Metal extraction through chlorine metallurgy

Abstract

Chlorination has been an important process step in the extraction of many nonferrous metals from their ores and concentrates. Some of the important chlorinating agents are gaseous chlorine, hydrochloric acid, ferric chloride, carbon tetrachloride and some alkali or alkaline chlorides like, NaCl, CaCl₂ and NH₄C1. Because of their high reactivity at a moderate temperature, selectivity in chlorination of the desired metal values and their easy availability with low cost, these chlorinating agents are being widely used in opening up the ores and minerals, for preparaton of pure metal chlorides and in recovery of metal values from the scrap and other wastes. In this paper, the chemistry of the chlorination processes in various stages of the extraction of some important metals, has been discussed briefly. Some of the industrial processes using Chlorine Metallurgy have been outlined. A review of the research and developmental studies made in recent years, on dry and aqueous chlorination of some metal oxides and sulphides by gaseous chlorine, ferric chloride, hydrochloric acid, carbon tetrachloride and through chloridised roasting, has been made, by highlighting the thermodynamics and the kinetics of the processes involved. A reference has been made on the merits of some low temperature chlorinating agents like carbon tetrachloride.