A filter cloth special for hydrometallurgical leaching purification

Abstract

The present application relates to the technical field of industrial filter cloth, and particularly relates to a special filter cloth for hydrometallurgical leaching purification, which is prepared by heating and melting the mixture of homopolymer polypropylene, copolymer polypropylene, high-density polyethylene and nano titanium oxide and modified antioxidant to prepare mesh wires, and then weaving the mesh wires to prepare the special filter cloth for hydrometallurgical leaching purification. The modified antioxidant is prepared by copolymerization of acrylic ester monomer, 4-allyl catechol, allyl trimethyl ammonium chloride and maleic anhydride. The special filter cloth for hydrometallurgical leaching purification prepared by the present application can slow down the thermal oxidation aging of the filter cloth caused or accelerated by metal ions when the filter cloth is applied to hydrometallurgical leaching purification. The whole preparation process of the present application is simple and easy to operate, has high production efficiency, low cost and is suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of industrial filter cloth technology, and in particular to a filter cloth specifically designed for leaching and purification in hydrometallurgical processes. Background Technology

[0002] Hydrometallurgical leaching purification filter cloth is a special filter cloth designed for hydrometallurgical leaching purification processes. It is typically used in the extraction and purification of metals or metal compounds from raw materials such as ores. To operate normally and maintain its performance, this filter cloth needs to possess properties such as high-temperature resistance, chemical corrosion resistance, and wear resistance, and also needs a long service life. To improve the service life of the filter cloth, antioxidants are often added during its manufacturing process.

[0003] Chinese invention patent CN112206581B discloses an industrial filter cloth specifically for the purification section of a hydrometallurgical process, comprising the following raw materials in parts by weight: 6-8 parts polypropylene, 3-4 parts polyethylene, 30-50 parts anhydrous ethanol, 8-12 parts PET, 10-20 parts component A, 20-30 parts component B, 3-6 parts diphenylsilanediol, 60-70 parts deionized water, and 0.2-0.4 parts antioxidant BHT. Component A possesses good electrical insulation and non-flammability, low thermal shrinkage, and resistance to chemical corrosion. Component B introduces hydrophilic groups, resulting in a filter cloth with good adaptability under high temperature, acidic, or alkaline conditions. However, the presence of a large number of metal ions in the hydrometallurgical process can easily trigger or accelerate the thermo-oxidative aging of the filter cloth. Furthermore, the migration of large amounts of water during filtration leads to the loss of antioxidants from the filter cloth, further accelerating its thermo-oxidative aging. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a special filter cloth for hydrometallurgical leaching purification, in order to solve the problem that when traditional filter cloths are used in hydrometallurgical leaching purification, the presence of a large number of metal ions in the hydrometallurgical process can easily cause or accelerate the thermo-oxidative aging of the filter cloth. Furthermore, during the filtration process, the migration of a large amount of water can lead to the loss of antioxidants in the filter cloth, further accelerating the thermo-oxidative aging of the filter cloth.

[0005] To achieve the above objectives, the present invention provides a special filter cloth for leaching and purification in hydrometallurgical processes, characterized in that it comprises the following raw materials in parts by weight: 30-45 parts of homopolymer polypropylene, 15-21 parts of copolymer polypropylene, 2-8 parts of high-density polyethylene, 1-3 parts of nano-titanium oxide, and 5-15 parts of modified antioxidant.

[0006] The specific synthesis steps of the modified antioxidant are as follows:

[0007] S1: Add acrylate monomers to deionized water, stir for 45-60 min, add initiator, and stir for 2-4 min to obtain aqueous solution A;

[0008] S2: Add 4-allylcatechol, allyltrimethylammonium chloride and maleic anhydride to deionized water and stir for 30-45 min to obtain aqueous solution B;

[0009] S3: Add mercaptopropionic acid and reducing agent to deionized water, then stir for 15-30 minutes to obtain aqueous solution C;

[0010] S4: Heat aqueous solution A to 60-65℃, then simultaneously add aqueous solutions B and C dropwise over a time of 60-90 minutes. After the addition is complete, stir for 2-4 hours, cool to room temperature, and dry to obtain the modified antioxidant.

[0011] The homopolymer polypropylene has a melt flow rate of 2.5-4 g / 10 min at 230°C and 2.16 kg.

[0012] The high-density polyethylene has a melt flow rate of 3-8 g / 10 min at 190°C and 2.16 kg.

[0013] The copolymer polypropylene is an ethylene-propylene copolymer with a vinyl content of 3-4% in molar percentage and a melt flow rate of 5-8 g / 10 min at 230°C and 2.16 kg.

[0014] The average particle size of the nano-titanium oxide is 20-50 nm.

[0015] In step S1, the acrylic monomer is one or a mixture of several of the following: methyl methacrylate, methyl acrylate, ethyl acrylate, methyl isobutyl acrylate, dipropylene succinate, butyl butyl acrylate, and ethylene glycol monoethyl ether acrylate.

[0016] In step S1, the initiator is one or a mixture of several of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0017] In step S1, the mass ratio of acrylate monomers, deionized water, and initiator is 10:10-20:0.5-1.5.

[0018] In step S2, the mass ratio of 4-allylcatechol, allyltrimethylammonium chloride, maleic anhydride, and deionized water is 1-5:3-7:2-4:10-20.

[0019] In step S3, the reducing agent is one or a mixture of several of sodium ascorbate, sodium isoascorbate, and sodium hypophosphite.

[0020] In step S3, the mass ratio of mercaptopropionic acid, reducing agent, and deionized water is 0.1-0.5:0.1-0.3:1-5.

[0021] In step S4, the mass ratio of aqueous solution A, aqueous solution B, and aqueous solution C is 20-30:15-35:1-5.

[0022] Furthermore, the present invention also provides a method for preparing the above-mentioned special filter cloth for hydrometallurgical leaching purification, characterized in that the specific preparation steps are as follows:

[0023] S5: Homopolymer polypropylene, copolymer polypropylene, high-density polyethylene, nano titanium dioxide and modified antioxidant are mixed, heated and melted through a twin-screw extruder, and then the melt is extruded into a spinning box for spinning. The spinning is then cooled and shaped to obtain a mesh.

[0024] S6: The mesh is woven by arranging the warp and weft threads to obtain the filter cloth, which is then subjected to high-temperature setting at 160-190℃, and then calendered at 130-150℃ and 10KPa pressure until the air permeability is 50-100L / m. 2 / s, and finally electrostatic treatment, to obtain a special filter cloth for wet metallurgical leaching purification.

[0025] In step S5, the operating temperature of the twin-screw extruder is 160-180℃.

[0026] In step S5, the working temperature of the spinning box is 160-170℃ and the working pressure is 15-20MPa.

[0027] In step S6, the warp diameter is 0.135-0.23mm, the weft diameter is 600-1500D, the warp density is 30-88 threads / cm, the weft density is 12-23 threads / cm, and the resulting filter cloth for wet metallurgical purification and extraction has an 8-harness twill weave.

[0028] The beneficial effects of this invention are:

[0029] This invention provides a special filter cloth for hydrometallurgical purification and extraction. The filter cloth is prepared by mixing homopolymer polypropylene, copolymer polypropylene, high-density polyethylene and nano-titanium oxide with modified antioxidants, heating and melting them to prepare mesh, and then weaving the mesh with warp and weft threads to obtain a special filter cloth for hydrometallurgical leaching and purification.

[0030] This invention provides a filter cloth specifically for hydrometallurgical purification and extraction. The modified antioxidant is prepared by copolymerizing acrylate monomers, 4-allylcatechol, allyltrimethylammonium chloride, and maleic anhydride. Copolymerizing catechin and quaternary ammonium salt can create a cationic environment near the catechin, which helps to repel metal ions during the filtration process and prevent the influence of metal ions on the antioxidant properties of catechin. This weakens the thermal and oxidative aging of the filter cloth caused or accelerated by metal ions. At the same time, the introduction of maleic anhydride helps to improve the compatibility between the modified antioxidant and the polypropylene matrix, improve the dispersion of the oxidant and reduce the loss of the oxidant during the filtration process, and can effectively extend the service life of the filter cloth.

[0031] This invention provides a special filter cloth for hydrometallurgical purification and extraction. In terms of preparation method, this invention uses a twin-screw extruder to mix, heat and melt the raw materials, and then obtain the mesh by spinning and cooling. The mesh is then prepared by arranging the warp and weft threads and weaving. The whole preparation process is simple and easy to operate, with high production efficiency and low cost, and is suitable for large-scale production. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0033] The properties of the raw materials in the specific embodiments of the present invention are as follows:

[0034] The homopolymer polypropylene has a melt flow rate of 2.8 g / 10 min at 230℃ and 2.16 kg; the copolymer polypropylene is an ethylene-propylene copolymer with a vinyl content of 3.2% and a melt flow rate of 6.3 g / 10 min at 230℃ and 2.16 kg; the high-density polyethylene has a melt flow rate of 4.5 g / 10 min at 190℃ and 2.16 kg; and the average particle size of nano-titanium oxide is 30 nm.

[0035] Example 1

[0036] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0037] S1: Add 10g of methyl methacrylate to 10g of deionized water, stir for 45min, then add 0.5g of ammonium persulfate, and stir for 2min to obtain aqueous solution A;

[0038] S2: Add 1g of 4-allylcatechol, 3g of allyltrimethylammonium chloride and 2g of maleic anhydride to 10g of deionized water and stir for 30min to obtain aqueous solution B;

[0039] S3: Add 0.1g mercaptopropionic acid and 0.1g sodium ascorbate to 1g deionized water, and stir for 15min to obtain aqueous solution C;

[0040] S4: Heat 20g of aqueous solution A to 60℃, then simultaneously add 15g of aqueous solution B and 1g of aqueous solution C. The addition time is controlled at 60min. After the addition is completed, stir for 2h, cool to room temperature, and dry to obtain the modified antioxidant.

[0041] S5: Mix 30g homopolymer polypropylene, 15g copolymer polypropylene, 2g high-density polyethylene, 1g nano titanium dioxide and 5g modified antioxidant, heat and melt them through a twin-screw extruder at a working temperature of 160℃, then extrude the melt into a spinning box for spinning at a working temperature of 160℃ and a working pressure of 15MPa, and cool and shape the spun yarn to obtain the mesh yarn;

[0042] S6: After arranging the warp and weft threads, the mesh is woven with a warp diameter of 0.16mm and a weft diameter of 1000D. The warp density is 50 threads / cm, and the weft density is 18 threads / cm. It is then subjected to high-temperature setting at 160℃, followed by calendering at 130℃ and 10KPa pressure until the air permeability reaches 80L / m². 2 / s, and finally electrostatic treatment, to obtain a special filter cloth for wet metallurgical leaching purification with an 8-hose microstructure.

[0043] Example 2

[0044] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0045] S1: Add 10g of methyl methacrylate to 15g of deionized water, stir for 52min, then add 1g of ammonium persulfate, and stir for 3min to obtain aqueous solution A;

[0046] S2: Add 2.5g of 4-allylcatechol, 5g of allyltrimethylammonium chloride and 3g of maleic anhydride to 15g of deionized water and stir for 37min to obtain aqueous solution B;

[0047] S3: Add 0.3g mercaptopropionic acid and 0.2g sodium ascorbate to 2.5g deionized water, and stir for 15-30 minutes to obtain aqueous solution C;

[0048] S4: Heat 25g of aqueous solution A to 62℃, then simultaneously add 27.5g of aqueous solution B and 2.5g of aqueous solution C dropwise over a time of 75min. After the addition is complete, stir for 3h, cool to room temperature, and dry to obtain the modified antioxidant.

[0049] S5: Mix 35g homopolymer polypropylene, 18g copolymer polypropylene, 5g high-density polyethylene, 2g nano titanium dioxide and 10g modified antioxidant, heat and melt them through a twin-screw extruder at a working temperature of 170℃, then extrude the melt into a spinning box for spinning at a working temperature of 165℃ and a working pressure of 17MPa, and cool and shape the spun yarn to obtain the mesh yarn;

[0050] S6: After arranging the warp and weft threads, the mesh is woven with a warp diameter of 0.16mm and a weft diameter of 1000D. The warp density is 50 threads / cm, and the weft density is 18 threads / cm. It is then subjected to high-temperature setting at 175℃, followed by calendering at 140℃ and 10KPa pressure until the air permeability reaches 80L / m². 2 / s, and finally electrostatic treatment, to obtain a special filter cloth for wet metallurgical leaching purification with an 8-hose microstructure.

[0051] Example 3

[0052] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0053] S1: Add 10g of methyl methacrylate to 20g of deionized water, stir for 60min, then add 1.5g of ammonium persulfate, and stir for 4min to obtain aqueous solution A;

[0054] S2: Add 5g of 4-allylcatechol, 7g of allyltrimethylammonium chloride and 4g of maleic anhydride to 20g of deionized water and stir for 45min to obtain aqueous solution B;

[0055] S3: Add 0.5g mercaptopropionic acid and 0.3g sodium ascorbate to 5g deionized water, and stir for 30min to obtain aqueous solution C;

[0056] S4: Heat 30g of aqueous solution A to 65℃, then simultaneously add 35g of aqueous solution B and 5g of aqueous solution C. The addition time is controlled at 90min. After the addition is completed, stir for 4h, cool to room temperature, and dry to obtain the modified antioxidant.

[0057] S5: Mix 45g homopolymer polypropylene, 21g copolymer polypropylene, 8g high-density polyethylene, 3g nano titanium dioxide and 15g modified antioxidant, heat and melt them through a twin-screw extruder at a working temperature of 180℃, then extrude the melt into a spinning box for spinning at a working temperature of 170℃ and a working pressure of 20MPa, and cool and shape the spun yarn to obtain the mesh yarn;

[0058] S6: After arranging the warp and weft threads, the mesh is woven with a warp diameter of 0.16mm and a weft diameter of 1000D. The warp density is 50 threads / cm, and the weft density is 18 threads / cm. It is then subjected to high-temperature setting at 190℃, and subsequently calendered at 150℃ and 10KPa pressure until the air permeability reaches 80L / m². 2 / s, and finally electrostatic treatment, to obtain a special filter cloth for wet metallurgical leaching purification with an 8-hose microstructure.

[0059] Example 4

[0060] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0061] S1: Add 5g of methyl methacrylate and 5g of ethyl acrylate to 15g of deionized water, stir for 52min, then add 1g of potassium persulfate, and stir for 3min to obtain aqueous solution A;

[0062] S2: Add 1g of 4-allylcatechol, 7g of allyltrimethylammonium chloride and 3g of maleic anhydride to 15g of deionized water and stir for 37min to obtain aqueous solution B;

[0063] S3: Add 0.3g mercaptopropionic acid and 0.2g sodium hypophosphite to 2.5g deionized water, and then stir for 15-30 minutes to obtain aqueous solution C;

[0064] S4: Same as Example 2; S5: Same as Example 2; S6: Same as Example 2.

[0065] Example 5

[0066] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0067] S1: Same as Example 2;

[0068] S2: Add 5g of 4-allylcatechol, 3g of allyltrimethylammonium chloride and 3g of maleic anhydride to 15g of deionized water and stir for 37min to obtain aqueous solution B;

[0069] S3: Same as Example 2; S4: Same as Example 2; S5: Same as Example 2; S6: Same as Example 2.

[0070] Comparative Example 1

[0071] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0072] S1: Same as Example 2;

[0073] S2: Add 5g allyltrimethylammonium chloride and 3g maleic anhydride to 15g deionized water and stir for 37min to obtain aqueous solution B;

[0074] S3: Same as Example 2; S4: Same as Example 2; S5: Same as Example 2; S6: Same as Example 2.

[0075] Comparative Example 2

[0076] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0077] S1: Same as Example 2;

[0078] S2: Add 2.5g of 4-allylcatechol and 3g of maleic anhydride to 15g of deionized water and stir for 37min to obtain aqueous solution B;

[0079] S3: Same as Example 2; S4: Same as Example 2; S5: Same as Example 2; S6: Same as Example 2.

[0080] Comparative Example 3

[0081] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0082] S1: Same as Example 2;

[0083] S2: Add 3g of maleic anhydride to 15g of deionized water and stir for 37min to obtain aqueous solution B;

[0084] S3: Same as Example 2; S4: Same as Example 2; S5: Same as Example 2; S6: Same as Example 2.

[0085] Comparative Example 4

[0086] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0087] S1: Same as Example 2;

[0088] S2: Add 2.5g of 4-allylcatechol and 5g of allyltrimethylammonium chloride to 15g of deionized water and stir for 37min to obtain aqueous solution B;

[0089] S3: Same as Example 2; S4: Same as Example 2; S5: Same as Example 2; S6: Same as Example 2.

[0090] Comparative Example 5

[0091] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0092] S1: Same as Example 2; S2: Same as Example 2;

[0093] S3: Heat 25g of aqueous solution A to 62℃, then add 27.5g of aqueous solution B dropwise over a time of 75min. After the addition is complete, stir for 3h, cool to room temperature, and dry to obtain the modified antioxidant.

[0094] S4: Mix 35g homopolymer polypropylene, 18g copolymer polypropylene, 5g high-density polyethylene, 2g nano titanium dioxide and 10g modified antioxidant, heat and melt them through a twin-screw extruder at a working temperature of 170℃, then extrude the melt into a spinning box for spinning at a working temperature of 165℃ and a working pressure of 17MPa, and cool and shape the spun yarn to obtain the mesh yarn;

[0095] S5: After arranging the warp and weft threads, the mesh is woven with a warp diameter of 0.16mm and a weft diameter of 1000D. The warp density is 50 threads / cm, and the weft density is 18 threads / cm. It is then subjected to high-temperature setting at 175℃, followed by calendering at 140℃ and 10KPa pressure until the air permeability reaches 80L / m². 2 / s, and finally electrostatic treatment, to obtain a special filter cloth for wet metallurgical leaching purification with an 8-hose microstructure.

[0096] Comparative Example 6

[0097] A method for preparing a filter cloth specifically for leaching and purification in hydrometallurgical processes includes the following steps:

[0098] S1: Mix 35g homopolymer polypropylene, 18g copolymer polypropylene, 5g high-density polyethylene, 2g nano titanium dioxide, 1.2g 4-allyl catechol and 2.5g allyltrimethylammonium chloride, heat and melt them through a twin-screw extruder at a working temperature of 170℃, then extrude the melt into a spinning box for spinning at a working temperature of 165℃ and a working pressure of 17MPa. Cool and set the spun yarn to obtain a mesh.

[0099] S2: After arranging the warp and weft threads, the mesh is woven with a warp diameter of 0.16mm and a weft diameter of 1000D. The warp density is 50 threads / cm, and the weft density is 18 threads / cm. It is then subjected to high-temperature setting at 175℃, and subsequently calendered at 140℃ and 10KPa pressure until the air permeability reaches 80L / m². 2 / s, and finally electrostatic treatment, to obtain a special filter cloth for wet metallurgical leaching purification with an 8-hose microstructure.

[0100] Performance testing

[0101] Tensile strength test: The performance of the special filter cloths for wet metallurgical leaching purification prepared in Examples 1-5 and Comparative Examples 1-6 was tested. The initial tensile strength was first tested at 25°C, and then the tensile strength was tested every 5°C. When the tensile strength retention rate of the filter cloth was less than 90%, the temperature and the tensile strength retention rate at that temperature were recorded. The test results are shown in Table 1 below.

[0102] Anti-aging test: The special filter cloths for wet metallurgical leaching and purification prepared in Examples 1-5 and Comparative Examples 1-6 were placed in an aqueous solution with a copper sulfate concentration of 10wt% and a pressure difference of 100Pa on both sides. After soaking at 80℃ for 30 days and 60 days, the tensile strength of the filter cloth was measured. The results are shown in Table 1.

[0103] Water permeability test: The special filter cloths for wet metallurgical leaching and purification prepared in Examples 1-5 and Comparative Examples 1-6 were placed in an aqueous solution with a pressure difference of 100 Pa on both sides. The water permeability per unit area of ​​the filter cloth was tested. The test results are shown in Table 1 below.

[0104] Table 1. Performance test results of Examples 1-5 and Comparative Examples 1-6

[0105]

[0106]

[0107] Data Analysis

[0108] As can be seen from Examples 1-5, the modified antioxidant prepared by the present invention can slow down or accelerate the thermo-oxidative aging of the filter cloth initiated by metal ions, thereby extending the service life of the filter cloth. As can be seen from Examples 2 and Comparative Examples 1-3, the 4-allylcatechol and allyltrimethylammonium chloride of the present invention synergistically improve the thermo-oxidative aging resistance of the filter cloth. As can be seen from Examples 2 and Comparative Example 4, the introduction of maleic anhydride plays a crucial role in the tensile strength and thermo-oxidative aging resistance of the filter cloth. The effect on thermo-oxidative aging may be due to the introduction of maleic anhydride increasing the binding force between the antioxidant and polypropylene, thereby slowing down the loss of antioxidant in the filtrate.

[0109] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0110] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A filter cloth specifically for leaching and purification in hydrometallurgical processes, characterized in that, The raw materials include the following parts by weight: 30-45 parts homopolymer polypropylene, 15-21 parts copolymer polypropylene, 2-8 parts high-density polyethylene, 1-3 parts nano titanium dioxide, and 5-15 parts modified antioxidant. The specific synthesis steps of the modified antioxidant are as follows: S1: Add acrylate monomers to deionized water, stir for 45-60 min, add initiator, and stir for 2-4 min to obtain aqueous solution A; S2: Add 4-allylcatechol, allyltrimethylammonium chloride and maleic anhydride to deionized water and stir for 30-45 min to obtain aqueous solution B; S3: Add mercaptopropionic acid and reducing agent to deionized water, then stir for 15-30 minutes to obtain aqueous solution C; S4: Heat aqueous solution A to 60-65℃, then simultaneously add aqueous solutions B and C dropwise over a time of 60-90 minutes. After the addition is complete, stir for 2-4 hours, cool to room temperature, and dry to obtain the modified antioxidant.

2. The filter cloth for leaching and purification in hydrometallurgical processes according to claim 1, characterized in that, The homopolymer polypropylene has a melt flow rate of 2.5-4 g / 10 min at 230°C and 2.16 kg; the high-density polyethylene has a melt flow rate of 3-8 g / 10 min at 190°C and 2.16 kg.

3. The filter cloth for leaching and purification in hydrometallurgical processes according to claim 1, characterized in that, The copolymer polypropylene is an ethylene-propylene copolymer with a vinyl content of 3-4% in molar percentage and a melt flow rate of 5-8 g / 10 min at 230°C and 2.16 kg.

4. The filter cloth for leaching and purification in hydrometallurgical processes according to claim 1, characterized in that, The average particle size of the nano-titanium oxide is 20-50 nm.

5. The filter cloth for leaching and purification in hydrometallurgical processes according to claim 1, characterized in that, In step S1, the acrylic monomer is one or a mixture of several of the following: methyl methacrylate, methyl acrylate, ethyl acrylate, methyl isobutylene oxide, dipropylene succinate, butyl butyl acrylate, and ethylene glycol monoethyl ether acrylate; in step S1, the initiator is one or a mixture of several of the following: ammonium persulfate, potassium persulfate, and sodium persulfate; in step S3, the reducing agent is one or a mixture of several of the following: sodium ascorbate, sodium isoascorbate, and sodium hypophosphite.

6. The filter cloth for leaching and purification in hydrometallurgical processes according to claim 1, characterized in that, In step S1, the mass ratio of acrylate monomers, deionized water, and initiator is 10:10-20:0.5-1.5; in step S2, the mass ratio of 4-allylcatechol, allyltrimethylammonium chloride, maleic anhydride, and deionized water is 1-5:3-7:2-4:10-20; and in step S3, the mass ratio of mercaptopropionic acid, reducing agent, and deionized water is 0.1-0.5:0.1-0.3:1-5.

7. The filter cloth for leaching and purification in hydrometallurgical processes according to claim 1, characterized in that, In step S4, the mass ratio of aqueous solution A, aqueous solution B, and aqueous solution C is 20-30:15-35:1-5.

8. A method for preparing a special filter cloth for hydrometallurgical leaching purification according to any one of claims 1-7, characterized in that, The specific preparation steps are as follows: S5: Homopolymer polypropylene, copolymer polypropylene, high-density polyethylene, nano titanium dioxide and modified antioxidant are mixed, heated and melted through a twin-screw extruder, and then the melt is extruded into a spinning box for spinning. The spinning is then cooled and shaped to obtain a mesh. S6: The mesh is woven by arranging the warp and weft threads to obtain the filter cloth, which is then subjected to high-temperature setting at 160-190℃, and then calendered at 130-150℃ and 10KPa pressure until the air permeability is 50-100L / m. 2 / s, and finally electrostatic treatment, to obtain a special filter cloth for wet metallurgical leaching purification.

9. The method for preparing the special filter cloth for hydrometallurgical leaching purification according to claim 8, characterized in that, The operating temperature of the twin-screw extruder in step S5 is 230-275℃; the operating temperature of the spinning box in step S5 is 160-170℃, and the operating pressure is 15-20MPa.

10. The method for preparing the special filter cloth for hydrometallurgical leaching purification according to claim 8, characterized in that, In step S6, the warp diameter is 0.135-0.23mm, the weft diameter is 600-1500D, the warp density is 30-88 threads / cm, and the weft density is 12-23 threads / cm. The resulting filter cloth for wet metallurgical purification and extraction has an 8-harness twill weave.

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