A vertical filter press filter cloth regeneration system and method for an alumina plant

Abstract

The present invention belongs to the field of chemical engineering technology, and particularly relates to a filter cloth regeneration system and method for a vertical filter press in an alumina plant. The system includes: the hot water outlet of an evaporation unit is connected to a hot water tank through a pipeline, the outlet of the hot water tank is connected to the feed inlet of the vertical filter press through a pipeline with a centrifugal pump and a pneumatic hot water valve, the feed inlet of the vertical filter press is also connected to the feed inlet of a reaction tank through a pipeline with a pneumatic return valve, the filtrate outlet of the vertical filter press is connected to a return water tank through a pipeline with a pneumatic return water valve, and the return water tank is connected to a sedimentation device through a pipeline; by utilizing the characteristic that sodium oxalate is easily soluble in hot water, the present invention introduces high-temperature hot water into the vertical filter press, replaces the mother liquor to be filtered with hot water, further dissolves a small part of sodium oxalate in the pores of the filter cloth, and the dissolved sodium oxalate leaves the filter cloth along with the hot water, ensuring the permeability of the pores of the filter cloth.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and particularly relates to a filter cloth regeneration system and method for a vertical filter press in an alumina plant. Background Art

[0002] With the large-scale use of imported bauxite in domestic alumina plants to produce alumina, the problem of organic matter has become increasingly prominent. In the alumina system, as sodium oxalate continuously accumulates in the solution, it will gradually have a serious impact on the production process, mainly manifested in: 1. The viscosity of the solution increases, and it is extremely easy to generate foam, resulting in a low full-tank and full-tank rate and a decline in the effect of related heat exchange equipment; 2. After sodium oxalate precipitates, it adheres to the gaps or surfaces of aluminum hydroxide, seriously hindering the agglomeration and growth of crystals, and increasing secondary nucleation. Eventually, the product particle size is refined, resulting in a serious impact on product quality; 3. It is extremely easy to block the filter cloth holes of vertical and horizontal plate filter presses, leading to a reduction in filtration effect and a sharp drop in production capacity; 4. It is easy to form scale inside the equipment, reducing the heat transfer coefficient, increasing energy consumption, and easily peeling off, resulting in non-stop operation of various equipment.

[0003] The vertical fully automatic filter press is a new type, efficient, energy-saving and environmentally friendly solid-liquid separation equipment. The equipment uses the pressure of the pump, the gravity of the material and the extrusion of the rubber diaphragm to quickly filter the slurry through the filter cloth, so as to achieve efficient solid-liquid separation. The use environment of this filter press is the sodium oxalate removal system in the alumina plant. Due to the high concentration of sodium oxalate in the removal system, it precipitates and accumulates in the pores of the filter cloth, resulting in a serious decline in the filtration performance of the filter cloth. At the end of filtration, its throughput is only a few cubic meters. Traditional filter cloth cleaning can only clean the residual substances on the surface of the filter cloth and cannot clean the pores of the filter cloth. The cleaning effect is poor, and the filter cloth regeneration effect is seriously insufficient.

[0004] As the only equipment for discharging organic matter, due to the poor filter cloth regeneration effect, the filter press cannot effectively discharge the sodium oxalate precipitated from the removal system in time and effectively, seriously restricting the stability of the alumina system production. Summary of the Invention

[0005] The present invention provides a filter cloth regeneration system and method for a vertical filter press in an alumina plant in view of the above problems.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A filter cloth regeneration system for a vertical filter press in an alumina plant, comprising a vertical filter press. The feed inlet of the vertical filter press is connected to the outlet of a discharge tank through a pipeline with a centrifugal pump and a pneumatic feed valve. The feed inlet of the discharge tank is connected to the outlet of a reaction tank through a pipeline. The feed inlet of the reaction tank is connected to the mother liquor outlet of an evaporation unit through a pipeline. The filtrate outlet of the vertical filter press is connected to a filtrate tank through a pipeline with a pneumatic filtrate valve. The outlet of the filtrate tank is connected to a preparation unit through a pipeline with a centrifugal pump. The hot water outlet of the evaporation unit is connected to a hot water tank through a pipeline. The outlet of the hot water tank is connected to the feed inlet of the vertical filter press through a pipeline with a centrifugal pump and a pneumatic hot water valve. The feed inlet of the vertical filter press is also connected to the feed inlet of the reaction tank through a pipeline with a pneumatic return valve. The filtrate outlet of the vertical filter press is connected to a return water tank through a pipeline with a pneumatic return water valve. The return water tank is connected to a sedimentation device through a pipeline.

[0008] Further, it also includes an air compressor. The gas outlet of the air compressor is connected to the feed inlet of the vertical filter press through a pipeline with a pneumatic air blowing valve.

[0009] Still further, a dryer is provided between the air compressor and the vertical filter press for drying the air entering the vertical filter press.

[0010] A method for regenerating the filter cloth of a vertical filter press in an alumina plant of a filter cloth regeneration system, including a hot water cloth washing operation and an air blowing filter cloth operation;

[0011] The hot water cloth washing operation includes the following steps:

[0012] 1) Close the pneumatic feed valve, the pneumatic hot water valve and the pneumatic air blowing valve, open the pneumatic return valve, empty the mother liquor in the vertical filter press, and close the pneumatic return valve after emptying;

[0013] 2) Open the pneumatic hot water valve and the pneumatic return water valve, and close all the pneumatic feed valve, the pneumatic filtrate valve, the pneumatic return valve and the pneumatic air blowing valve;

[0014] 3) The hot water produced by the evaporation unit enters the hot water tank through a pipeline, and then is sent into the vertical filter press through a pipeline with a centrifugal pump. The hot water passes through the filter cloth and finally enters the return water tank through the pneumatic return water valve. The hot water in the return water tank is transported to the sedimentation device through a pipeline;

[0015] The air blowing filter cloth operation includes the following steps:

[0016] 1) Close the pneumatic feed valve, the pneumatic hot water valve and the pneumatic air blowing valve, open the pneumatic return valve, empty the hot water in the vertical filter press, and close the pneumatic return valve after emptying;

[0017] 2) Open the pneumatic air blowing valve and the pneumatic return water valve, and close all the pneumatic feed valve, the pneumatic filtrate valve, the pneumatic hot water valve and the pneumatic return material valve;

[0018] 3) The compressed air generated by the air compressor is dried by the dryer. The dried compressed air enters the vertical pressure filter through the pneumatic air blowing valve. The compressed air penetrates through the filter cloth and finally enters the return water tank through the pneumatic return water valve. The compressed air in the return water tank gradually returns to the atmosphere.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The present invention utilizes the characteristic that sodium oxalate is easily soluble in hot water. High-temperature hot water is introduced into the vertical pressure filter, and the mother liquor to be filtered is replaced with hot water to further dissolve a small part of sodium oxalate in the pores of the filter cloth. The dissolved sodium oxalate leaves the filter cloth with the hot water, ensuring the permeability of the pores of the filter cloth;

[0021] After the present invention uses hot water to clean the filter cloth, the water quality becomes poor and cannot be reused. To avoid non-production water entering the process, it directly enters the sedimentation equipment as washing water for sedimentation and does not enter the evaporation or organic matter removal system, causing less damage to the production conditions;

[0022] After the present invention uses hot water to clean the filter cloth, the filter cloth is regenerated again by compressed air. Specifically, by utilizing the characteristic that the high-pressure air has strong penetration ability, the remaining part of sodium oxalate in the filter cloth is blown out of the filter cloth, once again ensuring the regeneration effect of the filter cloth;

[0023] Under the regeneration effect of hot water and high-pressure air on the filter cloth, the filter cloth can maintain the best filtration performance for a long time, further improving the production capacity of the vertical pressure filter, and then ensuring the stable operation of the removal system, providing strong support for the production system using imported ore to produce alumina. Brief Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the present invention;

[0025] In the figure, vertical pressure filter - 1, centrifugal pump - 2, pneumatic feed valve - 3, discharge tank - 4, reaction tank - 5, evaporation unit - 6, pneumatic filtrate valve - 7, filtrate tank - 8, blending unit - 9, hot water tank - 10, pneumatic hot water valve - 11, pneumatic return material valve - 12, pneumatic return water valve - 13, return water tank - 14, sedimentation equipment - 15, air compressor - 16, pneumatic air blowing valve - 17, dryer - 18. Detailed Embodiments

[0026] In order to further elaborate the technical solution of the present invention, the present invention will be further described below through embodiments.

[0027] Such as Figure 1As shown in the figure, an alumina plant vertical filter press filter cloth regeneration system includes a vertical filter press 1 and an air compressor 16. The feed inlet of the vertical filter press 1 is connected to the outlet of a discharge tank 4 through a pipeline with a centrifugal pump 2 and a pneumatic feed valve 3. The feed inlet of the discharge tank 4 is connected to the outlet of a reaction tank 5 through a pipeline. The feed inlet of the reaction tank 5 is connected to the mother liquor outlet of an evaporation unit 6 through a pipeline. The filtrate outlet of the vertical filter press 1 is connected to a filtrate tank 8 through a pipeline with a pneumatic filtrate valve 7. The outlet of the filtrate tank 8 is connected to a blending unit 9 through a pipeline with a centrifugal pump 2. The hot water outlet of the evaporation unit 6 is connected to a hot water tank 10 through a pipeline. The outlet of the hot water tank 10 is connected to the feed inlet of the vertical filter press 1 through a pipeline with a centrifugal pump 2 and a pneumatic hot water valve 11. The feed inlet of the vertical filter press 1 is also connected to the feed inlet of the reaction tank 5 through a pipeline with a pneumatic return valve 12. The filtrate outlet of the vertical filter press 1 is connected to a return water tank 14 through a pipeline with a pneumatic return water valve 13. The return water tank 14 is connected to a sedimentation device 15 through a pipeline. The gas outlet of the air compressor 16 is connected to a dryer 18 through a pipeline. The outlet of the dryer 18 is connected to the feed inlet of the vertical filter press 1 through a pipeline with a pneumatic air blowing valve 17.

[0028] A method for regenerating the filter cloth of a vertical filter press in an alumina plant's filter cloth regeneration system includes a hot water cloth washing operation and an air blowing filter cloth operation;

[0029] The hot water cloth washing operation includes the following steps:

[0030] 1) Close the pneumatic feed valve 3, the pneumatic hot water valve 11, and the pneumatic air blowing valve 17, open the pneumatic return valve 12, empty the mother liquor in the vertical filter press 1, and then close the pneumatic return valve 12 after emptying;

[0031] 2) Open the pneumatic hot water valve 11 and the pneumatic return water valve 13, and close all the pneumatic feed valve 3, the pneumatic filtrate valve 7, the pneumatic return valve 12, and the pneumatic air blowing valve 17;

[0032] 3) The hot water produced by the evaporation unit 6 enters the hot water tank 10 through a pipeline, and then is sent into the vertical filter press 1 through a pipeline with a centrifugal pump 2. The hot water passes through the filter cloth and finally enters the return water tank 14 through the pneumatic return water valve 13. The hot water in the return water tank 14 is transported to the sedimentation device 15 through a pipeline.

[0033] The air blowing filter cloth operation includes the following steps:

[0034] 1) Close the pneumatic feed valve 3, the pneumatic hot water valve 11, and the pneumatic air blowing valve 17, open the pneumatic return valve 12, empty the hot water in the vertical filter press 1, and then close the pneumatic return valve 12 after emptying;

[0035] 2) Open the pneumatic air blowing valve 17 and the pneumatic return water valve 13, and close all the pneumatic feed valve 3, the pneumatic filtrate valve 7, the pneumatic hot water valve 11, and the pneumatic return material valve 12;

[0036] 3) The compressed air generated by the air compressor 16 is dried by the dryer 18. The dried compressed air enters the vertical filter press 1 through the pneumatic air blowing valve 17. The compressed air passes through the filter cloth and finally enters the water return tank 14 through the pneumatic return water valve 13. The compressed air in the water return tank 14 gradually returns to the atmosphere.

[0037] Filtration operation of the vertical filter press:

[0038] When the vertical filter press 1 is performing the filtration operation, the pneumatic feed valve 3 and the pneumatic filtrate valve 7 are in the open state, and the pneumatic hot water valve 11, the pneumatic return material valve 12, the pneumatic return water valve 13, and the pneumatic air blowing valve 17 are in the closed state;

[0039] The mother liquor produced by the evaporation unit 6 is sent to the reaction tank 5 through the pipeline. The mother liquor in the reaction tank 5 is transported to the discharge tank 4 through the pipeline. The mother liquor in the discharge tank 4 passes through the pipeline with the centrifugal pump 2 and enters the vertical filter press 1;

[0040] After a period of filtration, the solid filter cake is blocked by the filter cloth and discharged through the solid discharge port to become the final product. The mother liquor passes through the filter cloth and then enters the filtrate tank 8 through the pipeline, and then is transported to the blending unit 9 through the pipeline with the centrifugal pump 2 for the normal production of the alumina system.

[0041] The above shows and describes the main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

[0042] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. The narrative way of this specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for regenerating the filter cloth of a vertical filter press in an alumina plant, characterized in that: Apply an alumina plant vertical filter press filter cloth regeneration system, including a vertical filter press (1) and an air compressor (16). The feed inlet of the vertical filter press (1) is connected to the outlet of a discharge tank (4) through a pipeline with a centrifugal pump (2) and a pneumatic feed valve (3). The feed inlet of the discharge tank (4) is connected to the outlet of a reaction tank (5) through a pipeline. The feed inlet of the reaction tank (5) is connected to the mother liquor outlet of an evaporation unit (6) through a pipeline. The filtrate outlet of the vertical filter press (1) is connected to a filtrate tank (8) through a pipeline with a pneumatic filtrate valve (7). The outlet of the filtrate tank (8) is connected to a blending unit (9) through a pipeline with a centrifugal pump (2). It is characterized in that: the hot water outlet of the evaporation unit (6) is connected to a hot water tank (10) through a pipeline. The outlet of the hot water tank (10) is connected to the feed inlet of the vertical filter press (1) through a pipeline with a centrifugal pump (2) and a pneumatic hot water valve (11). The feed inlet of the vertical filter press (1) is also connected to the feed inlet of the reaction tank (5) through a pipeline with a pneumatic return valve (12). The filtrate outlet of the vertical filter press (1) is connected to a return water tank (14) through a pipeline with a pneumatic return water valve (13). The return water tank (14) is connected to a sedimentation device (15) through a pipeline. The gas outlet of the air compressor (16) is connected to the feed inlet of the vertical filter press (1) through a pipeline with a pneumatic air blowing valve (17). A dryer (18) is also provided between the air compressor (16) and the vertical filter press (1); The alumina plant vertical filter press filter cloth regeneration method includes a hot water cloth washing operation and an air blowing filter cloth operation; The hot water cloth washing operation includes the following steps: 1) Close the pneumatic feed valve (3), the pneumatic hot water valve (11) and the pneumatic air blowing valve (17), open the pneumatic return valve (12), empty the mother liquor in the vertical filter press (1), and close the pneumatic return valve (12) after emptying; 2) Open the pneumatic hot water valve (11) and the pneumatic return water valve (13), and close all the pneumatic feed valve (3), the pneumatic filtrate valve (7), the pneumatic return valve (12) and the pneumatic air blowing valve (17); 3) The hot water produced by the evaporation unit (6) enters the hot water tank (10) through a pipeline, and then is sent into the vertical filter press (1) through a pipeline with a centrifugal pump (2). The hot water passes through the filter cloth and finally enters the return water tank (14) through the pneumatic return water valve (13). The hot water in the return water tank (14) is transported to the sedimentation device (15) through a pipeline; The air blowing filter cloth operation includes the following steps: 1) Close the pneumatic feed valve (3), the pneumatic hot water valve (11) and the pneumatic air blowing valve (17), open the pneumatic return valve (12), empty the hot water in the vertical filter press (1), and close the pneumatic return valve (12) after emptying; 2) Open the pneumatic air blowing valve (17) and the pneumatic return water valve (13), and close all the pneumatic feed valve (3), the pneumatic filtrate valve (7), the pneumatic hot water valve (11) and the pneumatic return valve (12); 3) The compressed air generated by the air compressor (16) is dried by the dryer (18). The dried compressed air enters the vertical filter press (1) through the pneumatic air blowing valve (17). The compressed air passes through the filter cloth and finally enters the water return tank (14) through the pneumatic water return valve (13). The compressed air in the water return tank (14) gradually returns to the atmosphere.

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