Method for recovering indium and tin from ITO waste targets by utilizing oxidation method

Abstract

The invention utilizes the characteristics that tin has two states of bivalence and tetravalence in the solution, and the difference of the pH values is great when the tetravalent tin and trivalent indium ions precipitate in the solution, so the tetravalent tin and trivalent indium ions can be controlled under a certain pH value; oxidant is utilized to oxidize tin ions into tetravalence to generate hydrolysis precipitation, while indium still remains in the water solution, thus achieving the complete separation of indium from tin. At the moment, the tin contained in the indium solution is lowered to 2ppm, aluminium cutter replacement can be directly carried out after vulcanization to ensure that the content of tin, cadmium, thallium and lead is less than 100 PPM, and the content of indium is greater than 99%; while the oxidized tin dregs return and leach, and finally coarse tin oxide can be obtained for sale after washing and roasting the leached dregs, and the grade of indium content is lower than 0.2%.

Description

technical field [0001] The invention relates to a method for recovering indium tin from waste ITO targets by an oxidation method. Background technique [0002] Indium is an important scattered metal element, and its compounds are widely used in semiconductor, electronics industry, atomic energy industry, etc. Among them, indium tin oxide (ITO) is the largest consumption of indium, accounting for more than 70% of the total consumption. The leftovers, chips and waste products produced during the production of ITO powder targets, as well as the targets after sputtering coating, are the largest sources of secondary resources of indium. The main components of ITO are: 70-75% indium, 7-8% tin, the rest is oxygen, and a small amount of impurities. [0003] The key to recovering indium from waste ITO targets is to consider the separation of indium tin and the quality and yield of crude indium. Although the process of using indium plates to replace tin from the ITO hydrochloric ac...

AI Technical Summary

Problems solved by technology

Although the process of using indium plates to replace tin from the ITO hydrochloric acid leaching solution can separate indium tin to obtain qualified crude indium, about 10% of the finished crude indium products need to be returned to the tin replacement process every day, and the recovery rate of indium is less than 95%. The grade of indium in tin is as high as 5-10%, so it is difficult to discard and sell directly as tin products

Images