This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 edition. Excerpt: ...step. The production of ferric chloride at this point is advantageous in that it dissolves copper oxide, copper sulphide or metallic copper, which remained unaffected by the roasting, producing copper chloride, and this ferricchloride also maintains the copper chloride in the cupric condition. The gold and silver in the ore are brought into solution by converting all the copper into cupric chloride and then adding a small amount of chlorine, chlorous, or chloric compounds. The chlorides of silver and gold being soluble in calcium chloride solutions may afterward be precipitated with the copper and subsequently separated. After leaving the reaction drum the mass of gangue, solution, and precipitates is subjected to filtration. The solid matter forms a cake which consists of the gangue in the ore except a small amount of iron and alumina which have been taken into solution and the calcium sulphate precipitate already mentioned. The solution comprises a carrier in which has been dissolved the metals to be recovered, a small amount of iron and alumina and any zinc which may have been in the ore; the arsenic will have been separated by filtration, as it has been rendered insoluble. The solution is then subjected if necessary to a further oxidizing operation in order to be sure that the metals are all combined at their highest valency. The solution is then in condition for treatment for the separation of the dissolved metals. The precipitation of iron and alumina may be made by cupric oxide, hydrate or calcium carbonate, and as this precipitate will carry some copper it is returned to the amphidizer, or roasting furnace, after having been removed from the solution by filtration. In the amphidizer the iron and alumina in the precipitate are...