Method for separating and enriching indium from high-arsenic leaching solution containing zinc and indium

Abstract

The invention discloses a method for separating and enriching indium from zinc-containing and indium-containing high-arsenic leaching liquid, which comprises the following steps: adding lime into the leaching liquid containing 0.5-2.0 g / L of indium, 5-15 g / L of arsenic, 10-40 g / L of sulfuric acid and 100-150 g / L of zinc, stirring, neutralizing, precipitating, enabling the pH value to be 1.6-1.8, carrying out liquid-solid separation to obtain indium-rich gypsum slag and indium-poor liquid, and taking the indium-rich gypsum slag as an enrichment for recovering indium. According to the method, after neutralization and precipitation, the content of residual indium in the indium-poor liquid is only 10-20 mg / L, the precipitation rate of indium is not smaller than 98%, and efficient separation and enrichment of indium are achieved. According to the method, harmful arsenic hydride gas cannot be generated in the neutralization process, operation is easy and convenient, implementation is easy, and the problem of separation and enrichment of indium from the high-arsenic indium-containing solution is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for separating and enriching indium from a zinc-containing, indium-containing and high-arsenic leaching solution. Background Art

[0002] The iron alum slag and high acid leaching slag produced by hydrometallurgy are hazardous solid wastes and must be treated harmlessly according to environmental protection requirements. When smelting-reduction fuming treatment is used to comprehensively recover zinc and lead in the slag, the valuable element indium and impurity element arsenic in the slag also volatilize and enrich in the zinc oxide fume. The arsenic in the zinc oxide fume brings great difficulties to the subsequent wet treatment and recovery of indium.

[0003] Sulfuric acid system leaching treatment of zinc oxide dust is the most commonly used method in industry. In order to improve the recovery rate of indium, it is necessary to use an acid leaching method to increase the leaching rate of indium as much as possible to reduce the loss of indium in the leaching residue.

[0004] In the production of hydrometallurgical zinc, two methods, namely, metal zinc powder replacement and neutralization hydrolysis, are usually used to enrich indium from the acidic indium-containing leachate. However, for high-arsenic zinc oxide dust, a considerable concentration of arsenic is inevitably present in the indium-containing leachate obtained by acidic leaching. For this acidic arsenic-containing and indium-containing leachate, if metal zinc powder is used to replace indium, it will cause the escape of highly toxic gas arsenic hydrogen; if neutralization hydrolysis is used to enrich indium, the pH value is generally required to reach 4. Under this condition, a large amount of zinc arsenate precipitate will be generated in the solution, resulting in low indium slag grade and difficulty in subsequent indium recovery. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for separating and enriching indium from a zinc-containing, indium-containing and high-arsenic leaching solution.

[0006] The objective of the present invention is achieved through the following technical scheme: a method for separating and enriching indium from a zinc-containing, indium-containing, high-arsenic leachate, comprising the following contents: adding lime to a leachate containing 0.5-2.0 g / L of indium, 5-15 g / L of arsenic, 10-40 g / L of sulfuric acid, and 100-150 g / L of zinc, stirring, neutralizing, and precipitating to adjust the pH value to 1.6-1.8, obtaining indium-rich gypsum slag and indium-poor liquid through liquid-solid separation, and using the indium-rich gypsum slag as an enriched product for recovering indium.

[0007] The temperature of the zinc-containing, indium-containing, and high-arsenic leaching solution is determined by the leaching process. No additional heating or cooling treatment is required during the neutralization process. Even if the temperature of the acidic indium-containing leaching solution drops to room temperature due to long-term storage, it does not need to be heated during the neutralization process.

[0008] The lime is added in the form of solid powder material or in the form of lime milk after slurry mixing.

[0009] The stirring speed is 200-400 r / m.

[0010] The beneficial effects of the present invention are as follows: in the present invention, after neutralization and precipitation, the residual indium content in the indium-poor solution is only 10-20 mg / L, and the precipitation rate of indium is not less than 98%, thereby achieving efficient separation and enrichment of indium. The neutralization process of the present invention does not generate harmful arsenic hydrogen gas, is simple to operate, and is easy to implement, thus solving the problem of separating and enriching indium from a high-arsenic indium solution. DETAILED DESCRIPTION

[0011] The present invention is described in detail below. Example 1

[0012] A method for separating and enriching indium from a zinc-containing, indium-containing, high-arsenic leachate, comprising the following steps: adding solid powdered lime to a leachate containing 0.53 g / L indium, 14.79 g / L arsenic, 39 g / L sulfuric acid, and 148.3 g / L zinc, stirring and neutralizing the leachate at a stirring speed of 200 r / m to adjust the pH value to 1.8, and obtaining indium-rich gypsum slag and indium-poor liquid through liquid-solid separation; the indium-rich gypsum slag is used as an enrichment for recovering indium, and the precipitation rate of indium is 98.1%; the residual indium content in the indium-poor liquid is 9.85 mg / L, and the indium-poor liquid is subsequently subjected to arsenic removal to recover zinc. Example 2

[0013] A method for separating and enriching indium from a zinc-containing, indium-containing, high-arsenic leachate, comprising the following steps: adding lime milk to a leachate containing 1.89 g / L indium, 10.35 g / L arsenic, 20.6 g / L sulfuric acid, and 109.75 g / L zinc, stirring and neutralizing at a stirring speed of 400 r / m to adjust the pH value to 1.6, and obtaining indium-rich gypsum slag and indium-poor liquid through liquid-solid separation; the indium-rich gypsum slag is used as an enriched product for recovering indium, and the precipitation rate of indium is 99%; the residual indium content in the indium-poor liquid is 18 mg / L, and the indium-poor liquid is subsequently subjected to arsenic removal to recover zinc. Example 3

[0014] A method for separating and enriching indium from a zinc-containing, indium-containing, high-arsenic leachate, comprising the following steps: adding solid powdered lime to a leachate containing 1.05 g / L indium, 5.11 g / L arsenic, 11.7 g / L sulfuric acid, and 122.32 g / L zinc, stirring and neutralizing the leachate at a stirring speed of 300 r / m to adjust the pH value to 1.7, and obtaining indium-rich gypsum slag and indium-poor liquid through liquid-solid separation; the indium-rich gypsum slag is used as an enriched product for recovering indium, and the precipitation rate of indium is 98.6%; the residual indium content in the indium-poor liquid is 15 mg / L, and the indium-poor liquid is subsequently subjected to arsenic removal to recover zinc.

[0015] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for separating and enriching indium from a zinc-containing, indium-containing, high-arsenic leaching solution, characterized in that The method comprises the following contents: adding lime to a leaching solution containing 0.5-2.0 g / L indium, 5-15 g / L arsenic, 10-40 g / L sulfuric acid and 100-150 g / L zinc, stirring, neutralizing and precipitating to adjust the pH value to 1.6-1.8, obtaining indium-rich gypsum slag and indium-poor liquid through liquid-solid separation, and the indium-rich gypsum slag is used as an enriched product for recovering indium.

2. The method for separating and enriching indium from a zinc-containing, indium-containing, high-arsenic leaching solution according to claim 1, characterized in that: The lime is added in the form of solid powder material or in the form of lime milk after slurry mixing.

3. The method for separating and enriching indium from a zinc-containing, indium-containing, high-arsenic leaching solution according to claim 2, characterized in that: The stirring speed is 200-400 r / m.