Efficient deposition of indium by cementation from chloride solutions

The possibility and the main characteristics of cementation applied for indium recovery from aqueous chloride and sulphate solutions were considered theoretically and examined experimentally. Aluminium and zinc, in the forms of plates and powders were examined as reducing agents. It was found that indium can be cemented on Al or Zn surfaces best in chloride solutions. Zinc plate proved to be inefficient, however Zn powder performed well. In the case of aluminium, both the plate and the powder worked well, and virtually complete recoveries of indium could be achieved within 10–60 min - depending on the pH and temperature of the solutions. The produced sponge can be detached easily from the Al plate and efficiently melted under protective atmosphere, vacuum or salt flux. The purity of the produced sponges can be generally above 99.9%, and the cementation on Al plate produces the purest indium.