PROCESS FOR THE RECOVERY OF NON-FERROUS METAL VALUES FROM SULFIDE ORES AND THE REDUCTION OF GASEOUS EMISSIONS TO THE ATMOSPHERE THEREFROM

摘要

A process for roasting an admixture of an inorganic chloride and a sulfide ore for subsequent extraction of substantially all of the copper, nickel, cobalt and manganese values of the ore as water soluble salts and for reducing the emission to the atmosphere of large quantities of sulfur dioxide and chlorine formed during said process without the necessity of using chemical absorbing solutions. The process comprises mixing the ore with an inorganic chloride such as sodium chloride, lithium chloride, potassium chloride, calcium chloride and magnesium chloride, providing the mixture in a gas permeable state to a first stage heating or roasting zone while maintaining therein from about 80 to about 140 percent of the stoichiometric quantity of air therein, conducting exhaust gases from the first stage heating zone to a second stage heating or roasting zone which contains roasted mixture from the first stage heating zone, replenishing the first stage roasting zone with fresh inorganic chloride-ore mixture, trapping exhaust gases from the second stage heating zone in water and leaching the roasted mixture from said second stage heating zone with water to extract substantially all of said metal values as water soluble salts. The process reduces the emission to the atmosphere of sulfur dioxide and of chlorine by at least about 85 percent, and upwards of 90 percent in preferred embodiments.