An emulsion-type polymer flocculant for alumina red mud sedimentation and its preparation method

Abstract

The present invention relates to the field of sedimentation flocculants, specifically an emulsion-type polymer flocculant for alumina red mud sedimentation and its preparation method. First, a non-ionic polyacrylamide inverse emulsion is synthesized, and at the same time, a dithiocarbamate intermediate is synthesized. The above intermediate is introduced and bridged and crosslinked between polymer chains by the Mannich reaction; then, through oxime modification, a polymer emulsion with a complex crosslinked network structure containing dithiocarbamate groups, oxime acid groups, amide groups, and carboxyl groups is obtained. The oxime acid groups form adsorption on iron ions in the red mud, and the dithiocarbamate groups in the intermediate introduce strong adsorption on metals such as iron oxide in the red mud. The bridging effect causes the polymer chains in the emulsion to crosslink into a more complex three-dimensional network conformation. Through its bridging adsorption, surface adsorption, and charge adsorption effects, the solid-liquid separation efficiency in red mud sedimentation is greatly improved, and the sedimentation speed is significantly increased.

Description

Technical Field

[0001] The present invention relates to an emulsion-type polymer flocculant for alumina red mud sedimentation and a preparation method thereof, and is applied to the technical field of the preparation of flocculants for alumina red mud sedimentation in alumina production. Background Art

[0002] The sedimentation and separation of red mud are one of the important processes in the production of alumina by the Bayer process. The slurry digested in the Bayer process is mainly a suspension formed by red mud and sodium aluminate solution. There are very complex physical and chemical interactions between the particles contained in the red mud and between the red mud particles and the solution. The surface morphology, particle size distribution of the red mud particles, and the solid content and liquid-phase components of the red mud slurry all have a direct impact on the red mud sedimentation and separation process. The efficiency of solid-liquid separation directly determines the output rate of alumina. It is very difficult to achieve the ideal effect of rapid solid-liquid separation only by relying on separation equipment. By applying a flocculant, the speed of solid-liquid separation can be greatly increased, and the size and working load of the separation equipment can be reduced. Specifically, a polymer flocculant can cause effective aggregation between red mud particles through adsorption bridging, surface adsorption, and charge neutralization, forming larger particles, greatly accelerating the sedimentation speed, and thus realizing the efficient separation of red mud. Polymer flocculants containing hydroxamic acid functional groups have been widely used in the sedimentation and separation of red mud with excellent effects, mainly because hydroxamic acid has a rapid chelating effect on iron ions on the surface of red mud particles.

[0003] Patent No. CN110950415 B grafts polyacrylamide onto biological polysaccharides. The period for preparing biological polysaccharides by the enzymatic method is relatively long, and the introduction of sulfonic acid groups has a significantly worse sedimentation effect on red mud particles than hydroxamic acid groups. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of the prior art and provide an emulsion-type polymer flocculant for alumina red mud sedimentation and a preparation method thereof.

[0005] The technical solution adopted by the present invention is as follows: An emulsion-type polymer flocculant for alumina red mud sedimentation and a preparation method thereof, including the following steps:

[0006] An emulsion-type polymer flocculant for alumina red mud sedimentation, characterized in that the structural formula of the flocculant is: ;

[0007] wherein, -R is one of -CH2-CH2-, -CH2-CH2-CH2- or ; a1, a2, b1, b2, c1, c2 are positive integers greater than 1, and d1, d2 are positive integers.

[0008] A preparation method of an emulsion-type polymer flocculant for alumina red mud sedimentation, characterized by comprising the following steps:

[0009] S1. Emulsion polymerization process:

[0010] 1.1 Preparation of the aqueous phase: By mass, dissolve 190 - 220 parts of acrylamide in 240 - 260 parts of deionized water, add 5 - 10 parts of the co-solvent anhydrous sodium acetate, 0.01 - 0.02 parts of ammonium ferrous sulfate, add 0.001 - 0.002 parts of water-soluble azo, and adjust the pH to 6 - 8 with citric acid, and stir well to dissolve to obtain an aqueous phase solution;

[0011] 1.2 Preparation of the oil phase: By mass, while stirring, add a composite non-ionic emulsifier to 150 - 170 parts of white oil. The composite non-ionic emulsifier includes 8 - 10 parts of Span emulsifier, 2 - 4 parts of Tween emulsifier, 4 - 6 parts of fatty alcohol polyoxyethylene ether emulsifier, and 4 - 6 parts of fatty amine polyoxyethylene ether emulsifier. After the above composite non-ionic emulsifier is fully mixed and uniform, add 0.002 - 0.004 parts of oil-soluble azo and dissolve it fully;

[0012] 1.3 Polymerization reaction: Slowly add the aqueous phase solution prepared in 1.1 above to the oil phase prepared in 1.2 with rapid stirring. After adding, continue to stir for 5 minutes; perform 1 minute of full shear emulsification with an emulsifying pump to form a water-in-oil emulsion with a characteristic viscosity, and then blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an oxygen-free environment under nitrogen protection; adopt an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.004 - 0.008 parts of peroxide oxidant by mass; after stirring for 5 minutes, start dropping a 0.5% - 1% reducing agent solution, initiate at room temperature, control the temperature at 45 - 48 °C until the reaction ends, and cool to room temperature to obtain a light yellow non-ionic polyacrylamide reverse emulsion;

[0013] S2. Synthesis of dithiocarbamate intermediates:

[0014] In a four-necked flask, by mass, add 5 - 7 parts of a short carbon chain diamine and 20 parts of deionized water, stir to dissolve, heat and control the temperature at 20 - 25 °C, and use a dropping funnel to drop 8 - 12 parts of carbon disulfide within 30 minutes. After the dropping is completed, raise the temperature to 30 °C, and slowly add 30 - 35 parts of 20% sodium hydroxide by mass while stirring. When dropping the sodium hydroxide solution, continuously track and detect the pH value of the reaction solution and keep the pH value between 9 - 10. After the sodium hydroxide is added, continue the reaction for 30 minutes. After completion, filter and dry to obtain dithiocarbamate intermediates;

[0015] S3. Mannich reaction process:

[0016] By mass parts, add 8 - 15 parts of the dithiocarbamate intermediate of the above S2 into a three-necked flask, dissolve it in 30 - 50 parts of deionized water, then add it into 600 - 650 parts of the non-ionic polyacrylamide inverse emulsion of the above S1 and stir evenly. Heat up to 40 °C and keep stirring for 15 minutes, then heat up to 60 °C and stir for 30 minutes; divide 5 parts of 37% formaldehyde solution into 3 equal portions and add them into the three-necked flask at intervals of 10 minutes each time, then adjust the pH to 6.0 with hydrochloric acid, heat up to 70 °C and start reacting for 5 hours to obtain a Mannich reaction-modified emulsion;

[0017] S4. Oxime reaction process:

[0018] 4.1 Preparation of hydroxylamine alkaline solution: By mass parts, dissolve 25 - 30 parts of the high-temperature anti-degradation stabilizer sodium thiosulfate and 30 - 50 parts of hydroxylamine hydrochloride in 60 - 80 parts of deionized water, add 30 - 45 parts of a 50% sodium hydroxide solution by mass fraction for neutralization, and ensure that the temperature of the dissolved aqueous phase does not exceed 25 °C during the dissolution process to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0019] 4.2 By mass parts, add 4 - 6 parts of the emulsifier for oxime modification into 35 - 40 parts of white oil, fully mix and dissolve, then gradually add the above S3 Mannich reaction-modified emulsion, and then slowly add the above-prepared hydroxylamine alkaline solution and add 111 parts of 50% sodium hydroxide by mass fraction and stir well. Control the low-temperature oxime reaction at 40 - 48 °C for 5 - 6 hours to obtain an oxime-modified emulsion;

[0020] S5. Emulsion phase inversion process:

[0021] Add the emulsion after S4 oxime modification, by mass parts, add 30 - 35 parts of an alkylphenol polyoxyethylene ether demulsifier and 10 - 15 parts of a non-ionic isomeric alcohol polyoxyethylene ether demulsifier for phase inversion to obtain an oxime acid-modified polyacrylamide inverse emulsion flocculant.

[0022] Furthermore, the water-soluble azo is one or more of azodiisobutyramidine hydrochloride and azodiisobimidazoline hydrochloride; the oil-soluble azo is one or more of azodiisobutyronitrile and azodiisooctanenitrile.

[0023] Furthermore, the short-chain diamine is one or more of ethylenediamine, 1,3-propanediamine, and 1,2-propanediamine.

[0024] Further, the white oil is one or more of No. 3 white oil and No. 5 white oil; the Span emulsifier is one or more of SPAN60, SPAN65, and SPAN80, the Tween emulsifier is one or more of TWEEN40, TWEEN60, TWEEN80, and TWEEN81, the fatty alcohol polyoxyethylene ether emulsifier is one or more of AEO-2 and AEO-3, and the fatty amine polyoxyethylene ether emulsifier is one or more of AC-1205 and AC-1805.

[0025] Further, the peroxide oxidant is one or more of tert-butyl hydroperoxide, ammonium persulfate, and sodium persulfate; the reducing agent is one or more of sodium metabisulfite, sodium bisulfite, and potassium bisulfite.

[0026] Further, the emulsifier for oxime modification is one or more of cetyl palmitate, cetearyl alcohol polyether-12, and glyceryl stearate.

[0027] Further, the alkylphenol polyoxyethylene ether demulsifier is one or more of octylphenol polyoxyethylene ether and nonylphenol polyoxyethylene ether; the nonionic isomeric alcohol polyoxyethylene ether demulsifier is the BASF isomeric alcohol polyoxyethylene ether Lutensol XP series, preferably one or more of Lutensol XP79, XP89, and XP99.

[0028] In the present invention, a nonionic polyacrylamide inverse emulsion is first synthesized, and then a bis(dithiocarbamate) intermediate is synthesized. The Mannich reaction is used to not only graft the intermediate onto the polymer chain but also bridge between the polymer chains to form a self-crosslinked polyacrylamide; then the above self-crosslinked polymer is subjected to oxime modification, and finally an emulsion-type polyacrylamide for alumina red mud sedimentation is obtained after phase inversion.

[0029] In addition to containing a large number of oxime acid groups, the present invention also grafts and introduces bis(dithiocarbamate) groups that also have strong adsorption to red mud particles, which can effectively capture various heavy metal ions. The sulfur atom in the dithiocarbamate has a lone pair of electrons and is easily polarized to generate a negative electric field. The dithiocarbamate group can capture cations (iron ions) and form a cross-linked network metal ion chelate.

[0030] At the same time, its bridging and grafting effect causes cross-linking between the polymer chains, and finally a polyacrylamide emulsion with a high molecular weight three-dimensional network structure can quickly and effectively intercept and capture red mud particles, significantly improving the red mud sedimentation efficiency and significantly reducing the content of suspended matter in the overflow supernatant. Specific embodiments

[0031] Example 1:

[0032] S1. Emulsion polymerization process:

[0033] 1.1 Preparation of aqueous phase: By mass fraction, dissolve 201.2 parts of acrylamide in 253.1 parts of deionized water, add 6.3 parts of co-solvent sodium acetate anhydrous and 0.015 parts of ammonium ferrous sulfate, add 0.0012 parts of azobisisobutyramidine hydrochloride, adjust the pH to 7.0 with citric acid, and stir well to dissolve to obtain an aqueous phase solution;

[0034] 1.2 Preparation of oil phase: By mass fraction, add a composite non-ionic emulsifier to 159.3 parts of white oil No. 3 while stirring. The composite non-ionic emulsifier includes 9.8 parts of SPAN80, 3.3 parts of TWEEN80, 4.6 parts of AEO-2 and 5.2 parts of AC-1205. After the above composite non-ionic emulsifier is fully mixed and uniform, add 0.0025 parts of azobisisobutyronitrile and dissolve it fully;

[0035] 1.3 Polymerization reaction: Slowly add the aqueous phase solution prepared in 1.1 above to the oil phase prepared in 1.2 with rapid stirring. After adding, continue to stir for 5 minutes; perform 1 minute of sufficient shear emulsification with an emulsifying pump to form a water-in-oil emulsion with an intrinsic viscosity. Blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an anaerobic environment under nitrogen protection; use an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.005 parts by mass fraction of tert-butyl hydroperoxide; stir for 5 minutes, then start to dropwise add a 0.5% sodium metabisulfite solution, initiate at room temperature, control the temperature at 46 °C until the reaction ends, and cool to room temperature to obtain a pale yellow non-ionic polyacrylamide inverse emulsion;

[0036] S2. Synthesis of sodium 1,2-ethylenedithiocarbamate intermediate:

[0037] By mass fraction, add 5.8 parts of ethylenediamine and 20 parts of deionized water to a four-necked flask. After stirring and dissolving, heat and control the temperature at 20 - 25 °C, and add 10 parts of carbon disulfide dropwise with a dropping funnel within 30 minutes. After the addition is completed, raise the temperature to 30 °C, and slowly add 30 parts of 20% sodium hydroxide solution by mass fraction while stirring. When adding the sodium hydroxide solution, continuously track and detect the pH value of the reaction solution and keep it at about 9.5. Continue the reaction for 30 minutes after the addition of sodium hydroxide is completed, and obtain the sodium 1,2-ethylenedithiocarbamate intermediate after the reaction ends;

[0038] S3. Mannich reaction process:

[0039] By mass fraction, add 8.7 parts of the sodium ethylenedithiocarbamate intermediate of the above S2 to a three-necked flask, dissolve it in 30 parts of deionized water, then gradually add it to 640 parts of the non-ionic polyacrylamide inverse emulsion of S1 and stir evenly. Heat up to 40 °C and keep stirring for 15 minutes, then heat up to 60 °C and stir for 30 minutes; divide 5 parts of 37% formaldehyde solution into 3 equal portions and add them to the three-necked flask at intervals of 10 minutes each time, then adjust the pH to 6.0 with hydrochloric acid, heat up to 70 °C and start reacting for 5 hours to obtain a Mannich reaction-modified emulsion;

[0040] S4. Oxime reaction process:

[0041] 4.1 Preparation of hydroxylamine alkaline solution: By mass fraction, dissolve 27 parts of the high-temperature anti-degradation stabilizer sodium thiosulfate and 43 parts of hydroxylamine hydrochloride in 79 parts of deionized water, add 40 parts of a 50% sodium hydroxide solution by mass fraction for neutralization, and ensure that the temperature of the dissolved aqueous phase does not exceed 25 °C during the dissolution process to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0042] 4.2 By mass fraction, add 4.6 parts of the emulsifier cetyl palmitate for oxime modification to 37 parts of white oil No. 3, fully mix and dissolve, then gradually add the above-mentioned S3 Mannich reaction-modified emulsion, and then slowly add the above-prepared hydroxylamine alkaline solution and add 111 parts of 50% sodium hydroxide by mass fraction and stir well. Control the low-temperature oxime reaction at 46 °C for 5 hours to obtain an oxime-modified emulsion;

[0043] S5. Emulsion phase inversion process:

[0044] Add the emulsion after S4 oxime modification, by mass fraction, add 32 parts of the demulsifier nonylphenol polyoxyethylene ether and 11 parts of Lutensol XP79 for phase inversion to obtain an oxime acid-modified polyacrylamide inverse emulsion flocculant.

[0045] Example 2:

[0046] S1. Emulsion polymerization process:

[0047] 1.1 Preparation of the aqueous phase: By mass fraction, dissolve 198.5 parts of acrylamide in 253.1 parts of deionized water, add 6.3 parts of the co-solvent anhydrous sodium acetate, 0.015 parts of ammonium ferrous sulfate, add 0.0012 parts of 2,2'-azobis(2-methylpropionamidine) dihydrochloride, adjust the pH to 7.0 with citric acid, and stir well to dissolve to obtain an aqueous phase solution;

[0048] 1.2 Preparation of the oil phase: By mass fraction, while stirring, add a composite non-ionic emulsifier to 159.3 parts of white oil No. 3. The composite non-ionic emulsifier includes 10.0 parts of SPAN80, 3.1 parts of TWEEN81, 4.4 parts of AEO-3, and 5.4 parts of AC-1805. After the above composite non-ionic emulsifier is fully mixed and homogenized, add 0.0025 parts of azodiisobutyronitrile and dissolve it fully;

[0049] 1.3 Polymerization reaction: Slowly add the aqueous solution prepared in 1.1 above to the oil phase prepared in 1.2 above under rapid stirring. After the addition is complete, continue stirring for 5 minutes; use an emulsifying pump to perform sufficient shear emulsification for 1 minute to form a water-in-oil emulsion with an intrinsic viscosity. Blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an oxygen-free environment under nitrogen protection; adopt an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.008 parts of ammonium persulfate; after stirring for 5 minutes, start dropping a 0.5% sodium metabisulfite solution, initiate at room temperature, control the temperature at 45 °C until the reaction ends, and cool to room temperature to obtain a light yellow non-ionic polyacrylamide inverse emulsion;

[0050] S2. Synthesis of the intermediate sodium 1,2-ethylenebis(dithiocarbamate):

[0051] In a four-necked flask, add 6.5 parts of ethylenediamine and 20 parts of deionized water, stir to dissolve, heat and control the temperature at 20 - 25 °C, and use a dropping funnel to drop 10 parts of carbon disulfide within 30 minutes. After the dropping is complete, raise the temperature to 30 °C, and slowly add 30 parts of a 20% sodium hydroxide solution by mass fraction while stirring. When dropping the sodium hydroxide solution, continuously monitor and detect the pH value of the reaction solution and keep it at about 9.5. After the addition of sodium hydroxide is complete, continue the reaction for 30 minutes to obtain the intermediate sodium 1,2-ethylenebis(dithiocarbamate);

[0052] S3. Mannich reaction process:

[0053] By mass fraction, add 11.5 parts of the intermediate sodium 1,2-ethylenebis(dithiocarbamate) prepared in S2 above to a three-necked flask, dissolve it in 30 parts of deionized water, then gradually add it to 640 parts of the S1 non-ionic polyacrylamide inverse emulsion and stir evenly. Raise the temperature to 40 °C and keep stirring for 15 minutes, then raise the temperature to 60 °C and stir for 30 minutes; add 5 parts of a 37% formaldehyde solution evenly in 3 portions, with an interval of 10 minutes each time, then adjust the pH to 6.0 with hydrochloric acid, raise the temperature to 70 °C and start the reaction for 5 hours to obtain a Mannich reaction-modified emulsion;

[0054] S4. Oxime reaction process:

[0055] 4.1 Preparation of hydroxylamine alkaline solution: Dissolve 27 parts of high temperature anti-degradation stabilizer sodium thiosulfate and 38 parts of hydroxylamine hydrochloride in 78 parts of deionized water by mass, and add 34 parts of 50% sodium hydroxide solution by mass to neutralize. During the dissolution process, ensure that the temperature of the dissolved water phase does not exceed 25°C to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0056] 4.2 According to the mass fraction, 4.6 parts of cetyl palmitate, an emulsifier for hydroximation modification, are added to 37 parts of No. 3 white oil, and after being fully mixed and dissolved, the above-mentioned S3 Mannich reaction modified emulsion is gradually added, and then the above-mentioned prepared hydroxylamine alkaline solution is slowly added and 111 parts of 50% by mass sodium hydroxide are added and stirred fully, and the low-temperature hydroximation reaction is controlled at 46°C for 5-6 hours to obtain the hydroximation modified emulsion;

[0057] S5, emulsion phase transition process:

[0058] The S4 hydroxamic acid modified emulsion was added with 31 parts of demulsifier octylphenol polyoxyethylene ether and 12 parts of Lutensol XP89 by weight for phase inversion to obtain a hydroxamic acid modified polyacrylamide reverse emulsion flocculant.

[0059] Embodiment 3:

[0060] S1. Emulsion polymerization process:

[0061] 1.1 Preparation of aqueous phase: Dissolve 199.3 parts of acrylamide in 253.1 parts of deionized water, add 6.3 parts of anhydrous sodium acetate as a co-solvent, 0.015 parts of ammonium ferrous sulfate, add 0.0012 parts of azobisisobutylamidine hydrochloride, adjust the pH to 7.0 with citric acid, stir and dissolve thoroughly to obtain an aqueous phase solution;

[0062] 1.2 Preparation of oil phase: by mass, add composite nonionic emulsifier to 159.2 parts of No. 3 white oil while stirring. The composite nonionic emulsifier includes 9.8 parts of SPAN80, 3.3 parts of TWEEN80, 4.6 parts of AEO-2 and 5.2 parts of AC-1205. After the composite nonionic emulsifier is fully mixed, add 0.0025 parts of azobisisobutyronitrile and fully dissolve it;

[0063] 1.3 Polymerization reaction: Slowly add the aqueous solution prepared in 1.1 above to the rapidly stirred oil phase in 1.2 above. After the addition is complete, continue stirring for 5 minutes; use an emulsifying pump to perform sufficient shear emulsification for 1 minute to form a water-in-oil emulsion with a characteristic viscosity. Blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an oxygen-free environment under nitrogen protection; adopt an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.005 parts by mass of tert-butyl hydroperoxide; after stirring for 5 minutes, start dropping in a 0.5% sodium metabisulfite solution, initiate at room temperature, control the temperature at 45 °C until the reaction ends, and cool to room temperature to obtain a light yellow non-ionic polyacrylamide inverse emulsion;

[0064] S2. Synthesis of sodium 1,2-propylenedithiocarbamate intermediate:

[0065] By mass, add 6.2 parts of 1,2-propanediamine and 20 parts of deionized water to a four-necked flask. After stirring and dissolving, heat and control the temperature at 20 - 25 °C, and use a dropping funnel to drop 10 parts of carbon disulfide within 30 minutes. After the dropping is complete, raise the temperature to 30 °C, and slowly add 30 parts of 20% sodium hydroxide by mass while stirring. During the addition of the sodium hydroxide solution, continuously track and detect the pH value of the reaction solution and maintain it at about 9.5. After the addition of sodium hydroxide is complete, continue the reaction for 30 minutes to obtain the sodium 1,2-propylenedithiocarbamate intermediate;

[0066] S3. Mannich reaction process:

[0067] By mass, add 10.6 parts of the sodium 1,2-propylenedithiocarbamate intermediate in S2 above to a three-necked flask, dissolve it in 30 parts of deionized water, then gradually add it to 640 parts of the S1 non-ionic polyacrylamide inverse emulsion and stir evenly. Raise the temperature to 40 °C and keep stirring for 15 minutes, then raise the temperature to 60 °C and stir for 30 minutes; add 5 parts of 37% formaldehyde solution evenly in 3 portions, with an interval of 10 minutes each time, then adjust the pH to 6.0 with hydrochloric acid, raise the temperature to 70 °C and start the reaction for 5 hours to obtain a Mannich reaction-modified emulsion;

[0068] S4. Oxime reaction process:

[0069] 4.1 Preparation of hydroxylamine alkaline solution: By mass, dissolve 28 parts of high-temperature anti-degradation stabilizer sodium thiosulfate and 41 parts of hydroxylamine hydrochloride in 68 parts of deionized water, add 40 parts of 50% sodium hydroxide solution by mass for neutralization, and ensure that the temperature of the dissolved aqueous phase does not exceed 25 °C during the dissolution process to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0070] 4.2 By mass parts, add 4.6 parts of cetyl palmitate, an emulsifier for oxime modification, to 37 parts of white oil No. 3. After fully mixing and dissolving, gradually add the emulsion modified by the Mannich reaction in S3 above. Then slowly add the prepared hydroxylamine alkaline solution above and add 111 parts of sodium hydroxide with a mass fraction of 50%, and stir well. Control the low-temperature oxime reaction at 46 °C for 5 - 6 hours to obtain the emulsion after oxime modification;

[0071] S5. Emulsion phase inversion process:

[0072] Add the emulsion after oxime modification in S4, by mass parts, add 32 parts of nonylphenol polyoxyethylene ether, a demulsifier, and 11 parts of Lutensol XP79 for phase inversion to obtain an inverse emulsion flocculant of oxime acid modified polyacrylamide.

[0073] Example 4:

[0074] S1. Emulsion polymerization process:

[0075] 1.1 Preparation of the aqueous phase: By mass parts, dissolve 197.2 parts of acrylamide in 253.1 parts of deionized water, add 6.3 parts of co-solvent anhydrous sodium acetate and 0.015 parts of ammonium ferrous sulfate. Add 0.0012 parts of 2,2'-azobis(2-methylpropionamidine) dihydrochloride, and adjust the pH to 7.0 with citric acid, and stir well to dissolve to obtain an aqueous phase solution;

[0076] 1.2 Preparation of the oil phase: By mass parts, while stirring, add a composite non-ionic emulsifier to 159.3 parts of white oil No. 3. The composite non-ionic emulsifier includes 10.0 parts of SPAN80, 3.1 parts of TWEEN81, 4.4 parts of AEO-3 and 5.4 parts of AC-1805. After the above composite non-ionic emulsifier is fully mixed and uniform, add 0.0025 parts of 2,2'-azobis(2,4-dimethylvaleronitrile), and dissolve it fully;

[0077] 1.3 Polymerization reaction: Slowly add the aqueous phase solution prepared in 1.1 above to the rapidly stirred oil phase in 1.2 above. After adding, continue to stir for 5 minutes; use an emulsifying pump for 1 minute of full shear emulsification to form a water-in-oil emulsion with an intrinsic viscosity. Blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an oxygen-free environment under nitrogen protection; use an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.008 parts of ammonium persulfate by mass parts; after stirring for 5 minutes, start to drop in a 0.5% sodium metabisulfite solution, initiate at room temperature, control the temperature at 45 °C until the reaction ends, and cool to room temperature to obtain a light yellow non-ionic polyacrylamide inverse emulsion;

[0078] S2. Synthesis of sodium 1,2-propylenedithiocarbamate intermediate:

[0079] In a four-necked flask, add 6.8 parts of 1,2-propylenediamine and 20 parts of deionized water by weight, stir and dissolve, heat and control the temperature at 20-25°C, use a dropping funnel to drop 10 parts of carbon disulfide within 30 minutes, raise the temperature to 30°C after the addition is completed, and slowly add 30 parts of 20% sodium hydroxide while stirring. When adding sodium hydroxide solution, continuously track and detect the pH value of the reaction solution and keep it at about 9.5. After the sodium hydroxide is added, continue the reaction for 30 minutes, and the reaction is completed to obtain the intermediate of 1,2-propylene dithiocarbamate disodium;

[0080] S3, Mannich reaction process:

[0081] 12.8 parts of the above-mentioned disodium 1,2-propylenebisdithiocarbamate intermediate of S2 were added to a three-necked flask by mass, and dissolved in 30 parts of deionized water, and then 640 parts of S1 non-ionic polyacrylamide reverse emulsion were gradually added and stirred evenly, and the temperature was raised to 40°C and stirred for 15 minutes, and then the temperature was raised to 60°C and stirred for 30 minutes; 5 parts of 37% formaldehyde solution were added to the three-necked flask in 3 times, each time with an interval of 10 minutes, and then the pH was adjusted to 6.0 with hydrochloric acid, and the temperature was raised to 70°C to start the reaction for 5 hours to obtain a Mannich reaction modified emulsion;

[0082] S4, hydroximation reaction process:

[0083] 4.1 Preparation of hydroxylamine alkaline solution: Dissolve 27 parts of high temperature anti-degradation stabilizer sodium thiosulfate and 36 parts of hydroxylamine hydrochloride in 79 parts of deionized water by mass, and add 35 parts of 50% sodium hydroxide solution by mass to neutralize. During the dissolution process, ensure that the temperature of the dissolved water phase does not exceed 25°C to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0084] 4.2 According to the mass fraction, 4.6 parts of cetyl palmitate, an emulsifier for hydroximation modification, are added to 37 parts of No. 3 white oil, and after being fully mixed and dissolved, the above-mentioned S3 Mannich reaction modified emulsion is gradually added, and then the above-mentioned prepared hydroxylamine alkaline solution is slowly added and 111 parts of 50% by mass sodium hydroxide are added and stirred fully, and the low-temperature hydroximation reaction is controlled at 46°C for 5 hours to obtain the hydroximation modified emulsion;

[0085] S5, emulsion phase transition process:

[0086] 31 parts of demulsifier octylphenol polyoxyethylene ether and 12 parts of Lutensol XP89 were added to the S4 hydroxamic acid modified emulsion by weight to perform phase inversion to obtain a hydroxamic acid modified polyacrylamide inverse emulsion flocculant.

[0087] Embodiment 5:

[0088] S1. Emulsion polymerization process:

[0089] 1.1 Preparation of aqueous phase: By mass fraction, dissolve 196.5 parts of acrylamide in 253.1 parts of deionized water, add 6.3 parts of co-solvent sodium acetate anhydrous and 0.015 parts of ammonium ferrous sulfate, add 0.0012 parts of azodiisobutyramidine hydrochloride, adjust the pH to 7.0 with citric acid, and stir well to dissolve to obtain an aqueous phase solution;

[0090] 1.2 Preparation of oil phase: By mass fraction, while stirring 159.2 parts of white oil No. 3, add a composite non-ionic emulsifier. The composite non-ionic emulsifier includes 9.8 parts of SPAN80, 3.3 parts of TWEEN80, 4.6 parts of AEO-2 and 5.2 parts of AC-1205. After the above composite non-ionic emulsifier is fully mixed and uniform, add 0.0025 parts of azodiisobutyronitrile and dissolve it fully;

[0091] 1.3 Polymerization reaction: Slowly add the aqueous phase solution prepared in 1.1 above to the rapidly stirred oil phase in 1.2 above. After adding, continue to stir for 5 minutes; perform sufficient shear emulsification with an emulsifying pump for 1 minute to form a water-in-oil emulsion with an intrinsic viscosity. Blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an anaerobic environment under nitrogen protection; adopt an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.005 parts of tert-butyl hydroperoxide by mass fraction; after stirring for 5 minutes, start to drip a 0.5% sodium metabisulfite solution, initiate at room temperature, control the temperature at 45 °C until the reaction ends, and cool to room temperature to obtain a light yellow non-ionic polyacrylamide inverse emulsion;

[0092] S2. Synthesis of sodium 1,3-propylenedithiocarbamate intermediate:

[0093] By mass fraction, add 6.5 parts of 1,3-propanediamine and 20 parts of deionized water to a four-necked flask. After stirring and dissolving, heat and control the temperature at 20 - 25 °C, and add 10 parts of carbon disulfide dropwise with a dropping funnel within 30 minutes. After the addition is completed, raise the temperature to 30 °C, and slowly add 30 parts of 20% sodium hydroxide by mass fraction while stirring. During the addition of the sodium hydroxide solution, continuously monitor and detect the pH value of the reaction solution and keep it at about 9.5. After the addition of sodium hydroxide is completed, continue the reaction for 30 minutes to obtain the sodium 1,3-propylenedithiocarbamate intermediate;

[0094] S3. Mannich reaction process:

[0095] By mass fraction, add 13.5 parts of the sodium 1,3-propylene bis(dithiocarbamate) intermediate of the above S2 into a three-necked flask, dissolve it in 30 parts of deionized water, then gradually add it into 640 parts of the S1 non-ionic polyacrylamide inverse emulsion and stir evenly. Heat up to 40 °C and keep stirring for 15 minutes, then heat up to 60 °C and stir for 30 minutes; Divide 5 parts of 37% formaldehyde solution into 3 equal portions and add them into the three-necked flask at intervals of 10 minutes each. Then adjust the pH to 6.0 with hydrochloric acid, heat up to 70 °C and start the reaction for 5 hours to obtain the Mannich reaction-modified emulsion;

[0096] S4. Oxime reaction process:

[0097] 4.1 Preparation of hydroxylamine alkaline solution: By mass fraction, dissolve 27 parts of the high-temperature anti-degradation stabilizer sodium thiosulfate and 42 parts of hydroxylamine hydrochloride in 79 parts of deionized water, add 40 parts of 50% sodium hydroxide solution by mass fraction for neutralization, and ensure that the temperature of the dissolved aqueous phase does not exceed 25 °C during the dissolution process to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0098] 4.2 By mass fraction, add 4.6 parts of the emulsifier cetyl palmitate for oxime modification into 37 parts of white oil No. 3. After fully mixing and dissolving, gradually add the above S3 Mannich reaction-modified emulsion, then slowly add the above-prepared hydroxylamine alkaline solution and add 111 parts of 50% sodium hydroxide by mass fraction and stir well. Control the low-temperature oxime reaction at 46 °C for 5 - 6 hours to obtain the oxime-modified emulsion;

[0099] S5. Emulsion phase inversion process:

[0100] Add the S4 oxime-modified emulsion, by mass fraction, add 32 parts of the demulsifier nonylphenol polyoxyethylene ether and 11 parts of Lutensol XP79 for phase inversion to obtain the oxime acid-modified polyacrylamide inverse emulsion flocculant.

[0101] Example 6:

[0102] S1. Emulsion polymerization process:

[0103] 1.1 Preparation of the aqueous phase: By mass fraction, dissolve 195.1 parts of acrylamide in 253.1 parts of deionized water, add 6.3 parts of the co-solvent sodium acetate anhydrous, 0.015 parts of ammonium ferrous sulfate, add 0.0012 parts of 2,2'-azobis(2-methylpropionamidine) dihydrochloride, adjust the pH to 7.0 with citric acid, and stir well to dissolve to obtain an aqueous phase solution;

[0104] 1.2 Preparation of the oil phase: By mass fraction, while stirring, add a composite non-ionic emulsifier to 159.3 parts of white oil No. 3. The composite non-ionic emulsifier includes 10.0 parts of SPAN80, 3.1 parts of TWEEN81, 4.4 parts of AEO-3, and 5.4 parts of AC-1805. After the above composite non-ionic emulsifier is fully mixed and homogenized, add 0.0025 parts of azodiisobutyronitrile and dissolve it fully;

[0105] 1.3 Polymerization reaction: Slowly add the aqueous solution prepared in 1.1 above to the oil phase in 1.2 above under rapid stirring. After the addition is complete, continue stirring for 5 minutes; Use an emulsifying pump to perform full shear emulsification for 1 minute to form a water-in-oil emulsion with an intrinsic viscosity. Blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an oxygen-free environment under nitrogen protection; Use an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.008 parts by mass fraction of ammonium persulfate; After stirring for 5 minutes, start dropping a 0.5% sodium metabisulfite solution and initiate at room temperature. Control the temperature at 45 - 48 °C until the reaction ends, and then cool to room temperature to obtain a light yellow non-ionic polyacrylamide inverse emulsion;

[0106] S2. Synthesis of the intermediate sodium 1,3-propylenedithiocarbamate:

[0107] By mass fraction, add 6.8 parts of 1,3-propanediamine and 20 parts of deionized water to a four-necked flask. After stirring and dissolving, heat and control the temperature at 20 - 25 °C. Use a dropping funnel to drop 10 parts of carbon disulfide within 30 minutes. After the dropping is complete, raise the temperature to 30 °C, and slowly add 30 parts of 20% sodium hydroxide by mass fraction while stirring. When dropping the sodium hydroxide solution, continuously track and detect the pH value of the reaction solution and keep it at about 9.5. After adding the sodium hydroxide, continue the reaction for 30 minutes to obtain the intermediate sodium 1,3-propylenedithiocarbamate;

[0108] S3. Mannich reaction process:

[0109] By mass fraction, add 14.8 parts of the intermediate sodium 1,3-propylenedithiocarbamate in S2 above to a three-necked flask, dissolve it in 30 parts of deionized water, then gradually add 640 parts of the S1 non-ionic polyacrylamide inverse emulsion and stir evenly. Raise the temperature to 40 °C and keep stirring for 15 minutes, then raise the temperature to 60 °C and stir for 30 minutes; Divide 5 parts of 37% formaldehyde solution into 3 equal portions and add them to the three-necked flask at intervals of 10 minutes each. Then adjust the pH to 6.0 with hydrochloric acid, raise the temperature to 70 °C and start the reaction for 5 hours to obtain a Mannich reaction-modified emulsion;

[0110] S4. Oxime reaction process:

[0111] 4.1 Preparation of hydroxylamine alkaline solution: Dissolve 27 parts of high temperature anti-degradation stabilizer sodium thiosulfate and 36 parts of hydroxylamine hydrochloride in 80 parts of deionized water by mass, and add 34 parts of 50% sodium hydroxide solution for neutralization. During the dissolution process, ensure that the temperature of the dissolved water phase does not exceed 25°C to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0112] 4.2 According to the mass fraction, 4.6 parts of cetyl palmitate, an emulsifier for hydroximation modification, are added to 37 parts of No. 3 white oil, and after being fully mixed and dissolved, the above-mentioned S3 Mannich reaction modified emulsion is gradually added, and then the above-mentioned prepared hydroxylamine alkaline solution is slowly added and 111 parts of 50% by mass sodium hydroxide are added and stirred fully, and the low-temperature hydroximation reaction is controlled at 46°C for 5-6 hours to obtain the hydroximation modified emulsion;

[0113] S5, emulsion phase transition process:

[0114] 31 parts of demulsifier octylphenol polyoxyethylene ether and 12 parts of Lutensol XP89 were added to the S4 hydroxamic acid modified emulsion by weight to perform phase inversion to obtain a hydroxamic acid modified polyacrylamide inverse emulsion flocculant.

[0115] Comparative Example 1:

[0116] S1. Emulsion polymerization process:

[0117] 1.1 Preparation of aqueous phase: Dissolve 210 parts of acrylamide in 253.1 parts of deionized water, add 6.3 parts of anhydrous sodium acetate as a co-solvent, 0.015 parts of ammonium ferrous sulfate, add 0.0012 parts of azobisisobutylamidine hydrochloride, adjust the pH to 7.0 with citric acid, stir and dissolve thoroughly to obtain an aqueous phase solution;

[0118] 1.2 Preparation of oil phase: by mass, add composite nonionic emulsifier to 159.3 parts of No. 3 white oil while stirring. The composite nonionic emulsifier includes 9.8 parts of SPAN80, 3.3 parts of TWEEN80, 4.6 parts of AEO-2 and 5.2 parts of AC-1205. After the composite nonionic emulsifier is fully mixed, add 0.0025 parts of azobisisobutyronitrile and fully dissolve it;

[0119] 1.3 Polymerization reaction: Slowly add the aqueous solution prepared in 1.1 above to the rapidly stirred oil phase in 1.2 above. After the addition is complete, continue stirring for 5 minutes; use an emulsifying pump to perform sufficient shear emulsification for 1 minute to form a water-in-oil emulsion with intrinsic viscosity. Blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an oxygen-free environment under nitrogen protection; adopt an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.005 parts by mass of tert-butyl hydroperoxide; after stirring for 5 minutes, start dropping in a 0.5% sodium metabisulfite solution, initiate at room temperature, control the temperature at 45 - 48 °C until the reaction ends, and cool to room temperature to obtain a light yellow non-ionic polyacrylamide inverse emulsion;

[0120] S2. Process of oxime reaction:

[0121] 2.1 Preparation of hydroxylamine alkaline solution: By mass fraction, dissolve 27 parts of high-temperature anti-degradation stabilizer sodium thiosulfate and 43 parts of hydroxylamine hydrochloride in 79 parts of deionized water, add 40 parts of 50% sodium hydroxide solution by mass fraction for neutralization, and ensure that the temperature of the dissolved aqueous phase does not exceed 25 °C during the dissolution process to prepare a hydroxylamine alkaline solution with a pH of 12.5;

[0122] 2.2 By mass fraction, add 4.6 parts of cetyl alcohol palmitate, an emulsifier for oxime modification, to 37 parts of white oil No. 3. After fully mixing and dissolving, gradually add the emulsion in step 1.3 above, and then slowly add the above-prepared hydroxylamine alkaline solution and add 111 parts of 50% sodium hydroxide by mass fraction and stir well. Control the low-temperature oxime reaction at 46 °C for 5 hours to obtain an oxime-modified emulsion;

[0123] S3. Process of emulsion phase inversion:

[0124] Add the emulsion modified by oxime in S2, by mass fraction, add 32 parts of demulsifier nonylphenol polyoxyethylene ether and 12 parts of Lutensol XP79 for phase inversion to obtain an acrylamide oxime-modified polyacrylamide inverse emulsion flocculant.

[0125] Comparative Example 2:

[0126] S1. Emulsion polymerization process:

[0127] Same as S1 in Example 3

[0128] S2. Synthesis of sodium 1,4-butylenedithiocarbamate intermediate:

[0129] By mass fraction, in a four-necked flask, add 6.2 parts of 1,4-diaminobutane and 20 parts of deionized water. After stirring and dissolving, heat and control the temperature at 20 - 25 °C. Use a dropping funnel to add 10 parts of carbon disulfide within 30 minutes. After the addition is complete, raise the temperature to 30 °C, and slowly add 30 parts of sodium hydroxide with a mass fraction of 20% while stirring. When adding the sodium hydroxide solution, continuously track and detect the pH value of the reaction solution and maintain it at about 9.5. After the addition of sodium hydroxide is complete, continue the reaction for 30 minutes to obtain the intermediate of sodium 1,4-butylenedithiocarbamate;

[0130] S3. Mannich reaction process:

[0131] By mass fraction, add 10.6 parts of the intermediate of sodium 1,4-butylenedithiocarbamate in S2 above to a three-necked flask, dissolve it in 30 parts of deionized water, and then gradually add it to 640 parts of the S1 non-ionic polyacrylamide inverse emulsion and stir evenly. Raise the temperature to 40 °C and keep stirring for 15 minutes, then raise the temperature to 60 °C and stir for 30 minutes; Add 5 parts of 37% formaldehyde solution evenly in 3 times to the three-necked flask, with an interval of 10 minutes each time, and then adjust the pH to 6.0 with hydrochloric acid. Raise the temperature to 70 °C and start the reaction for 5 hours to obtain the Mannich reaction-modified emulsion;

[0132] S4 and S5 are the same as S4 and S5 in Example 3.

[0133] Application performance test

[0134] Compare and test Examples 1, 2, 3, 4, 5, 6 and Comparative Examples 1 and 2.

[0135] (1) Preparation of 10 g / L alkaline water:

[0136] Experiments have shown that when the water contains 10 - 30 g / L of sodium hydroxide, the anionic emulsion can achieve the highest efficiency. Therefore, in this experiment, 10 g / L of sodium hydroxide alkaline water was prepared, that is, 1 liter of alkaline water containing 10 g / L of sodium hydroxide was prepared with deionized water.

[0137] Weigh 10 g of flaky sodium hydroxide in a plastic cup.

[0138] Add 500 ml of deionized water to a 1-liter flask.

[0139] Slowly add the flaky caustic soda to the water.

[0140] Stir with a magnetic stirrer.

[0141] Take out the stir bar, add deionized water to the beaker until it reaches 1 liter.

[0142] If cooling is required, the beaker can be cooled to room temperature and the water volume can be adjusted to 1 liter.

[0143] According to this method, prepare 8 portions of 10 g / L alkaline water.

[0144] (2) Preparation of the flocculant solution:

[0145] Add the emulsion flocculants of Examples 1, 2, 3, 4, 5, 6, Comparative Examples 1 and 2 respectively to the 8 prepared portions of 10 g / L alkaline water, so that the concentration of the emulsion in the alkaline water is 0.5%.

[0146] (3) Sedimentation experiment:

[0147] All the slurries to be tested were sampled on-site from a certain branch factory of Aluminum Corporation of China in Shandong and tested on-site. The slurry was taken from the feed of the separation tank and placed in a 1-liter graduated cylinder for testing, with a solid content of 80 g / L.

[0148] 3.1. Perform 5 rapid stirrings on the slurry in the graduated cylinder to achieve the purpose of slurry homogenization.

[0149] 3.2. Add 1 ml of the flocculant solution using a syringe.

[0150] 3.3. Use a stirrer to perform 6 medium-strength stirrings on the slurry with the added flocculant.

[0151] 3.4. Add the remaining 1 ml of the flocculant solution.

[0152] 3.5. Perform 4 medium-strength stirrings.

[0153] 3.6. Measure the time required from 900 ml to 700 ml.

[0154] 3.7. Measure the turbidity of the supernatant and the volume of the compressed mud layer after 3 minutes.

[0155] The experimental data are shown in the following table.

[0156]

[0157] It can be seen from the above experimental data combined with the following table that the sedimentation rate of Examples 1-6 from 900 mL to 700 mL is significantly faster than that of the red mud of Comparative Examples 1 and 2, and the flocculation separation time is shortened to about 25-35%; at the same time, the thickness of the compressed mud layer in Examples 1-6 in the following table is significantly smaller, reduced by about 20-25%. The filtration time of vacuum filtration reflects the filtration performance of the treated thick liquor. The improvement of this index can increase the output of the leaf filter, reduce the filtration pressure and improve the service life of the filter cloth: in the following table, the filtration time of Examples 1-6 is significantly shorter than that of Comparative Examples 1 and 2, indicating that the flocculant has a stronger ability to capture fine particles and suspended matter, indicating that there are fewer fine particles in the supernatant.

[0158] The emulsion-type polymer flocculant for alumina red mud sedimentation described in the present invention, in addition to containing an oxime acid group as an effective metal chelating agent, also introduces a disodium alkylidene bisdithiocarbamate intermediate metal ion capturer with C2-C3, which also has a strong collecting ability for transition metal iron ions. At the same time, the disodium alkylidene bisdithiocarbamate intermediate is grafted and crosslinked between the polymer chains of polyacrylamide, has a more complex three-dimensional network structure in an alkaline aqueous solution, and has higher rheological properties. Using bridging adsorption, surface adsorption and charge adsorption, it generates a stronger flocculation ability and a faster sedimentation speed.

[0159] In comparison, for the flocculant in Comparative Example 1 containing only oxime acid, the sedimentation time becomes longer and the speed becomes slower, and at the same time, the thickness of the compressed mud layer is higher; although Comparative Example 2 has both an oxime acid group and a disodium 1,4-butylidene bisdithiocarbamate group as a capturer for transition metal iron, due to the decrease in the grafting crosslinking activity and yield of the disodium 1,4-butylidene bisdithiocarbamate group with the increase in the hydrocarbon chain length, the crosslinking degree between polyacrylamide molecules is reduced. Therefore, the red mud sedimentation speed is lower than that of Examples 1-6, the volume of the compressed mud layer at 3 minutes increases, the suction filtration time becomes longer, and the suspended matter in the supernatant is significantly more.

Claims

1. An emulsion-type polymer flocculant for alumina red mud sedimentation, characterized in that, Structural formula of the flocculant: ； wherein, -R is one of -CH2-CH2-, -CH2-CH2-CH2- ; a1, a2, b1, b2, c1, c2 are positive integers greater than 1, and d1, d2 are positive integers.

2. The preparation method of an emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 1, characterized in that, It includes the following steps: S1. Emulsion polymerization process: 1.1 Preparation of aqueous phase: By mass, dissolve 190 - 220 parts of acrylamide in 240 - 260 parts of deionized water, add 5 - 10 parts of cosolvent sodium acetate anhydrous, 0.01 - 0.02 parts of ammonium ferrous sulfate, add 0.001 - 0.002 parts of water-soluble azo, adjust the pH to 6 - 8 with citric acid, stir well to dissolve, and obtain an aqueous phase solution; 1.2 Preparation of oil phase: By mass, while stirring, add a composite non-ionic emulsifier to 150 - 170 parts of white oil. The composite non-ionic emulsifier includes 8 - 10 parts of Span emulsifier, 2 - 4 parts of Tween emulsifier, 4 - 6 parts of fatty alcohol polyoxyethylene ether emulsifier and 4 - 6 parts of fatty amine polyoxyethylene ether emulsifier. After the above composite non-ionic emulsifier is fully mixed and uniform, add 0.002 - 0.004 parts of oil-soluble azo and dissolve it fully; 1.3 Polymerization reaction: Slowly add the aqueous phase solution prepared in 1.1 above to the rapidly stirred oil phase in 1.2 above. After adding, continue to stir for 5 minutes; use an emulsifying pump for 1 minute of full shear emulsification to form a water-in-oil emulsion with an intrinsic viscosity. Then blow in nitrogen to displace the oxygen in the system to ensure that the entire polymerization reaction process is carried out in an oxygen-free environment under nitrogen protection; use an azo-redox composite initiation system. At room temperature, before the polymerization reaction, add 0.004 - 0.008 parts of peroxide oxidant by mass; stir for 5 minutes, then start to dropwise add a 0.5% - 1% reducing agent solution, initiate at room temperature, control the temperature at 45 - 48 °C until the reaction ends, and cool to room temperature to obtain a light yellow non-ionic polyacrylamide inverse emulsion; S2. Synthesis of dithiocarbamate intermediates: In a four-necked flask, by mass, add 5 - 7 parts of short carbon chain diamine and 20 parts of deionized water, stir to dissolve, heat and control the temperature at 20 - 25 °C, use a dropping funnel to drop 8 - 12 parts of carbon disulfide within 30 minutes. After the dropping is completed, raise the temperature to 30 °C, and slowly add 30 - 35 parts of 20% sodium hydroxide by mass while stirring. When dropping the sodium hydroxide solution, continuously track and detect the pH value of the reaction solution and keep the pH value between 9 - 10. After adding sodium hydroxide, continue to react for 30 minutes. After completion, filter and dry to obtain dithiocarbamate intermediates; S3. Mannich reaction process: By mass, add 8 - 15 parts of the dithiocarbamate intermediates in S2 above to a three-necked flask, dissolve in 30 - 50 parts of deionized water, then add it to 600 - 650 parts of the non-ionic polyacrylamide inverse emulsion in S1 above and stir evenly. Raise the temperature to 40 °C and keep stirring for 15 minutes, then raise the temperature to 60 °C and stir for 30 minutes; divide 5 parts of 37% formaldehyde solution into 3 equal parts and add them to the three-necked flask at intervals of 10 minutes each. Then adjust the pH to 6.0 with hydrochloric acid, raise the temperature to 70 °C and start to react for 5 hours to obtain a Mannich reaction modified emulsion; S4. Oxime reaction process: 4.1 Preparation of hydroxylamine alkaline solution: By mass fraction, dissolve 25 - 30 parts of high-temperature anti-degradation stabilizer sodium thiosulfate and 30 - 50 parts of hydroxylamine hydrochloride in 60 - 80 parts of deionized water, add 30 - 45 parts of 50% sodium hydroxide solution by mass fraction for neutralization, and ensure that the temperature of the dissolved aqueous phase does not exceed 25 °C during the dissolution process to prepare a hydroxylamine alkaline solution with a pH of 12.

5. 4.2 By mass fraction, add 4 - 6 parts of the emulsifier for oxime modification to 35 - 40 parts of white oil. After fully mixing and dissolving, gradually add the emulsion modified by the above S3 Mannich reaction, and then slowly add the above-prepared hydroxylamine alkaline solution and add 111 parts of 50% sodium hydroxide by mass fraction and stir well. Control the low-temperature oxime reaction at 40 - 48 °C for 5 - 6 hours to obtain the oxime-modified emulsion. S5. Emulsion phase inversion process: Add 30 - 35 parts of alkylphenol polyoxyethylene ether demulsifier and 10 - 15 parts of non-ionic isomeric alcohol polyoxyethylene ether demulsifier by mass fraction to the emulsion modified by S4 oxime to carry out phase inversion, and obtain the reverse emulsion flocculant of oxime acid-modified polyacrylamide.

3. The preparation method of the emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 2, characterized in that: The water-soluble azo is one or more of azodiisobutyramidine hydrochloride and azodiisobimidazoline hydrochloride; the oil-soluble azo is one or more of azodiisobutyronitrile and azodiisooctanenitrile.

4. The preparation method of the emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 2, characterized in that: The short-chain diamine is one or more of ethylenediamine, 1,3-propanediamine, and 1,2-propanediamine.

5. The preparation method of an emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 2, characterized in that: The white oil described in the above 1.2 is one or more of No. 3 white oil and No. 5 white oil; the Span emulsifier is one or more of SPAN60, SPAN65, and SPAN80, the Tween emulsifier is one or more of TWEEN40, TWEEN60, TWEEN80, and TWEEN81, the fatty alcohol polyoxyethylene ether emulsifier is one or more of AEO-2 and AEO-3, and the fatty amine polyoxyethylene ether emulsifier is one or more of AC-1205 and AC-1805.

6. The preparation method of the emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 2, characterized in that: The peroxide oxidant is one or more of tert-butyl hydroperoxide, ammonium persulfate, and sodium persulfate; the reducing agent is one or more of sodium metabisulfite, sodium bisulfite, and potassium bisulfite.

7. The preparation method of an emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 2, characterized in that: The emulsifier for oxime modification is one or more of cetyl palmitate, cetearyl alcohol polyether-12, and glyceryl stearate.

8. The preparation method of the emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 2, characterized in that: The alkylphenol polyoxyethylene ether demulsifier is one or two of octylphenol polyoxyethylene ether and nonylphenol polyoxyethylene ether; the non-ionic isomeric alcohol polyoxyethylene ether demulsifier is the BASF isomeric alcohol polyoxyethylene ether Lutensol XP series.

9. The preparation method of an emulsion-type polymer flocculant for alumina red mud sedimentation according to claim 8, characterized in that: The BASF isomeric alcohol polyoxyethylene ether Lutensol XP series is one or more of Lutensol XP79, XP89, and XP99.

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