Study On Extracting Indium From Indium Antimonide

Indium is a representative scattered metal. It is very rare and dispersed in the earth’s crust, and it’s often associated in other minerals. Indium is widely used in a lot of different fields due to its advantages of low melting point, high boiling point, good electrical conductivity, strong light permeability, good ductility and good plasticity. With the rapid development of high and new technology industry such as electronic industry, the market demand of indium is increasing. However, the output of native indium is far away from meeting the market demand of indium. Thus, to speed up the research and development of recycling indium becomes an urgent problem to be solved. This paper studies the process of extracting indium from indium antimonide. It has important significance of saving resources, protecting the environment and creating economic benefits.Hydrometallurgy is used to extract indium from indium antimonide in this paper. The process route is explored through theoretical calculations and exploratory experiments. At first, indium antimonide is leached by different leaching agents and leaching methods, respectively. Then indium’s leaching rates of different leaching processes are compared, and it comes to the conclusion that indium antimonide oxidation leached by HNO3 has the highest leaching rate of indium, and it is simple operated without impurities. So HNO3 is chosen to be the leaching agent. After HNO3 oxidation leaching indium antimonide, solvent extraction method and hydrolysis precipitation method are used to separate indium and antimony in the solution, respectively. The experimental results indicate that hydrolysis precipitation method has the advantages of short process flow, low cost and high separation rate of indium and antimony. So hydrolysis precipitation method is chosen as the separation method. Then In(OH)3 is redissolved by HCl, and metal displacement method is used to displace indium ion in the solution. Due to aluminium piece displacing indium has short displacement period, the sponge indium is easy to be collected and no need to heat, aluminium piece is chosen to be the displacer. Finally, the process route of “oxidation leaching by HNO3- fractional hydrolysis precipitation- displacing by aluminum piece” is determined to extract indium from indium antimonide.After determining the process route, the effect of different technological parameters on the extraction rate of indium is investigated through single factor method. The optimal technological conditions are:(1) In the process of oxidation leaching: HNO3 concentration is 8 mol/L, liquid-solid ratio is 3.5:1, leaching time is 20 min, leaching temperature is 25 ℃, partical size of indium antimonide is less than 124 μm.(2) In the process of separating indium and antimony: antimony’s hydrolysis pH is 1.4~1.6, antimony’s hydrolysis time is 48 h, indium’s hydrolysis pH is 3.4, indium’s hydrolysis time is 24 h.(3) In the process of displacing: displacement pH is 1.2~1.6, displacement time is 3 h. Under these conditions, the extraction rate of indium is 92.09%, indium content in crude indium is 97.70%. At last, crude indium is characterized by EDS, XRD and SEM.This paper develops a process route of extracting indium from indium antimonide. It has the advantages of high extraction rate of indium, short process flow, low cost, simple operation and low pollution to the environment. This process can recycle indium from indium antimonide waste effectively. It helps to relieve the contradiction between production and demand of indium, and realizes the sustainable development of indium resources. It also plays the role of protecting the environment and creating economic benefits. The subject has very important theoretical and practical significance.