A method for removing heavy metals from wet-process phosphoric acid

Abstract

The present application relates to a kind of methods for removing heavy metals in wet-process phosphoric acid, it is characterized in that comprising the following steps: (1) phosphorite is crushed, flotation pretreatment is mixed with sulfuric acid after 1:1.3-1.5 by mass ratio, under the condition of 80-87 ℃ 30-90 min reaction is formed slurry;(2) before slurry enters filter, to slurry pump before adding modifier and heavy metal removal agent;(3) the ore pulp is filtered to obtain dilute phosphoric acid, dilute phosphoric acid is settled, concentrated to obtain concentrated phosphoric acid crude product;Phosphoric acid crude product is settled, separated and purified, to obtain pure phosphoric acid.The present application is combined by using modifier and heavy metal removal agent, aims at realizing the synchronous efficient removal of multiple heavy metals, breaks through the industry problem of poor selectivity in acidic system and serious secondary pollution.

Description

Technical Field

[0001] This invention relates to a method for removing heavy metals from wet-process phosphoric acid, belonging to the field of phosphoric acid purification technology. Background Technology

[0002] Wet-process phosphoric acid, a core raw material in the phosphate chemical industry, suffers from high concentrations of harmful metals such as arsenic (As), cadmium (Cd), and copper (Cu) introduced from low- to medium-grade phosphate rock (As 30-200 ppm, Cd 5-50 ppm, Cu 20-150 ppm), severely hindering its high-value application. Existing removal technologies face three major bottlenecks: 1) As(III) is electrically neutral and difficult to capture in strongly acidic environments (pH 1-3); 2) Inorganic sulfide precipitation releases H2S with an arsenic removal rate of <40%; 3) Organic sulfides have low efficiency, high cost, and limited application sites. Meanwhile, the upgrading of standards for food-grade phosphoric acid (As ≤ 0.5 ppm) and high-end phosphate fertilizers (Cd ≤ 10 ppm) urgently necessitates the development of low-cost, one-step deep removal technologies.

[0003] The existing technology has the following drawbacks: 1. Traditional wet phosphoric acid removal of heavy metals mainly relies on the addition of inorganic sulfides and organic sulfides. The use of inorganic sulfides releases hydrogen sulfide, which poses a safety hazard and has a high cost. Although organic sulfides can effectively remove heavy metals, they have the problems of short efficiency and high cost.

[0004] 2. Existing purification methods, such as chemical precipitation, solvent extraction, and crystallization, are insufficient to effectively address the high heavy metal content in wet-process phosphoric acid, and cannot meet the production requirements for high-purity phosphoric acid.

[0005] 3. The current wet-process phosphoric acid process lacks an optimization and adjustment mechanism for key parameters, making it difficult to achieve better heavy metal removal and product quality, thus affecting the purity and quality of phosphoric acid.

[0006] 4. Existing technologies lack selective removal mechanisms for different types of heavy metal ions, making it difficult to achieve efficient extraction and removal of specific heavy metals.

[0007] 5. Traditional wet-process phosphoric acid production has high energy consumption and high production costs, making it difficult to meet the needs of large-scale industrial production. Summary of the Invention

[0008] The purpose of this invention is to overcome the safety hazards that may arise from the release of hydrogen sulfide from inorganic sulfides during the removal of heavy metals in wet phosphoric acid, as well as the low efficiency and high cost of organic sulfides. This invention provides a method for removing heavy metals from wet phosphoric acid. By using a modifier and a heavy metal removal agent in combination, this invention aims to achieve simultaneous and efficient removal of arsenic, cadmium, copper, etc., and overcome the industry problems of poor selectivity and serious secondary pollution in acidic systems.

[0009] The technical solution adopted in this invention is as follows: A method for removing heavy metals from wet-process phosphoric acid, characterized by comprising the following steps: (1) After crushing and pre-flotation treatment of phosphate rock, mix it with sulfuric acid at a mass ratio of 1:1.3-1.5 and react at 80-87℃ for 30-90 min to form a slurry; (2) Before the slurry enters the filter, a modifier and a heavy metal removal agent are added to the slurry pump; the modifier is a cosolvent and / or emulsifier, the cosolvent is one or a mixture of two or more of ethanol, propanol, n-butanol, isobutanol, n-octanol, and isooctanol, the emulsifier is one or a mixture of two or more of alkyl aromatic sulfonates, alkyl sulfonates, lignin sulfonates, sulfosuccinates, fatty alcohol polyoxyethylene ethers, stearates, phosphate esters, and quaternary ammonium salts; the heavy metal removal agent is one or a mixture of two or more of dialkyl dithiophosphate, dialkyl dithiophosphate ester, dialkyl dithiophosphoric acid, and dialkyl dithiophosphite. (3) The slurry is filtered to obtain dilute phosphoric acid. The dilute phosphoric acid is then settled and concentrated to obtain crude concentrated phosphoric acid. The crude phosphoric acid is then settled, separated and purified to obtain pure phosphoric acid.

[0010] The alkyl aromatic sulfonates are sodium dodecylbenzenesulfonate, calcium dodecylbenzenesulfonate, sodium xylenesulfonate, or calcium xylenesulfonate; the alkyl sulfonates are sodium secondary alkyl sulfonate, sodium dodecyl sulfonate, or α-sulfonyl fatty acid methyl ester; the lignin sulfonates are sodium sulfate lignin sulfonate or sodium lignin sulfonate; the sulfosuccinates are sodium dibutyl sulfosuccinate, sodium diisobutyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium diisooctyl sulfosuccinate, sodium ditridecyl sulfosuccinate, or polysiloxane sulfosuccinate; the fatty alcohol polyoxyethylene ethers are AEO-3, AEO-7, or TX-10; the stearates are sodium stearate or calcium stearate; the phosphate esters are polyethylene glycol or sodium lauryl phosphate; and the quaternary ammonium salts are didecyl dimethyl ammonium chloride or benzalkonium chloride.

[0011] Add 1.5-15 kg of heavy metal removal agent per ton of slurry. The amount of modifier added should be based on a mass ratio of modifier to heavy metal removal agent of 1:20-50.

[0012] The amount of cosolvent added is 0.002-0.03% of the slurry mass, and the amount of emulsifier added is 0.003-0.02%.

[0013] The modifier and heavy metal removal agent react with the slurry at a temperature of 70-80℃ for a time of 5-30 seconds. The modifier and heavy metal removal agent are mixed with the slurry in the conveying pipeline, where the slurry temperature is 70-80℃. The reaction time is limited by the pipeline length and pump flow rate, generally between 5-30 seconds. Existing single-use heavy metal removal aids cannot achieve the removal effect in such a short time.

[0014] The heavy metal residues in the wet-process phosphoric acid obtained in step (3) are Cd≤3ppm, As≤4ppm, and Cu≤0.1ppm.

[0015] Compared with the prior art, the method of the present invention has the following beneficial effects: 1. In the existing technology, most of the removal of arsenic, cadmium, and copper from phosphoric acid is carried out in concentrated acid storage tanks. Because concentrated phosphoric acid has high viscosity, the reagent is difficult to disperse, and the generated complexes need to be further removed, which increases the production cost. 2. This invention significantly improves the precipitation efficiency of arsenic, cadmium, and copper in wet-process phosphoric acid by adding a modifier and a heavy metal removal agent during the process of adding the phosphogypsum slurry into the filter, thereby forming a synergistic effect. This overcomes the problems of high toxicity of inorganic sulfides and long action time, low efficiency, and high cost of heavy metal removal agents in existing methods. 3. This invention employs a synergistic mechanism between modifiers and heavy metal removal agents, which can effectively reduce the amount of reagents used, accelerate the reaction time, significantly reduce production costs, and improve the economy and practicality of wet-process phosphoric acid. 4. The method of the present invention is simple to operate, requires no modification to existing processes and equipment, is easy to industrialize, and has good practical value and prospects for promotion and application; 5. The modifier of the present invention can effectively improve the dispersion performance of heavy metal removal agent in wet phosphoric acid, improve the solubility and stability of heavy metal removal agent, enhance the removal effect of arsenic, cadmium and copper, and solve the problems of easy sedimentation and deactivation of organic sulfides in the existing methods. Detailed Implementation

[0016] The technical solution of the present invention will be further described in detail below by listing some optional embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] Example 1: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0018] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid are mixed at a mass ratio of 1:1.3, and the mixture is slowly heated to 80°C under stirring and reacted for 30 minutes. After the reaction is completed, a certain amount of modifier and heavy metal removal agent are added before the slurry pump. The modifier and heavy metal removal agent are mixed and reacted with the slurry in the conveying pipeline. The slurry is then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue.

[0019] The modifier and heavy metal removal agent are added as follows: before the slurry pump, n-butanol is added as a co-solvent at a rate of 0.03% of the slurry mass; sodium stearate is added as an emulsifier at a rate of 0.015% of the slurry mass; a mixture of sodium stearate and sodium diisobutyl sulfosuccinate is added as an emulsifier at a molar ratio of 1:5 at a rate of 0.015% of the slurry mass; and zinc dialkyl dithiophosphate is added as a heavy metal removal agent at a rate of 1.5% of the slurry mass.

[0020] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0021] Purification: The crude concentrated phosphoric acid product was separated and purified by sedimentation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 1.25 ppm, arsenic concentration less than 3.14 ppm, and copper concentration less than 0.05 ppm.

[0022] Example 2: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0023] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid were mixed at a mass ratio of 1:1.34, and the mixture was slowly heated to 82°C with stirring for 45 minutes. After the reaction was completed, a certain amount of modifier and heavy metal removal agent were added before the slurry pump. The modifier and heavy metal removal agent were mixed and reacted with the slurry in the conveying pipeline. The slurry was then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue.

[0024] The modifier and heavy metal removal agent are added as follows: Isobutanol is added as a co-solvent before the slurry pump, and the amount added is 0.006% of the slurry mass; a mixture of calcium diisobutyl dithiophosphate, sodium diisooctyl sulfosuccinate and zinc dibutyl dithiophosphate is added as a heavy metal removal agent in a molar ratio of 1:2:6, and the amount added is 0.15% of the slurry mass.

[0025] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0026] Purification: The crude concentrated phosphoric acid product was separated and purified by sedimentation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 2.85 ppm, arsenic concentration less than 3.21 ppm, and copper concentration less than 0.09 ppm.

[0027] Example 3: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0028] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid were mixed at a mass ratio of 1:1.41, and the mixture was slowly heated to 85°C with stirring for 60 minutes. After the reaction was completed, a certain amount of modifier and heavy metal removal agent was added before the slurry pump. The modifier and heavy metal removal agent were mixed and reacted with the slurry in the conveying pipeline. The slurry was then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue. The modifier and heavy metal removal agent are added as follows: Before the slurry pump, a mixture of ethanol and n-butanol is added as a co-solvent at a mass ratio of 1:1, and the amount added is 0.002% of the slurry mass; a mixture of sodium ditridecyl sulfosuccinate, TX-10 and AEO-7 is added as an emulsifier at a molar ratio of 1:1:7, and the amount added is 0.017% of the slurry mass; a mixture of isooctyl dithiophosphate methyl ester and isopropyl dithiothiophosphate is added as a heavy metal removal agent at a mass ratio of 1:3, and the amount added is 1.2% of the slurry mass.

[0029] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0030] Purification: The crude concentrated phosphoric acid product was separated and purified by sedimentation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 2.89 ppm, arsenic concentration less than 2.55 ppm, and copper concentration less than 0.1 ppm.

[0031] Example 4: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0032] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid were mixed at a mass ratio of 1:1.5, and the mixture was slowly heated to 84°C under stirring for 35 minutes. After the reaction was completed, a certain amount of modifier and heavy metal removal agent were added before the slurry pump. The modifier and heavy metal removal agent were mixed and reacted with the slurry in the conveying pipeline. The slurry was then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue.

[0033] The modifier and heavy metal removal agent are added as follows: Propanol is added as a co-solvent before the slurry pump, with an addition amount of 0.01% of the slurry mass; a mixture of sodium dodecylbenzene sulfonate and sodium lignosulfonate is added as an emulsifier at a molar ratio of 1:2, with an addition amount of 0.02% of the slurry mass; a mixture of zinc diethyl dithiophosphite and dibutyl dithiophosphoric acid is added as a heavy metal removal agent at a mass ratio of 1:2.5, with an addition amount of 1.0% of the slurry mass.

[0034] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0035] Purification: The crude concentrated phosphoric acid product was separated and purified by sedimentation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 1.21 ppm, arsenic concentration less than 1.36 ppm, and copper concentration less than 0.03 ppm.

[0036] Example 5: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0037] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid were mixed at a mass ratio of 1:1.38, and the mixture was slowly heated to 87°C with stirring for 1.5 hours. After the reaction was completed, a certain amount of modifier and heavy metal removal agent were added before the slurry pump. The modifier and heavy metal removal agent were mixed and reacted with the slurry in the conveying pipeline. The slurry was then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue.

[0038] The modifier and heavy metal removal agent are added as follows: Before the slurry pump, a mixture of propanol and n-octanol is added at a ratio of 1:4 as a co-solvent, with an addition amount of 0.005% of the slurry mass; a mixture of sodium xylenesulfonate and polyethylene glycol is added at a molar ratio of 1:1 as an emulsifier, with an addition amount of 0.005% of the slurry mass; and a mixture of dioctadecyl magnesium thiophosphate and dihexyl dithiophosphate ethyl ester is added at a mass ratio of 1:2.3 as a heavy metal removal agent, with an addition amount of 1.15% of the slurry mass.

[0039] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0040] Purification: The crude concentrated phosphoric acid product was separated and purified by sedimentation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 0.25 ppm, arsenic concentration less than 3.65 ppm, and copper concentration less than 0.08 ppm.

[0041] Example 6: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0042] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid were mixed at a mass ratio of 1:1.47, and the mixture was slowly heated to 81°C under stirring for 1.2 hours. After the reaction was completed, a certain amount of modifier and heavy metal removal agent were added before the slurry pump. The modifier and heavy metal removal agent were mixed and reacted with the slurry in the conveying pipeline. The slurry was then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue.

[0043] The modifier and heavy metal removal agent are added as follows: Before the slurry pump, a mixture of isobutanol and isooctanol is added at a ratio of 1:1 as a co-solvent, with an addition amount of 0.002% of the slurry mass; a mixture of dioctyl sulfosuccinate, AEO-3, and polyethylene glycol is added at a molar ratio of 1:1:3 as an emulsifier, with an addition amount of 0.003% of the slurry mass; and a mixture of sodium dodecyl dithiophosphite and hexadecyl dithiophosphite is added at a mass ratio of 1:2.8 as a heavy metal removal agent, with an addition amount of 1.05% of the slurry mass.

[0044] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0045] Purification: The crude concentrated phosphoric acid product was purified by sedimentation and separation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 0.85 ppm, arsenic concentration less than 3.15 ppm, and copper concentration less than 0.1 ppm.

[0046] Example 7: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0047] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid were mixed at a mass ratio of 1:1.31, and the mixture was slowly heated to 83°C with stirring for 1 hour. After the reaction was completed, a certain amount of modifier and heavy metal removal agent were added before the slurry pump. The modifier and heavy metal removal agent were mixed and reacted with the slurry in the conveying pipeline. The slurry was then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue.

[0048] The modifier and heavy metal removal agent are added as follows: Before the slurry pump, a mixture of ethanol, butanol, and isooctanol is added in a 1:1:1 ratio as a co-solvent, with an addition amount of 0.003% of the slurry mass; a mixture of sodium secondary alkyl sulfonate, sodium dibutyl sulfosuccinate, and sodium lauryl phosphate is added in a 1:1:1 molar ratio as an emulsifier, with an addition amount of 0.0025% of the slurry mass; and a mixture of sodium dihexyl dithiophosphate and zinc dioctyl dithiophosphate is added in a 1:2.5 mass ratio as a heavy metal removal agent, with an addition amount of 1.08% of the slurry mass.

[0049] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0050] Purification: The crude concentrated phosphoric acid product was separated and purified by sedimentation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 0.77 ppm, arsenic concentration less than 2.68 ppm, and copper concentration less than 0.05 ppm.

[0051] Example 8: Phosphate ore pretreatment: Medium and low grade phosphate ore is used, and phosphate concentrate powder is obtained after crushing and flotation.

[0052] Acid hydrolysis reaction: Phosphate rock powder and 98% sulfuric acid were mixed at a mass ratio of 1:1.37, and the mixture was slowly heated to 82°C under stirring for 0.5 hours. After the reaction was completed, a certain amount of modifier and heavy metal removal agent was added before the slurry pump. The modifier and heavy metal removal agent were mixed and reacted with the slurry in the conveying pipeline. The slurry was then pumped to a plate and frame filter press for filtration to obtain dilute phosphoric acid and gypsum residue.

[0053] The modifier and heavy metal removal agent are added as follows: Before the slurry pump, a mixture of ethanol and butanol is added at a ratio of 1:2.5 as a co-solvent, and the amount added is 0.0015% of the slurry mass; a mixture of sodium sulfate lignosulfonate and benzalkonium chloride is added at a molar ratio of 1:6 as an emulsifier, and the amount added is 0.0034% of the slurry mass; a mixture of zinc butyryl octyl dithiophosphate and dioctyl dithiophosphoric acid is added at a mass ratio of 1:3.2 as a heavy metal removal agent, and the amount added is 1.25% of the slurry mass.

[0054] Sedimentation and concentration: Dilute phosphoric acid is settled in a settling tank to remove most of the suspended impurities, and then enters a triple-effect evaporator for concentration to obtain a crude concentrated phosphoric acid product with a P2O5 mass concentration of about 50%.

[0055] Purification: The crude concentrated phosphoric acid product was separated and purified by sedimentation to obtain pure wet-process phosphoric acid with residual cadmium concentration less than 0.67 ppm, arsenic concentration less than 1.58 ppm, and copper concentration less than 0.06 ppm.

[0056] It will be readily understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, substitutions, improvements, etc., made under the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A method for removing heavy metals from wet-process phosphoric acid, characterized in that Includes the following steps: (1) After crushing and pre-flotation treatment of phosphate rock, mix it with sulfuric acid at a mass ratio of 1:1.3-1.5 and react at 80-87℃ for 30-90 min to form a slurry; (2) Before the slurry enters the filter, add a modifier and a heavy metal removal agent to the slurry pump; add 1.5-15 kg of heavy metal removal agent per ton of slurry, with a mass ratio of modifier to heavy metal removal agent of 1:20-50; the reaction temperature of the modifier and heavy metal removal agent with the slurry is 70-80℃, and the reaction time is 5-30s; the modifier is a co-solvent and an emulsifier, the co-solvent is one or a mixture of two or more of ethanol, propanol, n-butanol, isobutanol, n-octanol, and isooctanol, and the emulsifier is one or a mixture of two or more of alkyl sulfonate, lignin sulfonate, sulfosuccinate, fatty alcohol polyoxyethylene ether, stearate, phosphate salt, and quaternary ammonium salt; the heavy metal removal agent is one or a mixture of two or more of dialkyl dithiophosphate, dialkyl dithiophosphate ester, dialkyl dithiophosphoric acid, and dialkyl dithiophosphite. (3) The slurry is filtered to obtain dilute phosphoric acid. The dilute phosphoric acid is then settled and concentrated to obtain crude concentrated phosphoric acid. The crude phosphoric acid is then settled, separated and purified to obtain pure wet phosphoric acid. The heavy metal residue in the obtained wet phosphoric acid is Cd≤3ppm, As≤4ppm and Cu≤0.1ppm.

2. The method for removing heavy metals from wet-process phosphoric acid according to claim 1, characterized in that: The emulsifier is an alkyl aromatic sulfonate.

3. The method for removing heavy metals from wet-process phosphoric acid according to claim 2, characterized in that: The alkyl aromatic sulfonates are sodium dodecylbenzenesulfonate, calcium dodecylbenzenesulfonate, sodium xylenesulfonate, or calcium xylenesulfonate; the alkyl sulfonates are sodium dodecylbenzenesulfonate or α-sulfofatty acid methyl ester; the lignin sulfonates are sodium lignin sulfonate; the sulfosuccinates are sodium dibutyl sulfosuccinate, sodium diisobutyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium diisooctyl sulfosuccinate, or sodium ditridecyl sulfosuccinate; the fatty alcohol polyoxyethylene ethers are AEO-3, AEO-7, or TX-10; the stearates are sodium stearate or calcium stearate; the phosphate esters are sodium lauryl phosphate; and the quaternary ammonium salts are didecyl dimethyl ammonium chloride or benzalkonium chloride.

4. The method for removing heavy metals from wet-process phosphoric acid according to claim 1, characterized in that: The amount of cosolvent added is 0.002-0.03% of the slurry mass, and the amount of emulsifier added is 0.003-0.02% of the slurry mass.

5. The method for removing heavy metals from wet-process phosphoric acid according to claim 2, characterized in that: The alkyl sulfonate is sodium secondary alkyl sulfonate.