Chloridizing roasting tests on gold, silver, and copper

The object of the work was an endeavor to find a practical process for the treatment of lowgrade gold and silver ores, which are refractory to modern methods, and also to increase the extraction of copper in our present inefficient copper concentrating; plants. Hydro-metallurgy seemed to offer the best and most practical solution of the problem. The process upon which the experimental work is based consists briefly in first subjecting the ore to a chloridizing roast, thus converting the metals into chlorides, in which form the metals can be extracted by leaching. Before presenting details of the work, however, a brief outline of the old processes and methods will be given, showing what has already been accomplished in the hydro-metallurgy of gold, silver, and copper.