CN107982970B - Filter plate for plate-frame filter pressing device and preparation method of filter structure of filter plate - Google Patents

Abstract

The invention discloses a filter plate for a plate-frame filter pressing device and a preparation method of a filter structure of the filter plate. The filter plate for the plate-frame filter pressing device comprises a filter structure, wherein the filter structure comprises a porous metal supporting net, porous metal supporting surfaces distributed on two sides of the porous metal supporting net and a metal filter membrane arranged on at least one porous metal supporting surface, and the area of the metal filter membrane is more than or equal to that of a filter pressing surface; the filter plate further comprises a conductive structure, wherein the conductive structure comprises a conductive sheet arranged on the upper portion of the porous metal supporting net, and the conductive sheet is fixedly connected with the porous metal supporting net. The filter structure of the invention is made of metal, and has higher corrosion resistance and mechanical strength and longer service life compared with the traditional filter cloth. The invention is additionally provided with a conductive structure, and positive charges or negative charges can be applied to the filter plate, so that the sludge can be dehydrated through electroosmosis while being subjected to filter pressing, and the dehydration effect is obviously improved.

Description

Filter plate for plate-frame filter pressing device and preparation method of filter structure of filter plate

Technical Field

The invention relates to the technical field of plate-and-frame filter pressing, in particular to a preparation method of a filter plate for a plate-and-frame filter pressing device and a filter structure of the filter plate.

Background

With the rapid increase of urban domestic sewage output and the large-scale construction and operation of sewage treatment plants, urban sludge production is rapidly increased, and it is predicted that urban sludge production in China is increased from 5300 ten thousand tons/a in 2015 to 7500 ten thousand tons/a in 2020, but at present, the sludge disposal rate of China including a sludge landfill treatment mode is only about 25%, and a large amount of sludge is not properly disposed.

The sludge produced by a sewage treatment plant is solid-liquid suspended matter, the water content of the sludge is up to 95-98%, the water in the sludge mainly comprises interstitial water, capillary water, surface adsorption water and internal binding water, wherein the interstitial water accounts for about 70%, the surface adsorption water accounts for about 5%, the internal binding water accounts for about 5%, and the rest is capillary water; the water content of the sludge is different, the sludge is in a fluid state when the water content is more than 85%, is in a plastic state when the water content is 65-85%, and is in a solid state when the water content is less than 60%.

The higher water content brings great difficulty to the subsequent dehydration, digestion, transportation and comprehensive utilization of the sludge, and severely restricts the treatment and disposal of the sludge. The dewatering of sludge is the most expensive step in the sludge treatment cost, and common sludge treatment technologies mainly comprise land utilization, deep landfill, incineration power generation and the like. Due to the increasingly intense urban land resources and environmental problems caused by sludge disposal, the land utilization and landfill ratio gradually decreases, and the incineration treatment ratio gradually increases, and the method becomes a main sludge disposal means in developed countries. The sludge incineration treatment has strict requirements on the water content in the sludge, and the high water content can lead to low incineration efficiency, high incinerator corrosion, low heat value utilization rate and the like. Therefore, the sludge must be dewatered before the sludge incineration is the final disposal means.

At present, the sludge dewatering process mainly comprises three steps of natural evaporation, thermal dewatering and mechanical dewatering, wherein the natural evaporation is to spread the concentrated sludge into a thin layer on the ground, so that the water content in the sludge is naturally evaporated, the method can reduce the water content of the sludge to about 65%, the sludge in the state has no fluidity and can be used as fertilizer, and the method has the defects of large occupied area, great influence of climate and poor sanitary condition and has poor effect on certain sludge which is not easy to dewater. The heat drying is to put the sludge into a closed container for heating, dry the sludge by utilizing heat energy at a certain temperature and pressure, destroy microorganism cells in the sludge, hydrolyze macromolecular organic matters and the like. Mechanical dewatering mainly refers to pressure filtration, centrifugal separation, rotary extrusion and the like, wherein the pressure filtration uses pressure difference at two sides of a filter medium as driving force to force moisture in sludge to pass through the filter medium to form filtrate so as to trap solid substances to form a filter cake, the centrifugal separation realizes separation of the solid substances and liquid phase by using centrifugal force, and the rotary extrusion realizes removal of the moisture in the sludge by extruding the sludge by using a gradually narrowed spiral channel. For common mechanical dehydration, the water content of the dehydrated sludge still reaches more than 80%, further deep dehydration is needed for disposal, and the transportation cost and disposal cost are still high.

Disclosure of Invention

The invention firstly provides a preparation method of a filter plate for a plate-and-frame filter pressing device and a corresponding filter structure, and secondly provides a plate-and-frame filter pressing unit and the plate-and-frame filter pressing device using the same, so as to solve the technical problems of high cost and difficult deep dehydration in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a filter plate for a plate and frame filter press apparatus. The filter plate for the plate-frame filter pressing device comprises a filter structure, wherein the filter structure comprises a porous metal supporting net, porous metal supporting surfaces distributed on two sides of the porous metal supporting net and a metal filter membrane arranged on at least one porous metal supporting surface, and the area of the metal filter membrane is more than or equal to that of a filter pressing surface; the filter plate further comprises a conductive structure, wherein the conductive structure comprises a conductive sheet arranged on the upper portion of the porous metal supporting net, and the conductive sheet is fixedly connected with the porous metal supporting net.

Firstly, the filtering structure is made of metal, and compared with the traditional filter cloth, the filtering structure has higher corrosion resistance and mechanical strength and longer service life. Secondly, the filter structure has a multi-layer composite structure, the porous metal supporting net plays a good supporting role, and the porous metal supporting surface not only has a supporting role and a filtering role, but also can provide a flat surface, is beneficial to sealing and improves the filter pressing efficiency. In addition, the filtering structure is a metal structure, and the filtering plate is additionally provided with a conductive structure, so that positive charges or negative charges can be applied to the filtering plate, the sludge can be dehydrated through electroosmosis while being subjected to filter pressing, and the dehydration effect is obviously improved. When no electric charge is applied, the sludge is only subjected to mechanical action, but the mechanical action can only remove surface adsorbed water and capillary water, so that bound water and interstitial water are difficult to remove, and sludge floccules are mutually close to be compacted, the compaction is realized when the pressure is higher, and water is more difficult to flow out, so that the requirement of deep dehydration cannot be met by adopting single mechanical dehydration; electroosmosis is a liquid-solid separation technology using an electric field as a driving force, and the principle is that under the action of the electric field, sludge particles can move to an anode due to negative charges on the surfaces of the sludge particles, and water molecules can move to a cathode due to partial positive charges under the driving of the electric field, so that the sludge is dehydrated. Therefore, the invention can remarkably improve the dehydration effect by combining the mechanical press filtration of the plate frame and electroosmosis through a simple structure.

Further, the thickness of the porous metal supporting net is 0.5-2 mm, and the porosity is more than or equal to 60%. Thus, the porous metal support net with the parameters has the best support effect and good conductivity.

Further, the thickness of the porous metal supporting surface is 0.2-1 mm, the porosity is more than or equal to 50%, and the pore diameter is 20-50 mu m. Thus, the porous metal support surface with the parameters has a flat surface, good support effect, good conductivity and certain filtering effect.

Further, the thickness of the metal filtering membrane is 0.01-0.1 mm, the porosity is more than or equal to 40%, and the aperture is 1-10 mu m. Therefore, the metal filtering membrane with the parameters has the advantages of large flux, low resistance, high precision and good conductivity, and can effectively intercept solid particles in sludge.

Further, the metal filtering membrane is arranged on the two porous metal supporting surfaces; therefore, after the filter plate is used for a period of time, the filter plate can be turned back and forth to continue to be used, and the service life is longer.

Further, the conducting strip is made of copper; the two side surfaces of the upper part of the porous metal supporting net are provided with the conductive sheets; the conducting strip is connected with the porous metal supporting net by adopting a bolt assembly. Thus, a good conduction effect is ensured.

Further, the metal filtering membrane and the porous metal supporting surface are porous materials taking solid solution alloy, face-centered cubic metal simple substance or body-centered cubic metal simple substance as matrix phase. Therefore, the metal filtering membrane has excellent corrosion resistance and mechanical strength, and longer service life.

Further, the height of the porous metal supporting net is higher than that of the porous metal supporting surface, and the side length of the porous metal supporting surface is longer than that of the metal filtering membrane; and the sludge flow channel and the filtrate flow channel which pass through the porous metal supporting net and the porous metal supporting surface are also included. Thus, the material can be reasonably utilized on the premise of ensuring good conductivity and filtering effect. The metal filtering membrane mainly plays a filtering role, and the area of the metal filtering membrane is matched with that of the filter pressing surface, so that the sludge flow channel and the filtrate flow channel only pass through the porous metal supporting net and the porous metal supporting surface, and materials can be saved. Of course, it is also possible to make the size of the metal filtration membrane coincide with the size of the porous metal support surface.

In order to achieve the above object, according to one aspect of the present invention, there is next provided a method of manufacturing a filter structure. The preparation method of the filter structure comprises the following steps:

(1) Preparing a paste mixture from an adhesive, a dispersing agent and raw material powder forming the porous metal supporting surface, then taking the porous metal supporting net as a supporting body, pressing the paste mixture on the surface of the porous metal supporting net by adopting pressure forming to form a first film layer, and drying to obtain a first pressed compact; sintering the first pressed compact to convert the first film layer into the porous metal supporting surface;

(2) Preparing a slurry from an adhesive, a dispersing agent and raw material powder forming the metal filtering membrane, then taking the porous metal supporting surface as a supporting body, attaching the slurry to the surface of the porous metal supporting surface to form a second membrane layer, and drying to obtain a second pressed compact; and sintering the second pressed compact to convert the second membrane layer into the metal filtering membrane, thereby obtaining the filtering structure.

The porous metal supporting net and the porous metal supporting surface are chemically combined by adopting powder metallurgy, so that the porous metal supporting net and the porous metal supporting surface are stronger in binding force and are not easy to fall off. The thickness of the porous metal supporting surface is far greater than that of the metal filtering membrane, and the aperture of the porous metal supporting surface is far smaller than that of the metal filtering membrane, so that the membrane layer manufacturing method is adopted, the process is simple, and the parameter requirements are conveniently met.

Further, the metal filtering membrane and the porous metal supporting surface are porous materials taking solid solution alloy, face-centered cubic metal simple substance or body-centered cubic metal simple substance as matrix phase. Therefore, the metal filtering membrane has excellent corrosion resistance and mechanical strength, and longer service life.

In order to achieve the above object, according to another aspect of the present invention, there is first provided a plate and frame filter press unit. The plate frame filter pressing unit comprises a first filter plate, a mud guide plate, a second filter plate, a liquid guide plate, a sludge flow channel and a filtrate flow channel which penetrate through the first filter plate, the mud guide plate, the second filter plate and the liquid guide plate, wherein a sludge cavity is formed between the first filter plate and the second filter plate, a filtrate cavity is formed between the second filter plate and the liquid guide plate, sludge in the sludge flow channel enters the sludge cavity through mud guide holes on the inner side of the mud guide plate, filtrate in the filtrate cavity flows into the filtrate flow channel from the liquid guide holes on the liquid guide plate, and the first filter plate and the second filter plate comprise a filtering structure and a conductive structure which are made of metal materials; the sludge flow channel and the filtrate flow channel are positioned on the outer side of the sealing structure, and the sludge cavity and the filtrate cavity are positioned on the inner side of the sealing structure.

Because the deformability of the filtering structure made of metal materials is lower than that of the traditional filter cloth, the sealing structure is arranged, so that the mud guiding plate, the filtering plate and the liquid guiding plate can be tightly sealed under the action of pressure, and the sealing structure can play a good sealing role even under the pressure of 0.1-15 MPa. Therefore, the plate-and-frame filter pressing unit has a simple structure, and the combination of mechanical dehydration and electroosmosis dehydration of the sludge is realized through the improvement of the plate-and-frame filter pressing unit, so that the purpose of deep dehydration of the sludge is achieved.

Further, the filtering structure comprises a porous metal supporting net, porous metal supporting surfaces distributed on two side surfaces of the porous metal supporting net and two metal filtering films respectively arranged on the two porous metal supporting surfaces, and the area of each metal filtering film is larger than or equal to that of each filtering surface. From this, this filtration has multilayer composite construction, and this porous metal supporting network plays good supporting role, and porous metal supporting surface not only has supporting role and filtering role, can also provide smooth surface, helps sealed, promotes filter-pressing efficiency.

Further, the conductive structure comprises a conductive sheet arranged at the upper part of the porous metal supporting net, and the conductive sheet is fixedly connected with the porous metal supporting net. Thereby, the conductivity of the filter plate is improved.

Further, the thickness of the mud guiding plate is smaller than that of the liquid guiding plate. In the electro-osmotic dehydration process, the voltage applied to the filter cake in the mud guiding plate can form a certain voltage gradient on the filter cake, so that the filter cake and the mud guiding plate cannot be too thick, otherwise, the electro-osmotic deep dehydration of the sludge is not facilitated.

Further, the liquid guide plate is provided with bulges, and liquid guide channels are formed between adjacent bulges; whereby the filtrate is also allowed to flow out when the seal is pressed. The protrusions are bosses, thereby reducing mechanical damage to the metal filtration membrane by the protrusions.

Further, the filter plate further comprises a cleaning channel penetrating through the first filter plate, the mud guide plate, the second filter plate and the liquid guide plate. Thus, the filtration flux of the filtration structure can be quickly restored after a certain time.

Further, the sealing structure comprises a groove and a sealing ring arranged in the groove, the thickness of the sealing ring is 5-15 mm, and the sealing ring is made of silicon rubber or fluororubber. Therefore, the sealing effect is good and the corrosion resistance is good.

Further, the thickness of the porous metal supporting net is 0.5-2 mm, and the porosity is more than or equal to 60%; the thickness of the porous metal supporting surface is 0.2-1 mm, the porosity is more than or equal to 50%, and the aperture is 20-50 mu m; the thickness of the metal filtering membrane is 0.01-0.1 mm, the porosity is more than or equal to 40%, and the aperture is 1-10 mu m.

In order to achieve the above object, according to another aspect of the present invention, there is next provided a plate and frame filter press apparatus. The plate-and-frame filter pressing device comprises a thrust plate and a plurality of filter pressing units which are sequentially arranged behind the thrust plate, wherein the filter pressing units are the plate-and-frame filter pressing units; the filtrate cavity is formed between the first filter plate of the later plate-and-frame filter pressing unit and the liquid guide plate of the former plate-and-frame filter pressing unit; the filter press unit further comprises an electrifying system for enabling the first filter plate and the second filter plate of each plate-and-frame filter press unit to have opposite charges and enabling the first filter plate and the second filter plate on two sides of each liquid guide plate to have the same charges. Therefore, the plate-and-frame filter pressing device can be used for carrying out mechanical filter pressing dehydration and electroosmosis deep dehydration on the sludge, and the water content of the obtained filter cake is obviously reduced. Through verification, the plate-and-frame filter pressing device is adopted to treat sludge, and the water content of the obtained filter cake can be reduced to below 60%.

Therefore, the unique multi-layer metal filter structure for the filter plate of the plate-and-frame filter pressing device not only can ensure that the filter plate has certain strength, but also can uniformly power up through the conductive structure, can also ensure sealing and filtering precision, and has the dual effects of mechanical press filtration dehydration and sludge infiltration dehydration. The plate-frame filter pressing unit has a simple structure, and the plate-frame filter pressing device formed by the plate-frame filter pressing unit can carry out mechanical dehydration and electroosmosis dehydration on sludge, thereby meeting the requirement of deep dehydration of the sludge and having the advantages of low energy consumption and long service life.

The invention is further described below with reference to the drawings and detailed description. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which form a part hereof, are shown by way of illustration and not of limitation, and in which are shown by way of illustration and description of the invention. In the drawings:

FIG. 1 is a front view of a filter plate for a frame filter press apparatus of the present invention.

Fig. 2 is a cross-sectional view taken along A-A of fig. 1.

Fig. 3 is a schematic structural diagram of a plate and frame filter press unit according to the present invention.

Fig. 4 is a front view of the mud guiding plate of fig. 3.

Fig. 5 is a D-D cross-sectional view of fig. 4.

Fig. 6 is a partial cross-sectional view of fig. 4.

Fig. 7 is a front view of the liquid guide plate of fig. 3.

Fig. 8 is a B-B cross-sectional view of fig. 7.

Fig. 9 is a C-C cross-sectional view of fig. 7.

Fig. 10 is a partial cross-sectional view of fig. 7.

FIG. 11 is a schematic diagram of a plate and frame filter press apparatus according to the present invention.

The relevant marks in the drawings are as follows:

11: a porous metal support mesh;

12: a porous metal support surface;

13: a metal filtration membrane;

21: a conductive sheet;

22: a bolt assembly;

31: a sludge flow passage;

32: a filtrate flow channel;

33: cleaning the channel;

41: a first filter plate;

51: a mud guiding plate;

42: a second filter plate;

52: a liquid guide plate;

510: a mud guiding hole;

520: a liquid guiding hole;

521: a protrusion;

6: a seal ring;

7: a thrust plate;

8: and a plate frame filter pressing unit.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be noted in particular that:

the technical solutions and technical features provided in the sections including the following description in the present invention may be combined with each other without conflict.

In addition, the embodiments of the present invention referred to in the following description are generally only some, but not all, embodiments of the present invention. Therefore, all other embodiments, which can be made by one of ordinary skill in the art without undue burden, are intended to be within the scope of the present invention, based on the embodiments of the present invention.

Terms and units in relation to the present invention. The terms "comprising," "having," and any variations thereof in the description and claims of the invention and in the relevant sections are intended to cover a non-exclusive inclusion. The term "filtration surface" refers to a two-phase interface in direct contact with the filtration system that is effective to intercept the passage of solid particulates while allowing the passage of filtrate.

Example 1

The plate and frame filter press apparatus shown in fig. 1-2 uses a filter plate comprising a filter structure and a conductive structure.

The filtering structure comprises a porous metal supporting net 11, porous metal supporting surfaces 12 distributed on two sides of the porous metal supporting net 11, and two metal filtering films 13 respectively arranged on the two porous metal supporting surfaces 12, wherein the area of each metal filtering film 13 is more than or equal to that of each filtering surface;

the height of the porous metal support net 11 is higher than that of the porous metal support surface 12, and the width of the porous metal support net 11 is equal to that of the porous metal support surface 12; the side length of the porous metal supporting surface 12 is longer than that of the metal filtering membrane 13; also included are sludge flow channels 31 and filtrate flow channels 32 through the porous metal support mesh 11 and porous metal support surface 12.

The thickness of the porous metal supporting net 11 is 1mm, the porosity is more than or equal to 60%, the aperture is 100 mu m, and the porous metal supporting net is made of 304 stainless steel screen.

The thickness of the porous metal supporting surface 12 is 0.6mm, the porosity is more than or equal to 50%, and the pore diameter is 30 mu m.

The thickness of the metal filtering membrane 13 is 0.05mm, the porosity is more than or equal to 40%, and the pore diameter is 5 mu m.

The conductive structure comprises conductive sheets 21 arranged on two side surfaces of the upper part of the porous metal support net 11, and the conductive sheets 21 are connected with the porous metal support net 11 by bolt assemblies 22. The conductive sheet 21 is made of copper, and the length of the conductive sheet 21 is matched with the width of the porous metal support net 11.

The metal filtering membrane 13 and the porous metal supporting surface 12 are porous materials which take solid solution alloy, face-centered cubic metal simple substance or body-centered cubic metal simple substance as matrix phase.

The plate-and-frame filter pressing unit 8 shown in fig. 3 comprises a first filter plate 41, a mud guide plate 51 (shown in fig. 4-6), a second filter plate 42 and a liquid guide plate 52 (shown in fig. 7-10) which are sequentially arranged, and a sludge flow channel 31 and a filtrate flow channel 32 which penetrate through the first filter plate 41, the mud guide plate 51, the second filter plate 42 and the liquid guide plate 52, wherein a sludge cavity is formed between the first filter plate 41 and the second filter plate 42, a filtrate cavity is formed between the second filter plate 42 and the liquid guide plate 52, sludge in the sludge flow channel 31 enters the sludge cavity through a mud guide hole 510 on the inner side of the mud guide plate 51, and filtrate in the filtrate cavity flows into the filtrate flow channel 32 from a liquid guide hole 520 on the liquid guide plate 52, and the first filter plate 41 and the second filter plate 42 are filter plates shown in fig. 1-2; the liquid guide plate 52 and the mud guide plate 51 are provided with sealing structures with matched sizes, the sludge flow channel 31 and the filtrate flow channel 32 are positioned on the outer sides of the sealing structures, and the sludge cavity and the filtrate cavity are positioned on the inner sides of the sealing structures.

The thickness of the mud guiding plate 51 is smaller than that of the liquid guiding plate 52.

The liquid guide plate 52 is provided with protrusions 521, and liquid guide channels are formed between adjacent protrusions 521; the protrusions 521 are bosses.

Also included are cleaning channels 33 extending through the first filter plate 41, the mud guide plate 51, the second filter plate 42 and the liquid guide plate 52. The sludge flow channel 31 and the filtrate flow channel 32 are respectively positioned at two ends below the plate and frame filter pressing unit 8. The number of the cleaning channels 33 is two, and the cleaning channels are respectively positioned at two ends above the plate-and-frame filter pressing unit 8.

The sealing structure comprises a groove and a sealing ring 6 arranged in the groove, the thickness of the sealing ring 6 is 10mm, and the sealing ring 6 is made of silicone rubber. The height of the seal ring 6 is higher than the height of the protrusions 521.

The plate-and-frame filter pressing device shown in fig. 11 comprises a thrust plate 7 and four plate-and-frame filter pressing units 8 shown in fig. 3 which are sequentially arranged behind the thrust plate 7, wherein a filtrate cavity is formed between a first filter plate 41 of the later plate-and-frame filter pressing unit 8 and a liquid guide plate 52 of the former plate-and-frame filter pressing unit 8; also included is an energization system that charges the first filter plate 41 and the second filter plate 42 of each frame filter press unit 8 oppositely and charges the first filter plate 41 and the second filter plate 42 on both sides of each permeate guide plate 52 equally.

The main difference between the thrust plate 7 and the liquid guide plate 52 is that the surface of the thrust plate 7 facing away from the first filter plate 41 is not provided with protrusions 521. The main difference between the last liquid guiding plate 52 and the other liquid guiding plates 52 is that the surface of the last liquid guiding plate 52 facing away from the second filter plate 42 is not provided with protrusions 521 and that the sludge flow channel 31 and the filtrate flow channel 32 are blind holes.

The preparation method of the filter structure comprises the following steps:

(1) Preparing a paste mixture from an adhesive, a dispersing agent and raw material powder forming the porous metal supporting surface 12, then taking the porous metal supporting net 11 as a supporting body, pressing the paste mixture on the surface of the porous metal supporting net 11 by adopting pressure forming to form a first film layer, and drying and pressing to obtain a first pressed blank; sintering the first green compact to convert the first film layer into the porous metal support surface 12;

(2) Preparing a slurry from an adhesive, a dispersing agent and raw material powder forming the metal filtering membrane 13, then taking the porous metal supporting surface 12 as a supporting body, attaching the slurry to the surface of the porous metal supporting surface 12 to form a second membrane layer, and drying and pressing to obtain a second pressed compact; and sintering the second pressed compact to convert the second membrane layer into the metal filtering membrane 13, thereby obtaining the filtering structure.

Wherein, step (1) may further specifically be as follows:

the preparation process of the pasty mixture comprises the following steps: firstly, uniformly mixing Ni powder and Cu powder to form raw material powder, wherein the mass of the Cu powder is 30% of that of the raw material powder, and then preparing a pasty mixture by taking ethanol as a dispersing agent and PVB as a binder according to the proportion of 30g PVB and 500g raw material powder in 100ml ethanol solution; pressing: rolling at a rolling speed (roll rotation speed) of 200r/min under 25 MPa; the sintering process comprises the following steps: the sintering temperature is gradually increased to 550 ℃ and kept for 90min, and then the temperature is directly increased to 1130 ℃ at the heating rate of 6 ℃/min and kept for 180min.

Step (2) may further be specifically as follows:

the preparation process of the slurry comprises the following steps: uniformly mixing Ni powder and Cu powder to form raw material powder, wherein the mass of the Cu powder is 30% of that of the raw material powder, then using ethanol as a dispersing agent and PVB as a binder, adding PVB into ethanol according to the mass ratio of PVB to ethanol of 2.5:100 to prepare PVB solution, adding raw material powder into PVB solution according to the mass ratio of 25g of raw material powder per 100ml of ethanol, and stirring to fully and uniformly disperse the raw material powder to obtain viscous suspension; pressing: rolling at a rolling speed (roll rotation speed) of 600r/min under 10 MPa; the sintering process comprises the following steps: the sintering temperature is gradually increased to 550 ℃ and kept at the temperature for 90min, and then the temperature is directly increased to 1130 ℃ at the heating rate of 6 ℃ per min and kept at the temperature for 180min.

Example 2

Compared with embodiment 1, this embodiment has the following differences: the metal filtration membrane 13 is provided only on one of the porous metal support surfaces 12.

The content of the present invention is described above. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. Based on the foregoing, all other embodiments that may be obtained by one of ordinary skill in the art without undue burden are within the scope of the present invention.

Claims (7)

1. The filter plate for the plate-and-frame filter pressing device comprises a filter structure and is characterized in that: the filtering structure comprises a porous metal supporting net (11), porous metal supporting surfaces (12) distributed on two sides of the porous metal supporting net (11) and metal filtering films (13) arranged on the two porous metal supporting surfaces (12), wherein the area of each metal filtering film (13) is larger than or equal to that of each filtering surface; the filter plate further comprises a conductive structure, wherein the conductive structure comprises a conductive sheet (21) arranged at the upper part of the porous metal supporting net (11), and the conductive sheet (21) is fixedly connected with the porous metal supporting net (11); the thickness of the porous metal supporting net (11) is 0.5-2 mm; the thickness of the porous metal supporting surface (12) is 0.2-1 mm; the thickness of the metal filtering membrane (13) is 0.01-0.1 mm;

the conductive sheet (21) is made of copper; the two side surfaces of the upper part of the porous metal supporting net (11) are provided with the conducting plates (21); the conducting strip (21) is connected with the porous metal supporting net (11) by adopting a bolt component (22);

the metal filtering membrane (13) and the porous metal supporting surface (12) are porous materials taking solid solution alloy, face-centered cubic metal simple substance or body-centered cubic metal simple substance as a matrix phase.

2. The filter plate for a plate and frame filter press apparatus according to claim 1, wherein: the porosity of the porous metal supporting net (11) is more than or equal to 60 percent.

3. The filter plate for a plate and frame filter press apparatus according to claim 1, wherein: the porosity of the porous metal supporting surface (12) is more than or equal to 50 percent, and the pore diameter is 20-50 mu m.

4. The filter plate for a plate and frame filter press apparatus according to claim 1, wherein: the porosity of the metal filtering membrane (13) is more than or equal to 40 percent, and the pore diameter is 1-10 mu m.

5. The filter plate for a plate and frame filter press apparatus according to claim 1, wherein: the height of the porous metal supporting net (11) is higher than that of the porous metal supporting surface (12), and the side length of the porous metal supporting surface (12) is larger than that of the metal filtering membrane (13); also comprises a sludge flow channel (31) and a filtrate flow channel (32) which pass through the porous metal support net (11) and the porous metal support surface (12).

6. The process for producing a filter plate for a plate-and-frame filter press apparatus according to any one of claims 1 to 5, characterized in that: the preparation of the filter structure of the filter plate comprises the following steps:

(1) Preparing a paste mixture from an adhesive, a dispersing agent and raw material powder forming the porous metal supporting surface (12), then taking the porous metal supporting net (11) as a supporting body, pressing the paste mixture on the surface of the porous metal supporting net (11) by adopting pressure forming to form a first film layer, and drying to obtain a first pressed blank; sintering the first green compact to convert the first film layer into the porous metal support surface (12);

(2) Preparing a slurry from an adhesive, a dispersing agent and raw material powder forming the metal filtering membrane (13), then taking the porous metal supporting surface (12) as a supporting body, attaching the slurry to the surface of the porous metal supporting surface (12) to form a second membrane layer, and drying to obtain a second pressed compact; sintering the second pressed compact to convert the second membrane layer into the metal filtering membrane (13), and obtaining the filtering structure.

7. The method for preparing the filter plate for the plate-and-frame filter pressing device according to claim 6, wherein: the metal filtering membrane (13) and the porous metal supporting surface (12) are porous materials taking solid solution alloy, face-centered cubic metal simple substance or body-centered cubic metal simple substance as a matrix phase.