高硅碱浸渣提铟

Extracting indium from basic leached residue bearing high silicon

碱浸渣是碱熔 浸出提锗后的铟渣,含铟量和含硅量较高,采用常规酸浸时会产生硅胶而难以过滤。分别用高温高酸浸出、硫酸化焙烧 浸出和预处理 浸出方法对高硅碱浸渣提铟进行研究。研究结果表明:这3种方法都能解决过滤难的问题,但采用预处理 浸出方法时铟的回收率最高。采用预处理 浸出提铟方法,即碱浸渣经过特殊处理后用硫酸浸出,在液固比为5∶1,硫酸初始质量浓度为120～150g/L,温度为80～90℃时搅拌浸出2.0h,铟的浸出率高达95%。采用萃取 置换方法从浸出液中提取ω(In)>98%的粗铟,经电解精练制得了ω(In)>99.99%的精铟;从碱渣到粗铟,铟的直收率为90%。

The basic leached residue containing indium and silicon was produced after extracting germanium by the basic molten-leaching process. When the residue is leached by general acidic solution, a silicon colloid is formed to make filtration of acidic leached solution to be difficult. Tree processes for treating the residue to recovery indium is high concentration acid at high temperature, sulphation roasting-leaching and preparation-leaching respectively, which can all resolve the difficult filtrate problem of leached solution. For recovery rate of indium, the third process is the best one with leaching rate of 95% under the optimum conditions such as mass ratio of liquid to solid being 5, beginning acid concentration of 120～150 g/L, at temperature of 80～90 ℃ for 2.0 h. Rude indium more than 98% was produced from the acidic leached solution using the extractive-cement process. From rude indium, refined indium more than 99.99% by electrolysis refining process was prepared. The direct recovery rate of indium is 90% from the basic leached residue to rude indium.