tailings pond 3, further settling of ultra fine solids from the water may occur. This gives the decant water 27 in the upper layer of the tailings pond and that decant water can be reused via decant outlet pipe 7.
The solid/liquid mixture within the tailings pond 3 may be subjected to further treatment to promote further solid/liquid separation. Whilst part of the decant water 27 may be used in the above process, other water may be decanted from the tailings pond 3 for discharge to water courses and/or for reuse in the process plant, for instance in the "hot water" process.
Figure 2 illustrates the apparatus of Figure 1, part way through a processing cycle.
Continued flow of the mixture 34 into the tailings dispensing pipe 23 has resulted in the cone 60 building up around the tailings dispensing pipe 23. As lower apertures 25 are effectively blocked by the cone 60 building up, the majority of the flow of the mixture 34 out of the tailings dispensing pipe 23 occurs through higher and higher apertures 25. The cone 60 is formed of the flocs and is of a paste like consistency. The cone has an angle of repose, A, in excess of 40 . As the height of the cone 60 builds up, the mass of the cone 60 increasingly compresses the cone material and increases the dewatering.
Figure 3 illustrates the apparatus of Figure 1 and Figure 2, towards the end of a process cycle. The cone 60 has now nearly reached the full height of the tailings dispensing pipe 23, a height of 130m or more. A capping material 70 is now provided so as to coat the external surface of the cone 60. The capping material 70 is intended to prevent dry material on the surface of the cone 60 turning to dust and becoming airborne. A number of ways for providing the capping material 70 exist.
The capping material may be provided by flow of the capping material 70 up the tailings dispensing pipe 25 and down over the outside of the cone 60. This can be achieved by changing the material entering the apparatus from the tailings source 16.
For instance, coarser tailings of a size which won't become airborne could be introduced. In an similar manner, a different source location 80 could be connected instead of the tailings source 16, with that different source location 80 providing the coarser tailings.
A further alternative, not shown, would be to apply the capping material 70 from around the cone 60, rather than up through the tailings dispensing pipe 23.
For instance, the capping material 70 could be sprayed onto the cone 60. Polymer caps 70 may be used for this purpose.
Once capped with the capping material 70, the cone 60 can be left for a period of time.
Further dewatering may occur during this time. The cone 60 may simply be left in this state to provide storage of the dewatered material. Storage in this form, a cone of highly dewatered material takes up far less space than storage as a lower solids content material in relatively shallow tailings ponds or as slurries allowed to spread over large slopes and with a low depth only.
When one unit of apparatus of the above type has finished being loaded with the fine tailings material, the flow of the tailings 32, decant water 27 and flocculent 30 can be switched to a different, but equivalent unit of apparatus. These different units may be radially positioned around a common flocculent source 12, static mixer 17 etc, as shown in Figure 4, to provide an array. As shown, first unit Q and second unit R have been finished and have reached there full heights. Water from these continues to flow over drainage surface 1 which leads to channel C and hence to tailings pond 3. The third unit S has just started building up and so the cone 60 is small in diameter and height. The forth unit T has not started use. Flow to a unit is controlled by valve system V. A given process plant may have one or more such arrays available to it.
After dewatering has been completed to the desired degree, it is possible to remove the cone 60 of dewatered material and make use of it and/or store it at another location. This may result in the material being removed from around the tailings dispensing pipe 23 and the unit being reused for a fresh batch of material to dewater. The provision of the apparatus, however, is relatively cheap and so the apparatus can be discarded and/or demolished as part of the dismantling of the cone 60. The accessibility of the flocculent source 12 allows for the recovery of the apparatus there and the low cost of the PVC pipes used for the decant outlet pipe 7, tailings inlet pipe 15, mixture pipe18, transition section 21 and tailings dispensing pipe 23 allow them to be discarded.
The speed of dewatering and the extent of dewatering are higher than in the prior art.
This means that the site used is far more quickly made available for reuse or returning to the environment, than with tailings ponds or the like. The water in the tailings is also more quickly made available to the process plant once more. This reduces the overall water inventory required of the plant and may even allow heat in the water to effectively be recovered to the plant by the prompt return of the water, rather than the loss of that heat to the environment because the water sits for long periods during the dewatering.
The apparatus and method results in a cone of dewatered tailings at a higher density than is achieved using prior art approaches, such as tailings pond settling, mechanical thickeners etc. The cost of the processing is also lower than with prior art approaches, in terms of hardware costs and reagent costs when compared with centrifuges, and in terms of reagent costs when compared with tailings ponds.
Claims (22)
1. A method of at least partially separating a mineral matrix from water, the method comprising:
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, wherein the dispending conduit is a vertical conduit; and dispensing the third mixture at the dispensing stage;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, wherein the dispending conduit is a vertical conduit; and dispensing the third mixture at the dispensing stage;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
2. A method according to claim 1 in which the mixing stage is provided by a static mixer.
3. A method according to claim 1 or claim 2 in which the mixing stage provides a shear rate of less than 100s -1.
4. A method according to claim 1 or claim 2 in which the mixing stage provides a shear rate of less than 15s -1.
5. A method according to any one of claims 1 to 4 in which the method provides a separation in which a % solids of 72% is reached in a time frame of 3 minutes after the mixture is dispensed and/or a separation in which a % solids of 94%, is reached in a time frame of 2 weeks after the mixture is dispensed.
6. A method according to any one of claims 1 to 5 in which the first location is a junction of a conduit carrying the mineral matrix and water mixture and a conduit carrying another stream, the another stream including the flocculent.
7. A method according to any one of claims 1 to 6 in which the flocculent has an average molecular weight of at least 5,000,000 and an anionic charge of between 1 and 50%.
8. A method according to any one of claims 1 to 7 in which the dosage of the flocculent used is between 250 to 450g/tonne of mineral matrix in the mixture.
9. A method according to any one of claims 1 to 8 in which dilution water is added to the mixture to give the second mixture and the dilution water is added from outside the process circuit of the method and/or the dilution water is water extracted from the further location as decant water therefrom.
10. A method according to any one of claims 1 to 9 in which the second and/or third mixture has a solids content of less than 20%.
11. A method according to any one of claims 1 to 10 in which the dispensing conduit has a height of more than 25m.
12. A method according to any one of claims I to 11 in which a plurality of through apertures are provided along the length of the dispensing conduit.
13. A method according to any one of claims 1 to 12 in which the time period between the first part of the third mixture leaving the mixing stage and being dispensed from the dispensing conduit is less than 15 seconds.
14. A method according to any one of claims 1 to 13 in which the third mixture is dispensed so that the third mixture flows over the outside surface of the already retained mineral matrix.
15. A method according to any one of claims 1 to 14 in which water is withdrawn from the further location and is used in a mineral extraction process.
16. A method according to claim 15 in which the water is withdrawn from the further location and is used in the extraction of hydrocarbon from a mineral matrix.
17. A method according to any one of claims 1 to 16 in which the supply of mineral matrix and water mixture to the process is stopped after the retained mineral matrix reaches a given height compared with the height of the dispensing conduit and/or relative to its own base.
18. A method according to any of claims 1 to 16 in which the supply of mineral matrix and water mixture is diverted to another dispensing stage after the retained mineral matrix reaches a given height compared with the height of the dispensing conduit and/or relative to its own base.
19. A method according to any one of claims 1 to 18 in which after the end of the supply of mineral matrix and water mixture to a dispensing location, a different mineral matrix and water mixture is provided to that dispensing location.
20. A method according to any one of claims 1 to 18 in which a different material is used to cap the retained mineral matrix material and wherein the different material is a different mineral matrix and/or a polymer.
21. Apparatus for obtaining at least a partial separation of a mineral matrix from water, the apparatus comprising:
a mineral matrix and water conduit connected to a first location;
a flocculent conduit connected directly or indirectly to the first location;
a mixing stage connected to the first location;
a dispensing conduit connected to the mixing stage;
a plurality of aperture provided in the dispensing conduit;
a drainage surface provided below the dispensing conduit; and a further location connected to the drainage surface.
a mineral matrix and water conduit connected to a first location;
a flocculent conduit connected directly or indirectly to the first location;
a mixing stage connected to the first location;
a dispensing conduit connected to the mixing stage;
a plurality of aperture provided in the dispensing conduit;
a drainage surface provided below the dispensing conduit; and a further location connected to the drainage surface.
22. A method of separating hydrocarbon from an hydrocarbon containing mineral matrix, the method including the provision of a mixture of the hydrocarbon containing mineral matrix and water, passing the mixture to a separation stage, the mixture being at least 25°C in the separation stage, at least a part of the hydrocarbon passing to a first process stream and at least a part of the water and mineral matrix passing to a second process stream, the second process stream or one or more further process streams derived therefrom being processed to effect a separation of the mineral matrix from the water, the separation including a method of at least partially separating a mineral matrix from water, that method comprising:
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, the third mixture including a first part that is fed to the dispensing conduit and the third mixture including a second part that is fed to the dispensing conduit;
dispensing the third mixture at the dispensing stage, including dispensing the first part and the second part, the second part being dispensed on to at least a portion of the first part;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
providing a mineral matrix source, the mineral matrix source having a mineral matrix and water mixture;
feeding the mineral matrix and water mixture past a first location;
introducing a flocculent to the mineral matrix and water mixture at the first location to give a second mixture;
passing the second mixture through a mixing stage to give a third mixture;
feeding the third mixture to a dispensing conduit provided at a dispensing stage, the third mixture including a first part that is fed to the dispensing conduit and the third mixture including a second part that is fed to the dispensing conduit;
dispensing the third mixture at the dispensing stage, including dispensing the first part and the second part, the second part being dispensed on to at least a portion of the first part;
wherein at least a part of the mineral matrix is retained at the dispensing stage and at least a part of the water flows away from the dispensing stage to a further location.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2649928A CA2649928C (en) | 2009-01-15 | 2009-01-15 | Improvements in and relating to separating solids and liquids |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2649928A CA2649928C (en) | 2009-01-15 | 2009-01-15 | Improvements in and relating to separating solids and liquids |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2649928A1 CA2649928A1 (en) | 2010-07-15 |
| CA2649928C true CA2649928C (en) | 2016-07-12 |
Family
ID=42352622
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2649928A Active CA2649928C (en) | 2009-01-15 | 2009-01-15 | Improvements in and relating to separating solids and liquids |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2649928C (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2729457C (en) | 2011-01-27 | 2013-08-06 | Fort Hills Energy L.P. | Process for integration of paraffinic froth treatment hub and a bitumen ore mining and extraction facility |
| CA2906715C (en) | 2011-02-25 | 2016-07-26 | Fort Hills Energy L.P. | Process for treating high paraffin diluted bitumen |
| CA2931815C (en) | 2011-03-01 | 2020-10-27 | Fort Hills Energy L.P. | Process and unit for solvent recovery from solvent diluted tailings derived from bitumen froth treatment |
| CA2806891C (en) | 2011-03-04 | 2014-12-09 | Fort Hills Energy L.P. | A solvent treatment process for treating bitumen froth with axi-symmetric distribution of separator feed |
| CA2735311C (en) | 2011-03-22 | 2013-09-24 | Fort Hills Energy L.P. | Process for direct steam injection heating of oil sands bitumen froth |
| CA2815785C (en) | 2011-04-15 | 2014-10-21 | Fort Hills Energy L.P. | Heat recovery for bitumen froth treatment plant integration with temperature circulation loop circuits |
| CA3077966C (en) | 2011-04-28 | 2022-11-22 | Fort Hills Energy L.P. | Recovery of solvent from diluted tailings by feeding a solvent diluted tailings to a digester device |
| CA2832269C (en) | 2011-05-18 | 2017-10-17 | Fort Hills Energy L.P. | Temperature control of bitumen froth treatment process with trim heating of solvent streams |
| CA2823459C (en) | 2013-08-09 | 2015-06-23 | Imperial Oil Resources Limited | Method of using a silicate-containing stream from a hydrocarbon operation or from a geothermal source to treat fluid tailings by chemically-induced micro-agglomeration |
-
2009
- 2009-01-15 CA CA2649928A patent/CA2649928C/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CA2649928A1 (en) | 2010-07-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2649928C (en) | Improvements in and relating to separating solids and liquids | |
| CA2750995C (en) | Paraffinic froth treatment with conditioning to enhance paraffin liberation from flocks | |
| EP2477707B1 (en) | Process for drying fine tailings | |
| CA2772053C (en) | Pre-treatment of fine tailings by coarse debris removal | |
| CN102695551A (en) | Depositing and farming methods for drying oil sand mature fine tailings | |
| CN101905099B (en) | Tailing treatment method and system | |
| US20250041775A1 (en) | Water recovery systems and methods | |
| KR20210023274A (en) | Integrated waste water treatment tank facility for wet type sand product plant | |
| CN202529898U (en) | Integrated condensation and separation reactor of waste water pipe bundle with oil sludge | |
| CA2867834C (en) | Tailings solvent recovery unit feed control | |
| JPS5927239B2 (en) | Mud water treatment equipment | |
| CN105293763A (en) | Basic sewage treatment process of mining selecting industry | |
| CA2773143A1 (en) | A system and method for bitumen recovery and tailings consolidation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |
Effective date: 20140110 |