CA1076363A - Method for the removal of mercury from sludges containing same - Google Patents
Method for the removal of mercury from sludges containing sameInfo
- Publication number
- CA1076363A CA1076363A CA251,654A CA251654A CA1076363A CA 1076363 A CA1076363 A CA 1076363A CA 251654 A CA251654 A CA 251654A CA 1076363 A CA1076363 A CA 1076363A
- Authority
- CA
- Canada
- Prior art keywords
- mercury
- water
- mass
- sludge
- temperature
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B43/00—Obtaining mercury
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G13/00—Compounds of mercury
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/046—Treatment of water, waste water, or sewage by heating by distillation or evaporation under vacuum produced by a barometric column
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/048—Purification of waste water by evaporation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/004—Sludge detoxification
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/02—Temperature
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/06—Pressure conditions
- C02F2301/063—Underpressure, vacuum
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Treatment Of Sludge (AREA)
- Processing Of Solid Wastes (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Treatment Of Liquids With Adsorbents In General (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
Elemental mercury is recovered from a mercury-occluding sludge containing no more than 50% moisture by heating the sludge to a temperature of from 200 to 350°C under a negative pressure of from 0.06 to 0.1 effective atmospheres to convert the sludge into a powdered ashy mass, discharging the ashes into a mass of water circulated in a closed loop, superheating the water vapor evolved from the water mass so as to keep all the mercury values in the vapor phase, condensing the water and mercury vapors and gravimetrically separating the water and the mercury condensates from one another. The invention enables one to achieve a high efficiency of recovery.
Elemental mercury is recovered from a mercury-occluding sludge containing no more than 50% moisture by heating the sludge to a temperature of from 200 to 350°C under a negative pressure of from 0.06 to 0.1 effective atmospheres to convert the sludge into a powdered ashy mass, discharging the ashes into a mass of water circulated in a closed loop, superheating the water vapor evolved from the water mass so as to keep all the mercury values in the vapor phase, condensing the water and mercury vapors and gravimetrically separating the water and the mercury condensates from one another. The invention enables one to achieve a high efficiency of recovery.
Description
CASfi 852 This invention relates to a method ~or th~ purification of mercury-containin~ sludges~ consisting in subjecting the sludges to heating in a vacuo.
Many chemical and electrochemical processes~ in which mercury or merc~ry compounds are used, involve pollution problems since the effluents from these processes ~ waters and exhaust ~ases) contain mercury in such an amount as not to allow dis-charge without serious hazards A number of different methods have been suggested for removin~ metallic mercury from the discharged sludges~ such as those coming from the cells ~or the electrolysis~ from processes which use mercury compounds as the catalysts and so on.
The sludges can, for example~ be filtered in rotary fil-ters under a negative pressure (for the preliminary remo~al of water ) to undergo subsequently heating and dryin~ in multiple ovens~
collecting mercury which is evaporated (distilled~ in condenser systems (Chemical Engineering Progress7 March 197~ pages 73-80 )~
or it is possible to resort to a treatment with resins which act as chelating compounds and can be regenerated thus permitting tha~
the separated mercury is recoverede(Chemical ~conomy and ~nginee-ring Review3 5 1972 page~ 64~65 ~.
No one of the above mentioned procPsses9 however~ succeeds in removing mercury up to satisfactory levels (it has not been e~er possible to go, in an appreciable manner~ below 0,1 p~p.
~5 million) We have now surprisingly ascsrtained that it is possible further to lower the mercury level or substantially attain the complete removal thereof It is thus an object of the present invention to provide a simple and cheap method for the remo~al mercury ~rom sludges
Many chemical and electrochemical processes~ in which mercury or merc~ry compounds are used, involve pollution problems since the effluents from these processes ~ waters and exhaust ~ases) contain mercury in such an amount as not to allow dis-charge without serious hazards A number of different methods have been suggested for removin~ metallic mercury from the discharged sludges~ such as those coming from the cells ~or the electrolysis~ from processes which use mercury compounds as the catalysts and so on.
The sludges can, for example~ be filtered in rotary fil-ters under a negative pressure (for the preliminary remo~al of water ) to undergo subsequently heating and dryin~ in multiple ovens~
collecting mercury which is evaporated (distilled~ in condenser systems (Chemical Engineering Progress7 March 197~ pages 73-80 )~
or it is possible to resort to a treatment with resins which act as chelating compounds and can be regenerated thus permitting tha~
the separated mercury is recoverede(Chemical ~conomy and ~nginee-ring Review3 5 1972 page~ 64~65 ~.
No one of the above mentioned procPsses9 however~ succeeds in removing mercury up to satisfactory levels (it has not been e~er possible to go, in an appreciable manner~ below 0,1 p~p.
~5 million) We have now surprisingly ascsrtained that it is possible further to lower the mercury level or substantially attain the complete removal thereof It is thus an object of the present invention to provide a simple and cheap method for the remo~al mercury ~rom sludges
2.
~(i7636~i containing it, consistlng in hea-tlng the sludges themselves in a vacuo so ~s ~o vaporize mercury which~ ~hen, under similar conditions, is condensed anew and collected.
The residual sludges and condensates can thus be dischargèd without experiencin~ no more hazards of pollution, inasmuch as the removal of mercury can be pushed so Ear as to obtain, in such residues, values in the order of 10 8%.
More particularly, the method of the inven-tion comprises heating a mercury-occluding sludge containing no more than 50% moisture, to a temperature of from 200 to 350C under a negative pressure of from 0.06 to 0.1 effective atmospheres to convert the sludge into a powdered ashy mass, discharging -the ashes into a mass of water circulated in a closed loop, super-heating the water vapor evolved from the water mass so as -to keep all the mercury values in the vapor phase, condensing the water and mercury vapors and gravimetrically separating the water and the mercury condensates from one another.
Preferably, the condensation of the water and~mercury vapors is effected at a temperature between 2nc and 50C and ~0 under a negative pressure of from 0. n6 to 0.1 effective atmospheres.
Traces of mercury vapor may be removed by a further c~ndensation effected under a pressure ranging from 2 to 3 effective atmospheres and at a temperature comprised be-tween 5C
and 35C, prior to discharging the inert gases into the a-tmosphere.
In order that the method of the invention may be better understood reference will be made, in the progress of the specification, to a particular continuous system which is adapted to carry -the method into practice.
It is obvious, however, that -this is a mere illus-trative example and that anyone skilled in the art is capable of putting the method into practice by using other machinery and wi-thou-t thereby departing from the scope of this invention.
`` 1~763f~;~
With reference to the diagram as shown in the drawing, the method can be regarded as being carried out in two stages, which correspond to two discrete sections, that is, an oven for the continuous roasting of the sludges and a eondensation system under subatmospherical pressures of the barometric type.
The oven described herein is of the continuous type, which 3a-~7~3~;3 is indirectly heated by means of electric resistors. It is eom-posed by a horizontal cylindrical body 1, which is heated from the outside by a set of resistors 2, independent from each other;
so as to have several heat degrees, according to the load of the oven and the concentration of water and mercury.
At one end of the cvvlindrical body~ there is formed the horizontal sludge inlet mouth 3, on the other~ there have been formed a "dome" 4, for drawing vapors and, in the underlying por-tion~ a mouth 5, the diameter of which is equal to that of the oven, for dumping the exhausted ashes. The sludge loading mecha-nism as shown in the cross-sectional view A-A is of the pres~ing screw 6 type (the pitch of the screw grows shorter and shorter) with an extrusion head equipped with cu~ting blades; the system is driven by an electric motor with reduction gear having a speed variator 7 Such an exp,edient is responsible, during processing, of the perfectly tight seal against the losses of vacuum in the system.
The automatic variation of the rpm of the loading screw is a function of the temperature of the vapors (t) in the terminal section of the oven conoerned. The product charged into the oven must be a sludge having at the most 45% - 50% moisture and which has been neu-tralized (if and when acidic) at a pH which is certain-ly alkaline (8 to 9) In the interior of the cylindrical body a shaft 8 is rotated~ which equipped with a screw 9 for the feeding of material, which is equipped with special scraping blades 10~
the latter providing to stir the sludges as th0y are being roasted while ensurin~ moreover, that no danger of jamming is possible for the screw.
The rotation of the screw is furnished by a speed reducing gear 11, arranged at either end of the cylindrical body of the oven, the electric motor of which, 12, (two-speed) is of the kind which transfers the torque by magnetic expanders so as to guarantee 1~7~3~3 the vacuum tightness in an absolute manner.
The reducing unit ll, of necessity, will be arranged in a vacuum chamber 13 and separated Erom the oven body by a gland seal. The run of the oven is very simple and wholly automated.
S The sludges~ as they come from the loadirg extruder, are ~ed forward by the screw so that~ after having been first dehydra-ted~ start to become roasted, the result being the distillation of the mercury contents.
The working conditions are o.Q6 effective atmospheres at about 250C, these conditions being such as to ensure the vapo rization of all the mercury as contained in the sludges concerned.
These conditions as specified above are automatically maintained by the feeding rate of flow o the slu~ges and by the following run parameters :
a) speed of rotation of the feeding screw (2 speeds ), b) insertion of the several sets of electric resistors, There is thus the possibility of ensuring that the mercury contents in the ashes emerging from khe screw is virtually æeroi Inasmuch as in the terminal portion of the oven it is i~pe-~0 rative to ensure that all the vapors evolved from the sludges are conveyed towards the condensation system while it is con-currently required that the exhausted ashes be continually re-moved from a system which is under a negative pressure, the follow-ing expedient has been envisaged :
The ashes emerging from the screw fall into a duct 14~ which is also heated by electric resistors~ which feeds them to a con-tainer 15, the latter being placed at a barometric level~ a so-called "dissolver" in which a certain level of water 16 is presentO
The temperature of such water is maintained, by an automa~
tic system~ constantly at a value (about 37C) which ls slightly above th~ temperature correspondin~ to the vapor pr~sure of water under the same conditions of normal run of o.o6 effective ~7~3~3 atmosphares (t = 35.8C). This exp~dient a~-t~ in such a way that~ when the hot ashes fall in water~ a certain amount o~
steam (a direct function of the ash temperature and their speci-fic heat) which, superheated by the hot walls of the duct to ~50C~
acts in counterflow relative to the ashes and prevents a condensa-tion of mercury and thus the presence of the metal in the exhausted ashes.
In order~ then~ to encourage the dissolution of the ashes in water~ there is a pump 17 which provides a vigorous recircula-tion through the dissolver.
Lastly, with conventional level-checking systems~ thermo-statically controlled water is provided and fed in, as the dis-solved ashes are being withdrawn. The vapors emerging from the dome 4 of the oven at the temperature of 250C contain, almost entirely, superheated steam coming, predominantly, from the moisture contained in the fed in sludges plus the counterflow washing steam of the exhausted ashes plus~ obviously~ mercury vapors~
All these steam and vapors are conveyed to a vertical tube bundle condenser 18~ which is water-cooled (processing in the tubes on account of the possibility of dusts being entrained) The condensate is collected in the bottom section of an accumulator 19~ having a hydraulic seal~ which is placed at a barometric level and the outlet of which directl.y communicate~
at the zero level~ with an atmospherical collectlng vessel 20.
~5 Such a condensate is composed by water and msrcury: water overflows through an overflow outlet 21~ whereas the mercury is automatically dumped by a sipho~ 22 from the bottom of the vessel The vapor phase of the accu~lulat.or 19 is composed by steam plus traces of mercury vapors plus the unavoidable noncondensed fractions; these latter ar-e composed almost exclusively by air~
coming from the air dissolved in ash dissolving water and that occluded in the neutrali~ed loaded sludges.
~763~i3 These vapors are drawn by a liquid ring vacuum pump 23 which is i~t~ ed to keep the system at a pressure of 0~06 effective atmospheres.
Obviously, the percentage of mercury vapors at the in-take side of the p~mp is a direct function of the temperature of the cooling water in the exchanger 18 3 and thus to ensure the value of 0.1 milligrams per normal cubis meter of Hg in the at -spherical effluent~ the delivery of the pump is sent to a second water-condenser 24~ wherein at the pressure of 1 to 3 atmo-spheres~ as controlled by a pressure adjuster~ an addi~ional condensation is effected~
As an alternative~ if the specifications o~ the vacuum pump do not permit a very high pressure drop~ the coolant for the condenser 24 can also be water cooled at least as low as 1$ 4C - 60C, coming from a refrigeration system which will have very reduced dimensions on account of the small amounts of vapor involved.
Summing up~ irrespective of whichever of the two above mentioned systems is adopted~ the quantity of the atmospherical effluent is at any rate in the order of a few tens of liters an hour with a contents of Hg which is always less than 0,1 milli-grams per normal cubic meter~
7.
~(i7636~i containing it, consistlng in hea-tlng the sludges themselves in a vacuo so ~s ~o vaporize mercury which~ ~hen, under similar conditions, is condensed anew and collected.
The residual sludges and condensates can thus be dischargèd without experiencin~ no more hazards of pollution, inasmuch as the removal of mercury can be pushed so Ear as to obtain, in such residues, values in the order of 10 8%.
More particularly, the method of the inven-tion comprises heating a mercury-occluding sludge containing no more than 50% moisture, to a temperature of from 200 to 350C under a negative pressure of from 0.06 to 0.1 effective atmospheres to convert the sludge into a powdered ashy mass, discharging -the ashes into a mass of water circulated in a closed loop, super-heating the water vapor evolved from the water mass so as -to keep all the mercury values in the vapor phase, condensing the water and mercury vapors and gravimetrically separating the water and the mercury condensates from one another.
Preferably, the condensation of the water and~mercury vapors is effected at a temperature between 2nc and 50C and ~0 under a negative pressure of from 0. n6 to 0.1 effective atmospheres.
Traces of mercury vapor may be removed by a further c~ndensation effected under a pressure ranging from 2 to 3 effective atmospheres and at a temperature comprised be-tween 5C
and 35C, prior to discharging the inert gases into the a-tmosphere.
In order that the method of the invention may be better understood reference will be made, in the progress of the specification, to a particular continuous system which is adapted to carry -the method into practice.
It is obvious, however, that -this is a mere illus-trative example and that anyone skilled in the art is capable of putting the method into practice by using other machinery and wi-thou-t thereby departing from the scope of this invention.
`` 1~763f~;~
With reference to the diagram as shown in the drawing, the method can be regarded as being carried out in two stages, which correspond to two discrete sections, that is, an oven for the continuous roasting of the sludges and a eondensation system under subatmospherical pressures of the barometric type.
The oven described herein is of the continuous type, which 3a-~7~3~;3 is indirectly heated by means of electric resistors. It is eom-posed by a horizontal cylindrical body 1, which is heated from the outside by a set of resistors 2, independent from each other;
so as to have several heat degrees, according to the load of the oven and the concentration of water and mercury.
At one end of the cvvlindrical body~ there is formed the horizontal sludge inlet mouth 3, on the other~ there have been formed a "dome" 4, for drawing vapors and, in the underlying por-tion~ a mouth 5, the diameter of which is equal to that of the oven, for dumping the exhausted ashes. The sludge loading mecha-nism as shown in the cross-sectional view A-A is of the pres~ing screw 6 type (the pitch of the screw grows shorter and shorter) with an extrusion head equipped with cu~ting blades; the system is driven by an electric motor with reduction gear having a speed variator 7 Such an exp,edient is responsible, during processing, of the perfectly tight seal against the losses of vacuum in the system.
The automatic variation of the rpm of the loading screw is a function of the temperature of the vapors (t) in the terminal section of the oven conoerned. The product charged into the oven must be a sludge having at the most 45% - 50% moisture and which has been neu-tralized (if and when acidic) at a pH which is certain-ly alkaline (8 to 9) In the interior of the cylindrical body a shaft 8 is rotated~ which equipped with a screw 9 for the feeding of material, which is equipped with special scraping blades 10~
the latter providing to stir the sludges as th0y are being roasted while ensurin~ moreover, that no danger of jamming is possible for the screw.
The rotation of the screw is furnished by a speed reducing gear 11, arranged at either end of the cylindrical body of the oven, the electric motor of which, 12, (two-speed) is of the kind which transfers the torque by magnetic expanders so as to guarantee 1~7~3~3 the vacuum tightness in an absolute manner.
The reducing unit ll, of necessity, will be arranged in a vacuum chamber 13 and separated Erom the oven body by a gland seal. The run of the oven is very simple and wholly automated.
S The sludges~ as they come from the loadirg extruder, are ~ed forward by the screw so that~ after having been first dehydra-ted~ start to become roasted, the result being the distillation of the mercury contents.
The working conditions are o.Q6 effective atmospheres at about 250C, these conditions being such as to ensure the vapo rization of all the mercury as contained in the sludges concerned.
These conditions as specified above are automatically maintained by the feeding rate of flow o the slu~ges and by the following run parameters :
a) speed of rotation of the feeding screw (2 speeds ), b) insertion of the several sets of electric resistors, There is thus the possibility of ensuring that the mercury contents in the ashes emerging from khe screw is virtually æeroi Inasmuch as in the terminal portion of the oven it is i~pe-~0 rative to ensure that all the vapors evolved from the sludges are conveyed towards the condensation system while it is con-currently required that the exhausted ashes be continually re-moved from a system which is under a negative pressure, the follow-ing expedient has been envisaged :
The ashes emerging from the screw fall into a duct 14~ which is also heated by electric resistors~ which feeds them to a con-tainer 15, the latter being placed at a barometric level~ a so-called "dissolver" in which a certain level of water 16 is presentO
The temperature of such water is maintained, by an automa~
tic system~ constantly at a value (about 37C) which ls slightly above th~ temperature correspondin~ to the vapor pr~sure of water under the same conditions of normal run of o.o6 effective ~7~3~3 atmosphares (t = 35.8C). This exp~dient a~-t~ in such a way that~ when the hot ashes fall in water~ a certain amount o~
steam (a direct function of the ash temperature and their speci-fic heat) which, superheated by the hot walls of the duct to ~50C~
acts in counterflow relative to the ashes and prevents a condensa-tion of mercury and thus the presence of the metal in the exhausted ashes.
In order~ then~ to encourage the dissolution of the ashes in water~ there is a pump 17 which provides a vigorous recircula-tion through the dissolver.
Lastly, with conventional level-checking systems~ thermo-statically controlled water is provided and fed in, as the dis-solved ashes are being withdrawn. The vapors emerging from the dome 4 of the oven at the temperature of 250C contain, almost entirely, superheated steam coming, predominantly, from the moisture contained in the fed in sludges plus the counterflow washing steam of the exhausted ashes plus~ obviously~ mercury vapors~
All these steam and vapors are conveyed to a vertical tube bundle condenser 18~ which is water-cooled (processing in the tubes on account of the possibility of dusts being entrained) The condensate is collected in the bottom section of an accumulator 19~ having a hydraulic seal~ which is placed at a barometric level and the outlet of which directl.y communicate~
at the zero level~ with an atmospherical collectlng vessel 20.
~5 Such a condensate is composed by water and msrcury: water overflows through an overflow outlet 21~ whereas the mercury is automatically dumped by a sipho~ 22 from the bottom of the vessel The vapor phase of the accu~lulat.or 19 is composed by steam plus traces of mercury vapors plus the unavoidable noncondensed fractions; these latter ar-e composed almost exclusively by air~
coming from the air dissolved in ash dissolving water and that occluded in the neutrali~ed loaded sludges.
~763~i3 These vapors are drawn by a liquid ring vacuum pump 23 which is i~t~ ed to keep the system at a pressure of 0~06 effective atmospheres.
Obviously, the percentage of mercury vapors at the in-take side of the p~mp is a direct function of the temperature of the cooling water in the exchanger 18 3 and thus to ensure the value of 0.1 milligrams per normal cubis meter of Hg in the at -spherical effluent~ the delivery of the pump is sent to a second water-condenser 24~ wherein at the pressure of 1 to 3 atmo-spheres~ as controlled by a pressure adjuster~ an addi~ional condensation is effected~
As an alternative~ if the specifications o~ the vacuum pump do not permit a very high pressure drop~ the coolant for the condenser 24 can also be water cooled at least as low as 1$ 4C - 60C, coming from a refrigeration system which will have very reduced dimensions on account of the small amounts of vapor involved.
Summing up~ irrespective of whichever of the two above mentioned systems is adopted~ the quantity of the atmospherical effluent is at any rate in the order of a few tens of liters an hour with a contents of Hg which is always less than 0,1 milli-grams per normal cubic meter~
7.
Claims (3)
1. A method for recovering elemental mercury from a mercury-occluding sludge containing no more than 50% moisture, which comprises heating said sludge to a temperature of from 200 to 350°C under a negative pressure of from 0.06 to 0.1 a effective atmospheres to convert said sludge into a powdered ashy mass, discharging said ashes into a mass of water circulated in a closed loop, superheating the water vapor evolved from said water mass so as to keep all the mercury values in the vapor phase, condensing said water and mercury vapors and gravimetrically separating the water and the mercury condensates from one another.
2. A method according to claim 1, wherein the condensation of the water and mercury vapors is effected at a temperature between 20°C and 50°C and under a negative pressure of from 0.06 to 0.1 effective atmospheres.
3. A method according to claim 1, wherein traces of mercury vapor are removed by a further condensation effected under a pressure ranging from 2 to 3 effective atmospheres and at a temperature comprised between 5°C and 35°C.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT2299775A IT1037842B (en) | 1975-05-05 | 1975-05-05 | PROCESS FOR THE REMOVAL OF MERCURY FROM SLUDGE CONTAINING IT |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1076363A true CA1076363A (en) | 1980-04-29 |
Family
ID=11202687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA251,654A Expired CA1076363A (en) | 1975-05-05 | 1976-05-03 | Method for the removal of mercury from sludges containing same |
Country Status (14)
| Country | Link |
|---|---|
| JP (1) | JPS5915718B2 (en) |
| AU (1) | AU499936B2 (en) |
| BE (1) | BE841467A (en) |
| CA (1) | CA1076363A (en) |
| DD (1) | DD125000A5 (en) |
| DE (1) | DE2619883A1 (en) |
| DK (1) | DK144125C (en) |
| FR (1) | FR2310317A1 (en) |
| GB (1) | GB1524464A (en) |
| IT (1) | IT1037842B (en) |
| NL (1) | NL7604821A (en) |
| NO (1) | NO142871C (en) |
| SE (1) | SE408560B (en) |
| ZA (1) | ZA762295B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102189092A (en) * | 2010-03-01 | 2011-09-21 | 王自新 | Method for realizing comprehensive recycling of mercury-containing waste |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE410868B (en) * | 1978-04-12 | 1979-11-12 | Lumalampan Ab | SET AND DEVICE FOR SEPARATING MERCURY FROM SOLID MATERIAL BY DISTILLATION UNDER VACUUM |
| AT377124B (en) * | 1983-02-01 | 1985-02-11 | Voest Alpine Ag | DEVICE FOR THERMALLY UNLOCKING USED GALVANIC ELEMENTS |
| US5382328A (en) * | 1988-04-27 | 1995-01-17 | Drespa; Gerd | Installation for processing waste oil |
| DE3816282C1 (en) * | 1988-05-12 | 1989-10-05 | Gerhard Dipl.-Ing. 6940 Weinheim De Bernecker | |
| DE4122113A1 (en) * | 1990-10-22 | 1992-04-23 | Dinda Kickdown Gmbh | Removing mercury from sewage sludge - by drying in two stages and use of dried sludge as fuel, esp. with fossil fuel in rotating cement furnace |
| DE4127506C1 (en) * | 1991-08-20 | 1992-10-15 | Hak-Anlagenbau Gmbh, 2000 Hamburg, De | |
| DE19547151C2 (en) * | 1995-12-16 | 1999-06-17 | Ald Vacuum Techn Gmbh | Method and device for working up mixtures of substances with at least two phases with different boiling temperatures |
| DE19727565A1 (en) * | 1997-06-28 | 1999-01-07 | Ald Vacuum Techn Gmbh | Process and device for working up mixtures of substances containing heavy metals or halogenated hydrocarbons |
| JP3514244B2 (en) * | 2001-03-30 | 2004-03-31 | 松下電器産業株式会社 | Mercury separation and recovery method and mercury separation and recovery device |
| JP5580650B2 (en) * | 2010-04-12 | 2014-08-27 | 株式会社御池鐵工所 | Marine waste recycling plant |
| JP2014117675A (en) * | 2012-12-18 | 2014-06-30 | Sumitomo Osaka Cement Co Ltd | Method and apparatus for treating exhaust gas |
| CN112373095B (en) * | 2020-10-26 | 2022-09-30 | 永康市凡谷进出口有限公司 | Kitchen waste sewage treatment device and treatment method thereof |
-
1975
- 1975-05-05 IT IT2299775A patent/IT1037842B/en active
-
1976
- 1976-04-15 ZA ZA762295A patent/ZA762295B/en unknown
- 1976-04-20 AU AU13121/76A patent/AU499936B2/en not_active Expired
- 1976-05-03 GB GB1803576A patent/GB1524464A/en not_active Expired
- 1976-05-03 CA CA251,654A patent/CA1076363A/en not_active Expired
- 1976-05-03 FR FR7613169A patent/FR2310317A1/en active Granted
- 1976-05-03 DK DK197176A patent/DK144125C/en not_active IP Right Cessation
- 1976-05-03 SE SE7605055A patent/SE408560B/en unknown
- 1976-05-04 DD DD19266776A patent/DD125000A5/xx unknown
- 1976-05-04 JP JP51050037A patent/JPS5915718B2/en not_active Expired
- 1976-05-04 NO NO761536A patent/NO142871C/en unknown
- 1976-05-05 BE BE166737A patent/BE841467A/en not_active IP Right Cessation
- 1976-05-05 DE DE19762619883 patent/DE2619883A1/en not_active Ceased
- 1976-05-05 NL NL7604821A patent/NL7604821A/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102189092A (en) * | 2010-03-01 | 2011-09-21 | 王自新 | Method for realizing comprehensive recycling of mercury-containing waste |
Also Published As
| Publication number | Publication date |
|---|---|
| NO142871B (en) | 1980-07-28 |
| ZA762295B (en) | 1977-04-27 |
| BE841467A (en) | 1976-11-05 |
| DK144125C (en) | 1982-06-01 |
| FR2310317A1 (en) | 1976-12-03 |
| JPS51134377A (en) | 1976-11-20 |
| DK197176A (en) | 1976-11-06 |
| JPS5915718B2 (en) | 1984-04-11 |
| NL7604821A (en) | 1976-11-09 |
| DK144125B (en) | 1981-12-14 |
| AU1312176A (en) | 1977-10-27 |
| GB1524464A (en) | 1978-09-13 |
| FR2310317B1 (en) | 1980-07-25 |
| SE7605055L (en) | 1976-11-06 |
| SE408560B (en) | 1979-06-18 |
| DE2619883A1 (en) | 1976-11-18 |
| DD125000A5 (en) | 1977-03-23 |
| AU499936B2 (en) | 1979-05-03 |
| NO761536L (en) | 1976-11-08 |
| NO142871C (en) | 1980-11-05 |
| IT1037842B (en) | 1979-11-20 |
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