Comparison of Indium and Gallium Dissolution from Zinc Oxide Concentrate in Different Acidic Solutions

摘要

While some of leaching experiment data on dissolving indium and gallium from sphalerite has been performed during the prior years, no comparison of different acidic solutions has ever been made. This study is generally divided into two sections, with each section devoted to impact aspects of acid type on prominent parameters with focus on the dissolution of gallium and indium from zinc oxide concentrate. Secondly, the study is concentrated on complex formation and stability constant to justify the consequences. Maximum dissolution of the indium and gallium was occurred with nearly results of each other as follows: hydrochloric acid > sulfuric acid > nitric acid; hence, the hydrochloric acid had relatively a little more potential rather than other acids to dissolve indium and gallium whose differences in dissolution could be explained by differences in stability constants. The dissolution optimal conditions were determined for zinc oxide concentrate including acid concentration of 6 molarity, leaching in 90 degrees C temperature for 4 h, solid-to-liquid ratio of 1: 20 g/mL, particle size of +38-53 mu m and agitation speed of 600 r/min. The results showed that relation between changing of (dissolution time, temperature, acid concentration) values and kind of the employed acid has prominent effect on the amount of dissolution variation, while relation between changing of (agitation speed, solid-to-liquid ratio, particle size) values and kind of the employed acid has not important effect on the amount of dissolution variation.