阅读说明：本技术 一种铜电解液脱铜脱砷的方法 (Method for removing copper and arsenic from copper electrolyte ) 是由 魏栋 董广刚 刘士祥 于 2021-07-09 设计创作，主要内容包括：本发明提供一种铜电解液脱铜脱砷的方法,包括以下步骤：将待处理电解液进行多效蒸发和强冷结晶,得到铜盐结晶和结晶母液；将所述结晶母液中五价砷还原,冷却结晶,真空抽滤,得到铜砷结晶物；将铜砷结晶物进行酸洗和过滤,得到粗三氧化二砷和硫酸铜溶液。上述工艺简单,容易控制与操作,解决了诱导法脱铜脱砷电耗高的问题,大幅降低脱铜脱砷的能耗；铜和砷的脱除率较高；不产生含铜中间物料,能够降低处理成本,也避免了含铜物料返炉的影响,不会降低铜精矿的处理量；该工艺不产生剧毒的砷化氢气体,有效降低工作人员的职业健康风险；脱铜脱砷过程中,铜砷能够分别转化为高纯铜粉和三氧化二砷,不产生任何废液和含铜物料,工艺安全环保。(The invention provides a method for removing copper and arsenic from copper electrolyte, which comprises the following steps: carrying out multi-effect evaporation and forced cooling crystallization on the electrolyte to be treated to obtain copper salt crystals and crystallization mother liquor; reducing pentavalent arsenic in the crystallization mother liquor, cooling, crystallizing and carrying out vacuum filtration to obtain a copper-arsenic crystal; and (3) carrying out acid washing and filtering on the copper-arsenic crystal to obtain crude arsenic trioxide and copper sulfate solution. The process is simple and easy to control and operate, solves the problem of high power consumption in copper and arsenic removal by an induction method, and greatly reduces the energy consumption for copper and arsenic removal; the removal rate of copper and arsenic is high; copper-containing intermediate materials are not generated, so that the treatment cost can be reduced, the influence of returning the copper-containing materials to the furnace is avoided, and the treatment capacity of copper concentrate is not reduced; the process does not generate highly toxic arsine gas, and effectively reduces occupational health risks of workers; in the copper and arsenic removing process, copper and arsenic can be respectively converted into high-purity copper powder and arsenic trioxide, no waste liquid and copper-containing materials are generated, and the process is safe and environment-friendly.)

1. A method for removing copper and arsenic from copper electrolyte comprises the following steps:

carrying out multi-effect evaporation and forced cooling crystallization on the electrolyte to be treated to obtain copper salt crystals and crystallization mother liquor;

reducing pentavalent arsenic in the crystallization mother liquor, cooling, crystallizing and carrying out vacuum filtration to obtain a copper-arsenic crystal;

and (3) carrying out acid washing and filtering on the copper-arsenic crystal to obtain crude arsenic trioxide and copper sulfate solution.

2. The method of claim 1, wherein the multi-effect evaporation is two-effect evaporation or three-effect evaporation;

the temperature of the first-effect evaporation is 110-120 ℃;

the vacuum degree of final effect evaporation is 10-20 KPa;

the judgment of the end point of the multi-effect evaporation is based on the fact that the density of the evaporated solution is 1.35-1.65 g/cm³。

3. The method according to claim 1, wherein the temperature of the forced cooling crystallization is-5 ℃ to 5 ℃.

4. The method according to claim 1, wherein the reducing agent used for the reduction is selected from one or more of calcium hydrogen sulfite, calcium sulfite, sodium hydrogen sulfite, and sodium sulfite.

5. The method according to claim 1, wherein the temperature of the reduction is 30 to 70 ℃,

the reduction time is 2-3 h;

the reduction is carried out under the stirring condition, and the stirring speed is 300-450 rpm.

6. The method according to claim 1, wherein the temperature of the cooling crystallization is-15 ℃ to-5 ℃.

7. The method of claim 1, wherein the crude arsenic trioxide is acid washed and dried to obtain high purity arsenic trioxide;

the pickling temperature is 20-30 ℃, and the pickling time is 5-10 min.

Technical Field

The invention belongs to the technical field of electrolyte, and particularly relates to a method for removing copper and arsenic from copper electrolyte.

Background

During the copper electrolysis process, copper, arsenic impurity and the like in the anode plate can be continuously dissolved out, and part of the copper and the arsenic impurity enter the electrolyte. The continuous enrichment of copper and arsenic impurities in the electrolyte can influence the smooth operation of the electrolytic process. In order to ensure the stability of an electrolyte system, the electrolyte needs to be subjected to copper removal and arsenic removal.

At present, electrolytic workshops in the same industry generally adopt an induction method to remove copper and arsenic. However, the induction method for copper and arsenic removal has the following disadvantages: (1) the power consumption is high; (2) a large amount of copper-containing intermediate materials can be generated, and the treatment cost is increased; (3) in the later stage of dearsenization, extremely toxic arsine gas can be generated, and certain risk is brought to staff occupational health. (4) When the content of arsenic impurity in the copper anode plate is high, the arsenic removal and the copper removal of the electrolyte cannot be balanced.

Disclosure of Invention

In view of the above, the present invention is directed to a method for removing copper and arsenic from a copper electrolyte, which is simple and has high removal rates of copper and arsenic.

The invention provides a method for removing copper and arsenic from copper electrolyte, which comprises the following steps:

carrying out multi-effect evaporation and forced cooling crystallization on the electrolyte to be treated to obtain copper salt crystals and crystallization mother liquor;

reducing pentavalent arsenic in the crystallization mother liquor, cooling, crystallizing and carrying out vacuum filtration to obtain a copper-arsenic crystal;

and (3) carrying out acid washing and filtering on the copper-arsenic crystal to obtain crude arsenic trioxide and copper sulfate solution.

Preferably, the multi-effect evaporation adopts two-effect evaporation or three-effect evaporation;

the temperature of the first-effect evaporation is 110-120 ℃;

the vacuum degree of final effect evaporation is 10-20 KPa;

the judgment of the end point of the multi-effect evaporation is based on the fact that the density of the evaporated solution is 1.35-1.65 g/cm³。

Preferably, the temperature of the forced cooling crystallization is-5 ℃ to 5 ℃.

Preferably, the reducing agent used for the reduction is selected from one or more of calcium hydrogen sulfite, calcium sulfite, sodium hydrogen sulfite and sodium sulfite.

Preferably, the reduction temperature is 30-70 ℃, and the reduction time is 2-3 h;

the reduction is carried out under the stirring condition, and the stirring speed is 300-450 rpm.

Preferably, the temperature of the cooling crystallization is-15 ℃ to-5 ℃.

Preferably, the crude arsenic trioxide is subjected to acid washing and drying to obtain high-purity arsenic trioxide;

the pickling temperature is 20-30 ℃, and the pickling time is 5-10 min.

The invention provides a method for removing copper and arsenic from copper electrolyte, which comprises the following steps: carrying out multi-effect evaporation and forced cooling crystallization on the electrolyte to be treated to obtain copper salt crystals and crystallization mother liquor; reducing pentavalent arsenic in the crystallization mother liquor, cooling, crystallizing and carrying out vacuum filtration to obtain a copper-arsenic crystal; and (3) carrying out acid washing and filtering on the copper-arsenic crystal to obtain crude arsenic trioxide and copper sulfate solution. The process provided by the invention is simple and easy to control and operate, solves the problem of high power consumption in copper and arsenic removal by an induction method, and greatly reduces the energy consumption in copper and arsenic removal; the removal rate of copper and arsenic is high; the process does not produce copper-containing intermediate materials, can reduce the treatment cost of the copper-containing materials, also avoids the influence of the copper-containing materials returning to the furnace, and does not reduce the treatment capacity of copper concentrate; the process does not generate highly toxic arsine gas, can avoid personnel from contacting the highly toxic arsine gas, and effectively reduces the occupational health risk of the personnel; in the process of high-arsenic copper anode electrolysis, the problem that the balance between dearsenization and decopperization is easy to occur during the purification of the electrolyte, so that the production of copper electrolysis is restricted, and the method can solve the problem; in the copper and arsenic removing process, copper and arsenic can be respectively converted into high-purity copper powder and arsenic trioxide, no waste liquid and copper-containing materials are generated, and the process is safe and environment-friendly.

Drawings

FIG. 1 is a process flow diagram for copper removal and arsenic removal of copper electrolyte provided by the invention.

Detailed Description

The invention provides a method for removing copper and arsenic from copper electrolyte, which comprises the following steps:

carrying out multi-effect evaporation and forced cooling crystallization on the electrolyte to be treated to obtain copper salt crystals and crystallization mother liquor;

reducing pentavalent arsenic in the crystallization mother liquor, cooling, crystallizing and carrying out vacuum filtration to obtain a copper-arsenic crystal;

and (3) carrying out acid washing and filtering on the copper-arsenic crystal to obtain crude arsenic trioxide and copper sulfate solution.

The process provided by the invention is simple and easy to control and operate, solves the problem of high power consumption in copper and arsenic removal by an induction method, and greatly reduces the energy consumption in copper and arsenic removal; the removal rate of copper and arsenic is high; the process does not produce copper-containing intermediate materials, can reduce the treatment cost of the copper-containing materials, also avoids the influence of the copper-containing materials returning to the furnace, and does not reduce the treatment capacity of copper concentrate; the process does not generate highly toxic arsine gas, can avoid personnel from contacting the highly toxic arsine gas, and effectively reduces the occupational health risk of the personnel; in the process of high-arsenic copper anode electrolysis, the problem that the balance between dearsenization and decopperization is easy to occur during the purification of the electrolyte, so that the production of copper electrolysis is restricted, and the method can solve the problem; in the copper and arsenic removing process, copper and arsenic can be respectively converted into high-purity copper powder and arsenic trioxide, no waste liquid and copper-containing materials are generated, and the process is safe and environment-friendly.

The method carries out multi-effect evaporation and forced cooling crystallization on the electrolyte to be treated to obtain copper salt crystals and crystallization mother liquor. In the invention, the content of Cu in the electrolyte to be treated is 35-60 g/L, the content of As is 5-15 g/L, and H is₂SO₄The content is 150-220 g/L. The invention adopts multi-effect evaporation, has high efficiency and high energy utilization rate; in addition, arsenic in the electrolyte can be directly reduced after being enriched, evaporation amount in the subsequent arsenic preparation is reduced, and energy consumption is saved. The solution after multi-effect evaporation is subjected to strong cooling crystallization, so that the copper enriched in the electrolyte can be removed, and the redundant copper in the electrolytic system is converted into copper salt crystals with low impurities; the low-impurity copper salt is favorable for preparing high-purity copper powderCan be re-dissolved and then returns to an electrolysis system to balance copper ions, so that the adjustable space for copper electrolysis is enlarged. In the present invention, the multiple-effect evaporation may adopt two-effect evaporation or three-effect evaporation; the temperature of the first-effect evaporation is 110-120 ℃, and the vacuum degree of the last-effect evaporation is 10-20 KPa; the judgment of the end point of the multi-effect evaporation is based on the fact that the density of the evaporated solution is 1.35-1.65 g/cm³. The temperature of the strong cooling crystallization is-5 ℃ to 5 ℃. The impurities such as zinc, iron, arsenic, antimony, bismuth and the like in the copper salt crystal obtained by the strong cooling crystallization are very low, and high-density electrodeposition can be carried out to obtain high-purity copper powder; or returning to an electrolysis system after re-dissolution to balance copper ions, so that the adjustable space for copper electrolysis is enlarged.

After obtaining the crystallization mother liquor, the method reduces pentavalent arsenic in the crystallization mother liquor, cools and crystallizes the pentavalent arsenic, and carries out vacuum filtration to obtain the copper-arsenic crystal. In the present invention, the reducing agent used for the reduction is selected from one or more of calcium hydrogen sulfite, calcium sulfite, sodium hydrogen sulfite and sodium sulfite. The reduction temperature is 30-70 ℃, and the reduction time is 2-3 h; the reduction is carried out under the stirring condition, and the stirring speed is 300-450 rpm. The temperature of the cooling crystallization is-15 ℃ to-5 ℃. The reducing agent calcium hydrogen sulfite can fully reduce pentavalent arsenic in the crystallization mother liquor into trivalent arsenic, and other impurity elements are not introduced during reduction; compared with sodium sulfite and sodium bisulfite, impurity elements such as sodium and the like cannot be introduced into an electrolysis system when calcium bisulfite is reduced; and calcium sulfate generated by the reduction reaction of the calcium hydrogen sulfite can adsorb part of impurities in the electrolyte, so that the impurity amount in the electrolyte can be reduced.

After vacuum filtration, not only obtaining copper arsenic crystal but also obtaining secondary crystallization mother liquor; the secondary crystallization mother liquor can be returned to an electrolysis system to balance the volume of the electrolyte.

The invention carries out acid washing and filtration on the copper arsenic crystal to obtain crude arsenic trioxide and copper sulfate solution. The acid adopted for pickling the copper arsenic crystal is dilute sulfuric acid solution or demineralized water, and the purpose of pickling is to separate arsenic trioxide from the copper arsenic crystal. The obtained copper sulfate solution is preferably returned to the electrolysis system together with the secondary crystallization mother liquor obtained in the previous process.

The invention continuously performs acid cleaning and drying on the crude arsenic trioxide. After acid washing, carrying out solid-liquid separation to obtain a product arsenic trioxide and an acid washing solution; the pickling solution is recycled, and after the impurity concentration in the pickling solution is enriched, the pickling solution is preferably returned to the pickling process of the copper-arsenic crystal for reuse, so that the generation of waste liquid is avoided. The crude arsenic trioxide is preferably subjected to acid washing by using sulfuric acid; the pickling temperature is 20-30 ℃, and the pickling time is 5-10 min. The mass concentration of the sulfuric acid is 5-10%; in specific embodiments, the mass concentration of the sulfuric acid is 6%, 8%, or 9%. The purity of the obtained arsenic trioxide conforms to the GB-26721-2011 arsenic trioxide-national standard. The purity of the arsenic trioxide is as high as 99.8%.

In order to further illustrate the present invention, the method for copper electrolytic copper removal and arsenic removal provided by the present invention is described in detail below with reference to the examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Take 10m³The electrolyte containing 45g/L copper and 9.5g/L arsenic adopts double-effect evaporation, the temperature of the first effect is controlled to be 110 ℃, and the vacuum degree of the second effect is controlled to be 15 kpa. When the density of the electrolyte reaches 1.45g/cm³When the evaporation is finished, forced cooling crystallization is carried out, and the cooling water temperature of a forced cooling unit is controlled at-5 ℃. After cooling, 1032kg of copper salt crystals and 5.2m of the crystals were obtained by filtration³Crystallizing the mother liquor. The mother liquor contains 39.7g/L of copper and 18.2g/L of arsenic.

Mixing 5.2m³The crystallization mother liquor is placed in a reduction tank, 129.2kg of calcium hydrogen sulfite is added into the crystallization mother liquor, the reduction temperature is controlled at 40 ℃, the reduction time is controlled at 2.5 hours, and the stirring speed is controlled at 350 r/min. After the reaction is finished, cooling and crystallizing the reduced liquid.

When the liquid is cooled and crystallized after reduction, the temperature of the cooling water is controlled at-10 ℃. After crystallization, 540kg of copper arsenic crystals and a crystallization mother liquor were obtained.

And (3) rapidly pickling the copper-arsenic crystal to obtain a primary crystal arsenic trioxide and copper sulfate solution. And returning the crystallization mother liquor and the copper sulfate solution to an electrolysis system, and carrying out acid washing on the arsenic trioxide obtained by primary crystallization. Controlling the pickling temperature to be 24 ℃ and the sulfuric acid concentration to be 6%, and drying the obtained arsenic trioxide after pickling to obtain 100.8kg of white powdery product arsenic trioxide. The purity of the obtained arsenic trioxide conforms to the GB-26721-2011 arsenic trioxide-national standard.

In the whole process, the removal rate of copper in the electrolyte is 53.6 percent, and the removal rate of arsenic is 80.4 percent.

Example 2

Take 15m³The electrolyte containing 47g/L of copper and 10g/L of arsenic adopts double-effect evaporation, the temperature of the first effect is controlled to be 113 ℃, and the vacuum degree of the second effect is controlled to be 13 kpa. When the density of the electrolyte reaches 1.5g/cm³When the evaporation is finished, forced cooling crystallization is carried out, and the cooling water temperature of a forced cooling unit is controlled at-3 ℃. After cooling, 1615kg of copper salt crystals and 7.8m are obtained by filtration³Crystallizing the mother liquor. The mother liquor contains 41.8g/L of copper and 19.1/L of arsenic.

Will be 7.8m³And (3) placing the crystallization mother liquor in a reduction tank, adding 204kg of calcium hydrogen sulfite into the crystallization mother liquor, controlling the reduction temperature to be 45 ℃, the reduction time to be 2.5 hours and the stirring speed to be 350 r/min. After the reaction is finished, cooling and crystallizing the reduced liquid.

When the liquid is cooled and crystallized after reduction, the temperature of the cooling water is controlled at-8 ℃. After the crystallization, 852kg of copper arsenic crystals and a mother solution for crystallization were obtained.

And (3) rapidly pickling the copper-arsenic crystal to obtain a primary crystal arsenic trioxide and copper sulfate solution. And returning the crystallization mother liquor and the copper sulfate solution to an electrolysis system, carrying out acid washing on the arsenic trioxide obtained by primary crystallization, controlling the acid washing temperature to be 28 ℃ and the sulfuric acid concentration to be 9%, and drying the arsenic trioxide obtained after acid washing to obtain 163kg of white powdery product arsenic trioxide. The purity of the obtained arsenic trioxide conforms to the GB-26721-2011 arsenic trioxide-national standard.

In the whole process, the removal rate of copper in the electrolyte is 53.8 percent, and the removal rate of arsenic is 82.3 percent.

Example 3

Take 20m³The electrolyte containing 43g/L copper and 11g/L arsenic adopts double-effect evaporation, the temperature of the first effect is controlled to be 110 ℃, and the vacuum degree of the second effect is controlled to be 17 kpa. When in useThe density of the electrolyte reaches 1.55g/cm³When the evaporation is finished, forced cooling crystallization is carried out, and the cooling water temperature of a forced cooling unit is controlled at-7 ℃. After cooling, filtration was carried out to obtain 1960kg of copper salt crystals and 11.2m³Crystallizing the mother liquor. The mother liquid contains 35.5g/L of copper and 19.5g/L of arsenic.

Mix 11.2m³The crystallization mother liquor is placed in a reduction tank, 299kg of calcium hydrogen sulfite is added into the crystallization mother liquor, the reduction temperature is controlled to be 45 ℃, the reduction time is controlled to be 2.5 hours, and the stirring speed is 350 r/min. After the reaction is finished, cooling and crystallizing the reduced liquid.

When the liquid is cooled and crystallized after reduction, the temperature of the cooling water is controlled at-12 ℃. After crystallization, 1063kg of copper arsenic crystals and a crystallization mother liquor were obtained.

And (3) rapidly pickling the copper-arsenic crystal to obtain a primary crystal arsenic trioxide and copper sulfate solution. And returning the crystallization mother liquor and the copper sulfate solution to an electrolysis system, carrying out acid washing on the arsenic trioxide obtained by primary crystallization, controlling the acid washing temperature to be 26 ℃ and the sulfuric acid concentration to be 8%, and drying the arsenic trioxide obtained after acid washing to obtain 245.7kg of a white powdery product arsenic trioxide. The purity of the obtained arsenic trioxide conforms to the GB-26721-2011 arsenic trioxide-national standard.

In the whole process, the removal rate of copper in the electrolyte is 54 percent, and the removal rate of arsenic is 84.6 percent.

From the above embodiments, the present invention provides a method for removing copper and arsenic from a copper electrolyte, comprising the following steps: carrying out multi-effect evaporation and forced cooling crystallization on the electrolyte to be treated to obtain copper salt crystals and crystallization mother liquor; reducing pentavalent arsenic in the crystallization mother liquor, cooling, crystallizing and carrying out vacuum filtration to obtain a copper-arsenic crystal; and (3) carrying out acid washing and filtering on the copper-arsenic crystal to obtain crude arsenic trioxide and copper sulfate solution. The process provided by the invention is simple and easy to control and operate, solves the problem of high power consumption in copper and arsenic removal by an induction method, and greatly reduces the energy consumption in copper and arsenic removal; the removal rate of copper and arsenic is high; the process does not produce copper-containing intermediate materials, can reduce the treatment cost of the copper-containing materials, also avoids the influence of the copper-containing materials returning to the furnace, and does not reduce the treatment capacity of copper concentrate; the process does not generate highly toxic arsine gas, can avoid personnel from contacting the highly toxic arsine gas, and effectively reduces the occupational health risk of the personnel; in the process of high-arsenic copper anode electrolysis, the problem that the balance between dearsenization and decopperization is easy to occur during the purification of the electrolyte, so that the production of copper electrolysis is restricted, and the method can solve the problem; in the copper and arsenic removing process, copper and arsenic can be respectively converted into high-purity copper powder and arsenic trioxide, no waste liquid and copper-containing materials are generated, and the process is safe and environment-friendly.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.