A polyacrylamide flocculant for nickel ore amphoteric cross-linking type and a preparation method thereof

Abstract

This invention relates to a polyacrylamide flocculant for amphoteric crosslinking of nickel ore and its preparation method. The raw materials for preparing the polyacrylamide flocculant include, by parts: 160-210 parts acrylamide crystals, 5-45 parts anionic monomers, 1-9 parts fluorinated cationic hydrophobic monomers, 0.3-2.5 parts castor oil polyoxyethylene ether borate, 5-35 parts cationic monomers, 0.5-2.5 parts temperature- and salt-resistant monomers, 0.2-2 parts crosslinking agent, 0.6-2.2 parts sodium perfluorononenoxybenzenesulfonate, 1-3 parts solvent promoter, 5-10 parts 48% liquid alkali, 550-750 parts water, 0.02-1.9 parts chain transfer agent, and 0.002-0.7 parts mixed initiator. The polyacrylamide flocculant provided by this invention is suitable for efficient flocculation treatment of nickel ore slurry, and has the characteristics of good flocculation effect, strong temperature and salt resistance, and adaptability to complex slurry environments, which can significantly improve the separation efficiency of nickel ore.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and in particular to a polyacrylamide flocculant for amphoteric crosslinking of nickel ore and its preparation method. Background Technology

[0002] Nickel, as an important strategic metal, is widely used in stainless steel manufacturing, battery materials, aerospace, and other fields, and its demand continues to grow with industrial development. The efficient development and utilization of nickel ore resources is key to ensuring the sustainable development of the nickel industry, and the solid-liquid separation efficiency of the ore slurry during the beneficiation process directly affects the nickel ore beneficiation index and subsequent smelting costs.

[0003] In nickel ore beneficiation processes, the slurry typically contains a large amount of fine-grained minerals, clay impurities, and electrolytes (such as Na). + Ca 2+ Mg 2+ (etc.), and often accompanied by high temperatures and pH fluctuations, traditional flocculants are difficult to adapt to such complex environments. Currently, the flocculants commonly used in industry are mainly single-ionic polyacrylamide: anionic polyacrylamide relies on molecular chain bridging, but its adsorption capacity for positively charged mineral particles is weak, and in high-salt environments, it is prone to charge shielding, leading to a decrease in flocculation effect; cationic polyacrylamide can adsorb negatively charged particles through electrostatic neutralization, but in acidic mineral slurries, the amino groups are easily protonated, the molecular chains coil up, and the bridging ability is limited.

[0004] Therefore, developing an amphoteric crosslinked polyacrylamide flocculant that combines high-efficiency flocculation, excellent temperature and salt resistance, and adaptability to the complex slurry environment of nickel ore is of great significance for improving nickel ore sorting efficiency and reducing production costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing flocculants for nickel ore slurry have poor flocculation effect and poor solid-liquid separation effect.

[0006] To address the aforementioned technical problems, this invention provides a polyacrylamide flocculant for amphoteric crosslinking of nickel ore. The raw materials for preparing the polyacrylamide flocculant, by parts, include: 160-210 parts acrylamide crystals, 5-45 parts anionic monomer, 1-9 parts fluorinated cationic hydrophobic monomer, 0.3-2.5 parts castor oil polyoxyethylene ether borate, 5-35 parts cationic monomer, 0.5-2.5 parts temperature- and salt-resistant monomer, 0.2-2 parts crosslinking agent, 0.6-2.2 parts sodium perfluorononenoxybenzenesulfonate, 1-3 parts solvent promoter, 5-10 parts 48% liquid alkali, 550-750 parts water, 0.02-1.9 parts chain transfer agent, and 0.002-0.7 parts mixed initiator.

[0007] The acrylamide crystals described in this invention are 160 to 210 parts, for example, 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, or 210 parts.

[0008] The anionic monomer of the present invention is 5 to 45 parts, for example, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or 45 parts, etc.

[0009] Preferably, the anionic monomer comprises any one or a combination of at least two of sodium acrylate, acrylic acid, itaconic acid, or methacrylic acid.

[0010] In this invention, the introduction of anionic monomers can introduce negatively charged groups such as carboxyl groups into the polyacrylamide molecular chain, thereby enhancing the flocculant's adsorption capacity for positively charged nickel ore particles and metal ions in the nickel ore system, while also improving the water solubility of the flocculant and promoting the formation and sedimentation of flocs.

[0011] The fluorinated cationic hydrophobic monomer of the present invention is 1 to 9 parts, for example, 1 part, 3 parts, 5 parts, 7 parts or 9 parts, etc.

[0012] Preferably, the fluorinated cationic hydrophobic monomer includes any one or a combination of at least two of dodecylfluoroheptyl methacrylate, hexafluorobutyl acrylate, or dodecylfluoroheptyl methacrylate.

[0013] The fluorine-containing cationic hydrophobic monomer described in this invention combines the characteristics of cationic charge and the hydrophobic properties of fluorine, which can enhance the aggregation ability of flocculant molecular chains, improve floc strength and sedimentation speed, and at the same time, the introduction of fluorine can significantly improve the temperature resistance, salt resistance and acid and alkali resistance of flocculants.

[0014] The castor oil polyoxyethylene ether borate ester of the present invention is 0.3 to 2.5 parts, for example, 0.3 parts, 1 part, 1.5 parts or 2.5 parts, etc.

[0015] In this invention, castor oil polyoxyethylene ether borate, as an additive with both surface activity and cross-linking assist functions, can optimize floc structure and strength, improve the temperature resistance of flocculants, and simultaneously improve raw material compatibility and polymerization uniformity. Castor oil polyoxyethylene ether borate possesses certain surface activity, which can promote the dispersion of poorly soluble monomers such as fluorinated cationic hydrophobic monomers in aqueous solutions, prevent monomer aggregation, ensure uniform polymerization, reduce molecular weight fluctuations in the polymerization products, and improve the stability of flocculant product quality.

[0016] The cationic monomer of the present invention is 5 to 35 parts, for example, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts or 35 parts, etc.

[0017] Preferably, the cationic monomer includes any one or a combination of at least two of dimethyldiallyl ammonium chloride, diallyl dimethyl ammonium bromide, and (meth)acryloyloxyethyl trimethyl ammonium chloride, and more preferably diallyl dimethyl ammonium bromide and methacryloyloxyethyl trimethyl ammonium chloride.

[0018] In this invention, the introduction of cationic monomers can adjust the cationicity of the flocculant and work synergistically with anionic monomers to achieve comprehensive capture of particles with different charge properties in the nickel ore system.

[0019] The temperature- and salt-resistant monomer is 0.5 to 2.5 parts, for example, it can be 0.5 parts, 1 part, 2 parts or 2.5 parts, etc.

[0020] Preferably, the temperature- and salt-resistant monomer is N-vinylformamide and / or vinylbenzenesulfonic acid.

[0021] The crosslinking agent described in this invention is 0.2 to 2 parts, for example, 0.2 parts, 0.7 parts, 1 part, 1.5 parts, or 2 parts, etc.

[0022] Preferably, the crosslinking agent is at least two of 1,4-butanediol diacrylate, ethylene glycol dimethacrylate, or hexamethylene diisocyanate.

[0023] The sodium perfluorononenoxybenzenesulfonate of the present invention is 0.6 to 2.2 parts, for example, 0.6 parts, 1 part, 2 parts, 2.2 parts, etc.

[0024] In this invention, sodium perfluorononenoxybenzenesulfonate can form a strong hydrophobic association with the fluorinated hydrophobic groups of fluorinated cationic hydrophobic monomers, constructing a stable hydrophobic association network, significantly enhancing the aggregation ability of polyacrylamide molecular chains. At the same time, it works synergistically with anionic and cationic monomers to achieve comprehensive capture of particles with different charge properties, further improving flocculation efficiency.

[0025] The solvent used in this invention is 1 to 3 parts, for example, 1 part, 2 parts, 3 parts, etc.

[0026] Preferably, the co-solvent comprises any one or a combination of at least two of hexamethylphosphoramide, urea, and sodium dodecylbenzenesulfonate, and more preferably a combination of hexamethylphosphoramide and urea.

[0027] The 48% liquid alkali described in this invention can be 5 to 10 parts, for example, 5 parts, 7 parts, 8 parts, or 10 parts. 48% liquid alkali refers to a sodium hydroxide aqueous solution with a mass concentration of 48%.

[0028] The water mentioned in this invention is 550 to 750 parts, for example, 550 parts, 600 parts, 650 parts, 700 parts or 750 parts, etc.

[0029] The chain transfer agent described in this invention is used in quantities of 0.02 to 1.9 parts, for example, 0.02 parts, 1 part, 1.5 parts, or 1.9 parts.

[0030] Preferably, the chain transfer agent comprises any one or a combination of at least two of sodium formate, isopropanol, sodium hypophosphite, and sodium methacrylate sulfonate, with sodium hypophosphite being the most preferred.

[0031] The mixed initiator described in this invention is 0.002 to 0.7 parts, for example, it can be 0.002 parts, 0.01 parts, 0.1 parts, 0.5 parts, 0.7 parts, etc.

[0032] Preferably, the mixed initiator is a combination of an azo initiator and a redox initiator; The azo initiator includes any one or a combination of at least two of azobisisobutyramidine dihydrochloride, azobisisoheptanenitrile, azobisisobutyronitrile, and 4,4'-azobis(4-cyanopentanoic acid), preferably azobisisobutyronitrile; The redox initiator includes any one or a combination of at least two of benzoyl peroxide, ammonium persulfate, potassium persulfate, sodium bisulfite, formaldehyde, ferrous sulfate, or sodium bisulfite, preferably potassium persulfate and sodium bisulfite.

[0033] In a second aspect, the present invention provides a method for preparing the amphoteric crosslinking polyacrylamide flocculant for nickel ore as described in the first aspect, the preparation method comprising the following steps: (1) Acrylamide crystals, anionic monomers, fluorinated cationic hydrophobic monomers, castor oil polyoxyethylene ether borate, cationic monomers, temperature-resistant and salt-resistant monomers, crosslinking agents, sodium perfluorononenoxybenzenesulfonate, co-solvents, 48% liquid alkali, and water are mixed and the pH value is adjusted to obtain a mixed solution. (2) Add chain transfer agent and mixed initiator to the mixed solution obtained in step (1) to carry out copolymerization reaction. After the copolymerization reaction is completed, granulate, dry and sieve the product to obtain the branched polyacrylamide flocculant.

[0034] In step (1) of this invention, the system can be ultrasonically treated for 20 minutes under stirring at 250-300 rpm to form a homogeneous and transparent solution; at the same time, acrylic acid is used to adjust the pH value to 6.5-7.5 and the temperature to 0-2℃.

[0035] The copolymerization reaction in step (2): First, high-purity nitrogen gas is introduced into the mixture for 45 minutes; after adding the chain transfer agent and mixed initiator, polymerization is initiated, and the reaction ends when the temperature no longer rises after 6 hours; Granulation: The polymer block obtained from the copolymerization reaction is put into a granulator for granulation, with a particle size of 2-6 mm. Drying: The granules are transferred to a drying oven and dried at 60-80℃ for 2-4 hours, controlling the moisture content of the finished product to ≤8%; Grinding and sieving: The dried granules are ground by a pulverizer and then passed through an 80-mesh standard sieve. The sieve-underfill material is collected, which is a type of amphoteric crosslinking polyacrylamide flocculant for nickel ore; Implementing this invention has the following beneficial effects: This invention employs an amphoteric design, simultaneously introducing anionic and cationic monomers. Through copolymerization of the amphoteric monomers and the introduction of cross-linking structures, combined with performance optimization using temperature- and salt-resistant monomers, it can simultaneously achieve all-round particle adsorption. Compared with single ionic flocculants, it has a wider flocculation range and higher capture efficiency. At the same time, the introduction of castor oil polyoxyethylene ether borate further optimizes the floc structure, making the flocs denser and stronger, preventing floc breakage during stirring and transportation, and ensuring stable solid-liquid separation effect.

[0036] This invention is applicable to the efficient flocculation treatment of nickel ore slurry, and features good flocculation effect, strong temperature and salt resistance, and adaptability to complex slurry environments, which can significantly improve the separation efficiency of nickel ore. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1 This embodiment provides a polyacrylamide flocculant for amphoteric crosslinking of nickel ore. Acrylamide crystals 185 parts by weight, sodium acrylate 10 parts by weight, itaconic acid 12 parts by weight, dodecafluoroheptyl methacrylate 2.3 parts by weight, castor oil polyoxyethylene ether borate 0.6 parts by weight, diallyl dimethyl ammonium bromide 15 parts by weight, methacryloyloxyethyl trimethyl ammonium chloride 7 parts by weight, N-vinylformamide 0.9 parts by weight, 1,4-butanediol diacrylate 0.2 parts by weight, hexamethylene diisocyanate 0.6 parts by weight, sodium perfluorononenoxybenzenesulfonate 1.2 parts by weight, hexamethylphosphoramide 0.3 parts by weight, urea 2 parts by weight, 48% liquid alkali 5 parts by weight, water 620 parts by weight, sodium hypophosphite 0.05 parts by weight, azobisisobutyronitrile 0.3 parts by weight, potassium persulfate 0.003 parts by weight, sodium bisulfite 0.0025 parts by weight.

[0039] Preparation method: (1) Acrylamide crystals, sodium acrylate, itaconic acid, dodecafluoroheptyl methacrylate, castor oil polyoxyethylene ether borate, diallyl dimethyl ammonium bromide, methacryloyloxyethyl trimethyl ammonium chloride, N-vinylformamide, 1,4-butanediol diacrylate, hexamethylene diisocyanate, sodium perfluorononenoxybenzenesulfonate, hexamethylphosphoramide, urea, 48% liquid alkali, and water were stirred at 280 rpm and ultrasonically treated for 20 min. The mixture was then adjusted to pH 7 and the temperature was set to 2℃ to obtain a homogeneous and transparent solution. (2) Add sodium hypophosphite, azobisisobutyronitrile, potassium persulfate and sodium bisulfite to the mixed solution obtained in step (1) to carry out copolymerization reaction. After the copolymerization reaction is completed, granulate the product with a particle size of 5 mm, dry it at 70°C for 3 h, and then sieve it through 80 mesh to obtain the polyacrylamide flocculant for nickel ore amphoteric crosslinking.

[0040] Example 2 This embodiment provides a polyacrylamide flocculant for amphoteric crosslinking of nickel ore. Acrylamide crystals 195 parts by weight, acrylic acid 10 parts by weight, itaconic acid 12 parts by weight, dodecafluoroheptyl methacrylate 2.3 parts by weight, castor oil polyoxyethylene ether borate 0.6 parts by weight, dimethyl diallyl ammonium chloride 13 parts by weight, methacryloyloxyethyl trimethyl ammonium chloride 10 parts by weight, N-vinylformamide 0.9 parts by weight, 1,4-butanediol diacrylate 0.4 parts by weight, hexamethylene diisocyanate 0.6 parts by weight, sodium perfluorononenoxybenzenesulfonate 1.2 parts by weight, hexamethylphosphoramide 0.4 parts by weight, urea 2 parts by weight, 48% liquid alkali 5 parts by weight, deionized water 650 parts by weight, sodium hypophosphite 0.09 parts by weight, azobisisobutyronitrile 0.35 parts by weight, potassium persulfate 0.003 parts by weight, sodium bisulfite 0.0025 parts by weight.

[0041] Example 3 This embodiment provides a polyacrylamide flocculant for amphoteric crosslinking of nickel ore. Acrylamide crystals 185 parts by weight, sodium acrylate 10 parts by weight, itaconic acid 12 parts by weight, dodecafluoroheptyl methacrylate 2.3 parts by weight, castor oil polyoxyethylene ether borate 0.6 parts by weight, diallyl dimethyl ammonium bromide 10 parts by weight, methacryloyloxyethyl trimethyl ammonium chloride 14 parts by weight, vinylbenzenesulfonic acid 1.5 parts by weight, ethylene glycol dimethacrylate 0.1 parts by weight, hexamethylene diisocyanate 0.4 parts by weight, sodium perfluorononenoxybenzenesulfonate 1.2 parts by weight, hexamethylphosphoramide 0.3 parts by weight, urea 2 parts by weight, 48% liquid alkali 5 parts by weight, deionized water 620 parts by weight, sodium hypophosphite 0.05 parts by weight, azobisisobutyronitrile 0.3 parts by weight, potassium persulfate 0.003 parts by weight, sodium bisulfite 0.0025 parts by weight.

[0042] Comparative Example 1 The difference between this comparative example and Example 1 is that no crosslinking agent is added.

[0043] Comparative Example 2 The difference between this comparative example and Example 1 is that sodium perfluorononenoxybenzenesulfonate, hexamethylphosphoramide, and urea are not added.

[0044] Comparative Example 3 The difference between this comparative example and Example 1 is that dodecafluoroheptyl methacrylate and castor oil polyoxyethylene ether borate are not added.

[0045] Comparative Example 4 The difference between this comparative example and Example 1 is that no cationic monomer is added to this comparative example.

[0046] Comparative Example 5 The difference between this comparative example and Example 1 is that no anionic monomer is added to this comparative example.

[0047] Comparative Example 6 The difference between this comparative example and Example 1 is that castor oil polyoxyethylene ether borate is replaced with polyoxyethylene sorbitan monooleate.

[0048] Comparative Example 7 The difference between this comparative example and Example 1 is that sodium perfluorononenoxybenzenesulfonate is replaced with sodium dodecylbenzenesulfonate.

[0049] Performance testing: 1. Relative molecular mass, cationicity, and water-insoluble matter The relative molecular mass M, cationicity (%), and water-insoluble matter (%) were tested according to the test methods in the national standard GB / T 31246-2025.

[0050] 2. Settling time, supernatant turbidity, and floc characteristics A) Preparation of flocculant mother liquor Weigh (1.000±0.001) g of polyacrylamide (PAM) powder and slowly add it to a beaker containing approximately 500 mL of pure water. Simultaneously, stir continuously at 200–400 r / min to ensure uniform dispersion of the powder (avoid clumping). After the powder is completely wetted and dispersed, continue stirring for at least 1 hour until fully dissolved. After cooling, transfer the solution to a 500 mL volumetric flask and dilute to the mark with pure water to obtain a 0.1% (w / v) PAM stock solution. This stock solution should be prepared and used immediately; it should not be stored at room temperature for more than 2 hours.

[0051] B) Simulated nickel ore slurry. The solid components of the simulated nickel ore slurry are mainly Fe2O3, CaSO4, and NiAl(CO3)(OH)3. The ionic components in the solution are mainly Ni. 2+ Co 2+ Fe 3+ Si 4+ SO4 2- The density of the liquid portion is 1.08~1.09 g / cm³. 3 The solid particle size distribution is D80 = 5~8μm.

[0052] C) Test Procedure Standard beaker sedimentation test This experiment was conducted to determine the settling properties of flocculants.

[0053] Sampling: Take 500 mL of uniform simulated nickel ore slurry and pour it into six 500 mL stoppered graduated cylinders.

[0054] Add flocculant: Use a pipette or micropipette to add 1 ml of 0.1% PAM stock solution to each graduated cylinder.

[0055] Mixing and flocculation: Tighten the stopper of the measuring cylinder and invert it 10 times with uniform force and frequency (completed within about 30 seconds) to ensure that the flocculant is fully mixed with the simulated nickel ore slurry.

[0056] Settling: Place the graduated cylinder vertically on the experimental table and start the stopwatch at the same time.

[0057] Observation and Recording: Settling time: The time (t, unit: seconds) required for the interface between the clear liquid and flocculent to drop from the 500 mL mark to the 300 mL mark (i.e., settling 200 mL).

[0058] Turbidity of the supernatant: After standing for 5 minutes, carefully aspirate about 50 mL of the supernatant from the top of the graduated cylinder using the siphon method, and measure its turbidity (NTU) using a turbidimeter.

[0059] Floc characteristics observation: Qualitatively record the size, density, and interface clarity of the flocs. The obtained performance data are shown in Table 1 below: Table 1 The experimental data above show that the amphoteric crosslinked polyacrylamide flocculant prepared by this invention has a moderate molecular weight and low water-insoluble content, exhibiting both excellent flocculation and sedimentation performance and clarification effect. Compared with the comparative examples, this invention, through amphoteric copolymerization of anionic and cationic monomers and a complex crosslinked structure, combined with the synergistic effect of fluorinated cationic hydrophobic monomers, castor oil polyoxyethylene ether borate, and sodium perfluorononenoxybenzenesulfonate, significantly shortens the slurry settling time, reduces the turbidity of the supernatant, and produces coarser and denser flocs with a clearer solid-liquid interface.

[0060] The absence of any functional component, such as crosslinking agent, cationic monomer, or anionic monomer, or the replacement of key functional additives, significantly degrades the molecular weight, floc strength, temperature and salt resistance, and slurry clarification performance of the flocculant. This demonstrates that there is a significant synergistic effect among the raw material components of this invention. It is suitable for high-salt, fine-particle, and complex slurry environments of nickel ore, exhibits excellent flocculation and separation effects, and has good application value and promotion prospects.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polyacrylamide flocculant for amphoteric crosslinking of nickel ore, characterized in that, The raw materials for preparing the polyacrylamide flocculant include, by parts: 160-210 parts acrylamide crystals, 5-45 parts anionic monomers, 1-9 parts fluorinated cationic hydrophobic monomers, 0.3-2.5 parts castor oil polyoxyethylene ether borate, 5-35 parts cationic monomers, 0.5-2.5 parts temperature- and salt-resistant monomers, 0.2-2 parts crosslinking agent, 0.6-2.2 parts sodium perfluorononenoxybenzenesulfonate, 1-3 parts solvent promoter, 5-10 parts 48% liquid alkali, 550-750 parts water, 0.02-1.9 parts chain transfer agent, and 0.002-0.7 parts mixed initiator.

2. The polyacrylamide flocculant according to claim 1, characterized in that, The anionic monomer includes any one or a combination of at least two of sodium acrylate, acrylic acid, itaconic acid, or methacrylic acid.

3. The polyacrylamide flocculant according to claim 1, characterized in that, The fluorinated cationic hydrophobic monomer includes any one or a combination of at least two of dodecylfluoroheptyl methacrylate, hexafluorobutyl acrylate, or dodecylfluoroheptyl methacrylate.

4. The polyacrylamide flocculant according to claim 1, characterized in that, The cationic monomer includes any one or a combination of at least two of dimethyl diallyl ammonium chloride, diallyl dimethyl ammonium bromide, and (meth)acryloyloxyethyl trimethyl ammonium chloride, preferably diallyl dimethyl ammonium bromide and methacryloyloxyethyl trimethyl ammonium chloride.

5. The polyacrylamide flocculant according to claim 1, characterized in that, The temperature- and salt-resistant monomer is N-vinylformamide and / or vinylbenzenesulfonic acid.

6. The polyacrylamide flocculant according to claim 1, characterized in that, The crosslinking agent is at least two of 1,4-butanediol diacrylate, ethylene glycol dimethacrylate, or hexamethylene diisocyanate.

7. The polyacrylamide flocculant according to claim 1, characterized in that, The co-solvent includes any one or a combination of at least two of hexamethylphosphoramide, urea, and sodium dodecylbenzenesulfonate, preferably a combination of hexamethylphosphoramide and urea.

8. The polyacrylamide flocculant according to claim 1, characterized in that, The chain transfer agent includes any one or a combination of at least two of sodium formate, isopropanol, sodium hypophosphite, and sodium methyl methacrylate, preferably sodium hypophosphite.

9. The polyacrylamide flocculant according to claim 1, characterized in that, The mixed initiator is a combination of an azo initiator and a redox initiator; The azo initiator includes any one or a combination of at least two of azobisisobutyramidine dihydrochloride, azobisisoheptanenitrile, azobisisobutyronitrile, and 4,4'-azobis(4-cyanopentanoic acid), preferably azobisisobutyronitrile; The redox initiator includes any one or a combination of at least two of benzoyl peroxide, ammonium persulfate, potassium persulfate, sodium bisulfite, formaldehyde, ferrous sulfate, or sodium bisulfite, preferably potassium persulfate and sodium bisulfite.

10. The method for preparing amphoteric crosslinking polyacrylamide flocculant for nickel ore according to any one of claims 1 to 9, characterized in that, The preparation method includes the following steps: (1) Acrylamide crystals, anionic monomers, fluorinated cationic hydrophobic monomers, castor oil polyoxyethylene ether borate, cationic monomers, temperature-resistant and salt-resistant monomers, crosslinking agents, sodium perfluorononenoxybenzenesulfonate, co-solvents, 48% liquid alkali, and water are mixed and the pH value is adjusted to obtain a mixed solution. (2) Add chain transfer agent and mixed initiator to the mixed solution obtained in step (1) to carry out copolymerization reaction. After the copolymerization reaction is completed, granulate, dry and sieve the product to obtain the polyacrylamide flocculant for nickel ore amphoteric crosslinking.

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