Pyrometallurgical Recovery of Indium from Dental Metal Recycling Sludge by Chlorination Treatment with Ammonium Chloride

Abstract

In the present paper we address the novel chlorination process for recovery of indium selectively from dental metal recycling sludge which contains considerably high amount of indium. The process is based on the utilization of ammonium chloride, NH₄Cl, as chlorination reagent. It was found that indium could be successfully recovered from the sludge in the form of volatile indium chloride by heating the mixture of sludge and NH₄Cl at the temperature of 400°C under inert atmosphere. The influence of process parameters, such as composition of NH₄Cl, was investigated in order to achieve high process efficiency.