阅读说明：本技术 一种制备单质砷的湿法处理工艺 (Wet processing technology for preparing simple substance arsenic ) 是由 田静 李晓恒 马立柱 王社古 彭国敏 郭引刚 杜主义 王夏 崔育涛 武岳彪 孙婷 于 2019-12-09 设计创作，主要内容包括：本申请公开一种制备单质砷的湿法处理工艺,属于冶金技术和环保技术领域,以含砷(As<Sup>5+</Sup>)溶液或冶炼废酸为原料,能将有色行业中含砷废水中的砷直接还原为单质砷,可减少含砷固废的量,将砷资源化,为有色冶炼行业含砷废水的工业化处理开辟了一条新途径。减少了硫化剂用量,大大缓解了冶炼企业钠盐富集的问题。采用常见的还原剂铝粉、镉粉等还原剂快速处理制约冶炼企业发展规模的有害元素砷,该方案具有广泛的社会效益及经济效益,值得在有色冶炼行业推广。(The application discloses a wet treatment process for preparing simple substance arsenic, which belongs to the technical field of metallurgy and environmental protection and comprises arsenic (As) 5+ ) The solution or the smelting waste acid is used as a raw material, arsenic in arsenic-containing waste water in the nonferrous industry can be directly reduced into simple substance arsenic, the amount of arsenic-containing solid waste can be reduced, the arsenic is recycled, and a new way is opened up for the industrial treatment of the arsenic-containing waste water in the nonferrous smelting industry. Reduces the dosage of vulcanizing agent and greatly relieves the problem of sodium salt enrichment of smelting enterprises. The method adopts common reducing agents such as aluminum powder and cadmium powder to rapidly treat harmful element arsenic which restricts the development scale of smelting enterprises, has wide social and economic benefits, and is worth popularizing in the non-ferrous smelting industry.)

1. A wet processing technology for preparing simple substance arsenic by taking arsenic-containing solution as raw material is characterized by comprising the following steps:

the method comprises the following steps: taking an arsenic-containing solution containing 0.2-60 g/L of arsenic as a raw material, detecting and analyzing the content of pentavalent arsenic, adding a reducing agent A into the solution for reduction, wherein the using amount of the reducing agent A is 1.5-3 times of the molar theoretical consumption of the pentavalent arsenic in the solution, and after reducing for 0.5-6 hours, finishing the reaction;

step two: adjusting the acidity of the liquid obtained in the step one by using sulfuric acid, and controlling the concentration of the sulfuric acid in the solution to be 10-250 g/L;

step three: heating the solution obtained in the step two to 40-95 ℃, adding a reducing agent B according to the molar ratio of arsenic to the reducing agent B of 1 (1.5-4) in the liquid, and continuing to react for 1-5 h after the addition is finished;

step four: and D, carrying out solid-liquid separation on the reacted liquid obtained in the step three to obtain filtered solution and solid, drying and dehydrating the solid to obtain simple substance arsenic, and feeding the filtered liquid into a subsequent wastewater treatment process to recover other elements.

2. The wet processing method for preparing elemental arsenic from an arsenic-containing solution as claimed in claim 1, wherein the reducing agent A in the first step is one or a mixture of two or more of sulfur dioxide, sodium sulfite, sodium metabisulfite, sodium thiosulfate, etc. in any ratio.

3. The wet processing process for preparing elemental arsenic from arsenic-containing solution as claimed in claim 1, wherein the reducing agent B in step three is one or a mixture of more than two of aluminum powder and cadmium powder in any proportion.

4. The wet processing process for preparing elemental arsenic from an arsenic-containing solution as claimed in claim 1, wherein the arsenic-containing solution in the first step contains 1-30 g/L arsenic.

5. The wet processing process for preparing elemental arsenic from an arsenic-containing solution as claimed in claim 1, wherein the concentration of sulfuric acid in the second step is 50-150 g/L.

6. The wet processing process for preparing elemental arsenic from an arsenic-containing solution as claimed in claim 1, wherein the heating temperature in step three is not less than 60 ℃.

7. A wet processing technology for preparing simple substance arsenic by taking smelting waste acid as a raw material is characterized by comprising the following steps:

(1) copper deposition by vulcanization; adding arsenic sulfide into the solution by taking smelting waste acid as a raw material, wherein the using amount of the arsenic sulfide is 0.4-1.5 times of the molar weight of copper ions in the solution, heating to 50-100 ℃, reacting for 1-4 hours, performing solid-liquid separation to obtain copper precipitation liquid and copper sulfide slag, and adding the copper sulfide slag serving as copper concentrate into a pyrometallurgical copper smelting system;

(2) reduction and arsenic precipitation: placing the copper-deposited solution obtained in the step (1) at 40-95 ℃ for heat preservation, adding a reducing agent according to the dosage of 0.9-1.8 times of the molar weight of arsenic, continuing to react for 1-5 h after the addition is finished, and performing solid-liquid separation to obtain a reduced solution and simple substance arsenic;

(3) and (4) sulfurizing and depositing arsenic: adding a vulcanizing agent into the reduced liquid obtained in the step (2), wherein the consumption of the vulcanizing agent is 1.1-1.8 times of the theoretical consumption of arsenic in the waste acid, the reaction time is 10-120 min, and performing solid-liquid separation to obtain arsenic sulfide and an arsenic precipitation liquid; and (3) returning the arsenic sulfide to the step (1) for copper sulfide precipitation, and allowing the arsenic-precipitated liquid to enter a water treatment process.

8. The wet processing process for preparing elemental arsenic from waste smelting acid as a raw material according to claim 7, wherein the reducing agent in the step (2) is one or a mixture of more than two of aluminum powder, iron powder and zinc powder in any proportion.

9. The wet processing process for preparing elemental arsenic from smelting waste acid as a raw material according to claim 7, wherein the vulcanizing agent in the step (3) is one or a mixture of more than two of sodium sulfide, sodium hydrosulfide and ferrous sulfide in any proportion.

Technical Field

The invention belongs to the field of metallurgical technology and environmental protection, and particularly relates to a wet treatment process for preparing elemental arsenic.

Background

The raw materials of the nonferrous smelting industry are mainly sulfide concentrates, the sulfide concentrates have higher and higher impurities along with the shortage of the raw material market, particularly the arsenic content is more and more, the arsenic mainly exists in the sulfide concentrates in the form of sulfides and oxides, and in the pyrometallurgical process, the arsenic mainly volatilizes into smelting flue gas in the form of oxides, and part of the arsenic enters into a slag phase. In the dust collection process of the flue gas, part of arsenic can be directly condensed to produce arsenic trioxide, the rest arsenic is washed in the acid preparation process and enters waste acid, and the waste acid is vulcanized to produce arsenic sulfide slag which is then treated by a unit with treatment quality.

With the continuous expansion of nonferrous smelting scale, arsenic-containing solid waste in China is more and more at present, and the treatment of the arsenic-containing solid waste can be divided into the traditional pyrogenic treatment and wet treatment processes. The pyrogenic process treatment process is characterized in that arsenic is separated and recovered in the form of white arsenic by utilizing the characteristic that arsenide is volatile at high temperature, but the process has serious environmental pollution and severe production environment; the wet treatment process generally comprises the steps of selectively leaching arsenic-containing solid waste to remove arsenic, and then recycling or harmlessly treating the arsenic, wherein the process can generate a large amount of solid waste, is high in treatment cost and is not beneficial to environmental protection. With the increasing environmental protection situation, the nonferrous smelting industry explores to convert arsenic in arsenic-containing solid waste into white arsenic and further convert the white arsenic into simple substance arsenic so as to realize reduction and harmlessness, which is a necessary way for the development of the industry in the future.

Chinese patent 201310310187.0 discloses a method for recovering simple substance arsenic from arsenic sulfide slag, which comprises dissolving arsenic in arsenic sulfide by alkaline oxidation, adding concentrated hydrochloric acid and stannous chloride powder, reacting for 8h, separating solid and liquid to obtain black solid simple substance arsenic, and recovering stannous chloride from the solution by electrolysis. The process has long flow and high cost. Chinese patent 201810798135.5 discloses a process for obtaining simple substance arsenic by reduction of arsenic trioxide, which comprises mixing arsenic trioxide, low-melting-point substance, reducing agent and soda ash uniformly, placing into a crucible for heat preservation reaction to obtain low-melting-point and difficult-to-volatilize arsenic alloy, and recovering arsenic alloy in vacuum to obtain metallic arsenic. The invention provides a wet processing technology for rapidly preparing simple substance arsenic aiming at arsenic-containing liquid in the nonferrous smelting industry.

Disclosure of Invention

Aiming at the current situations of great environmental pollution and high cost of reducing white arsenic into elemental arsenic by pyrogenic process in the nonferrous industry, the invention provides a simple and convenient wet-process treatment process for the elemental arsenic with high recovery rate and good environmental benefit ⁵⁺) Solutions ofOne uses waste smelting acid as raw material.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a wet processing technology for preparing simple substance arsenic by taking arsenic-containing solution as raw material comprises the following steps:

the method comprises the following steps: taking an arsenic-containing solution (containing As0.2-60 g/L) as a raw material, detecting and analyzing the content of pentavalent arsenic, adding a reducing agent A into the solution for reduction, wherein the using amount of the reducing agent A is 1.5-3 times of the molar theoretical consumption of the pentavalent arsenic in the solution, and after 0.5-6 h of reduction, finishing the reaction and realizing the reaction principle:

As ⁵⁺+2e→As ³⁺；

step two: adjusting the acidity of the liquid obtained in the step one by using sulfuric acid, and controlling the concentration of the sulfuric acid in the solution to be 10-250 g/L;

step three: heating the solution obtained in the second step to 40-95 ℃, adding a reducing agent B according to the molar ratio 1 (1.5-4) of arsenic to the reducing agent B in the liquid, and continuing to react for 1-5 h after the addition, wherein the reaction principle is as follows:

2AsO ₃ ^3-+3Cd+12H ⁺→2As+3Cd ²⁺+6H ₂O；

AsO ₃ ^3-+Al+6H ⁺→As+Al ³⁺+3H ₂O；

step four: and D, carrying out solid-liquid separation on the reacted liquid obtained in the step three to obtain filtered solution and solid, drying and dehydrating the solid to obtain simple substance arsenic, and feeding the filtered liquid into a subsequent wastewater treatment process to recover other elements.

The reducing agent A in the step one is one or a mixture of more than two of sulfur dioxide, sodium sulfite, sodium metabisulfite and sodium thiosulfate in any proportion.

The reducing agent B in the third step is one or a mixture of more than two of aluminum powder and cadmium powder in any proportion.

Preferably, the arsenic-containing solution in the first step contains 1-30 g/L of arsenic, the concentration of sulfuric acid in the second step is 50-150 g/L, and the heating temperature in the third step is not less than 60 ℃.

A wet treatment process for preparing simple substance arsenic by taking smelting waste acid as a raw material comprises the following steps:

(1) copper deposition by vulcanization; taking smelting waste acid (the content of sulfuric acid in the waste acid is 30-150 g/L) as a raw material, adding arsenic sulfide into the solution, wherein the using amount of the arsenic sulfide is 0.4-1.5 times of the molar amount of copper ions in the solution, heating to 50-100 ℃, reacting for 1-4 hours, carrying out solid-liquid separation to obtain copper precipitation liquid and copper sulfide slag, and taking the copper sulfide slag as copper concentrate to be added into a pyrometallurgical copper smelting system; step (1) is not essential, when Cu is contained in the waste acid ²⁺Step (1) is only required when the concentration is more than 0.5g/L, if Cu in waste acid ²⁺The concentration is less than or equal to 0.5g/L, and the reduction and arsenic precipitation in the step (2) are directly carried out;

(2) reduction and arsenic precipitation: placing the copper-deposited solution obtained in the step (1) at 40-95 ℃ for heat preservation, adding a reducing agent according to the dosage of 0.9-1.8 times of the molar weight of arsenic, continuing to react for 1-5 h after the addition is finished, and performing solid-liquid separation to obtain a reduced solution and simple substance arsenic;

(3) and (4) sulfurizing and depositing arsenic: adding a vulcanizing agent into the reduced liquid obtained in the step (2), wherein the consumption of the vulcanizing agent is 1.1-1.8 times of the theoretical consumption of arsenic in the waste acid, the reaction time is 10-120 min, and performing solid-liquid separation to obtain arsenic sulfide and an arsenic precipitation liquid; and (3) returning the arsenic sulfide to the step (1) for copper sulfide precipitation, and allowing the arsenic-precipitated liquid to enter a water treatment process.

Further, the reducing agent in the step (2) is one or a mixture of more than two of aluminum powder, iron powder and zinc powder in any proportion.

Further, the vulcanizing agent in the step (3) is one or a mixture of more than two of sodium sulfide, sodium hydrosulfide and ferrous sulfide in any proportion.

The invention has the beneficial effects that: the wet treatment process for preparing the elemental arsenic can directly reduce the arsenic in the arsenic-containing wastewater in the nonferrous industry into the elemental arsenic, can reduce the amount of arsenic-containing solid waste, recycles the arsenic, and opens up a new way for the industrialized treatment of the arsenic-containing wastewater in the nonferrous smelting industry. Reduces the dosage of vulcanizing agent and greatly relieves the problem of sodium salt enrichment of smelting enterprises.

The method adopts common reducing agents such as aluminum powder and cadmium powder to rapidly treat harmful element arsenic which restricts the development scale of smelting enterprises, has wide social and economic benefits, and is worth popularizing in the non-ferrous smelting industry.

Drawings

FIG. 1 is a flow diagram of the process of the present invention using an arsenic-containing solution as a feedstock;

FIG. 2 is a process flow diagram of the invention using waste smelting acid as raw material.

Detailed Description

In order to make the production process and technical effects of the present invention known in detail to those skilled in the art, the technical solutions and technical effects of the present invention are further described below with specific examples.