In refining copper, the metal is melted down in a reverberatory furnace in a more or less oxidizing atmosphere and then further subjected to an oxidizing smelting in order to eliminate the common impurities, most of which have a stronger affinity for oxygen than has copper. In these operations some of the copper is oxidized … Read more
A solution of lead-fluosilicate, containing an excess of fluosilicic acid, has been found to work very satisfactorily as an electrolyte for refining lead. It conducts the current well, is easily handled and stored, non-volatile and stable under electrolysis, may be made to contain a considerable amount of dissolved lead, and is easily prepared from inexpensive … Read more
Several methods, both wet and dry, for the assay of zinc-box residues from the cyanide process, have been described in recent years, and each of them has been claimed to be superior to all others. A paper, entitled “Assay of Zinc Precipitates,” was published in the School of Mines Quarterly to the purport that the … Read more
The ores of copper are usually associated with minerals containing arsenic, antimony and bismuth. Whatever the means adopted for extracting the copper, these metals are usually found, to a greater or less extent, in the product. There is, however, usually some elimination in the various metallurgical operations to which the ores are subjected, and some … Read more
The treatment of slimes has of late years been, the chief difficulty in connection with cyanide work, in which much time and money has been spent in endeavouring to find a practical solution of this problem. The processes at present in use are: Filter pressing, as practised in Western Australia. Decantation, as practised in South … Read more
The building of reverberatory furnaces (Fortschaufelungsofen) where ordinary brick, fire-brick and iron are comparatively cheap, is quite a different matter from the building of such furnaces in isolated camps, where proper material is only to be obtained at high cost and with long delays. Time is always a large factor in metallurgical operations, and the … Read more
The study of an entirely new series of alloys may be undertaken from a desire to obtain knowledge applicable to the perfection of industrial alloys, or merely to test certain theoretical considerations. In the case of antimony & tellurium alloys, the theoretical side only is at present important; but it is hoped that the results … Read more
Several interesting experiments were made in the sampling of the silver-lead bullion obtained from the water- jacket smelting-furnace. The smelting-plant is divided into two portions, known locally as the north furnaces and the south furnaces. The former group comprises nine and the latter six 80-ton water-jacket furnaces, besides which the south group has one small furnace used … Read more
The latest revised edition of Mr. C. A. Stetefeldt’s book on the Lixiviation of Silver-Ores, which appeared very recently, contains no mention of the volatilization of silver in chloritization-roasting—an omission which is the more remarkable in view of the fact that in former editions of the work this important subject was noticed. Moreover, Mr. Stetefeldt … Read more
Some months since, the attention of the author was directed to certain statements to the effect that the gold-contents of foul or extremely dilute cyanide-solutions could not be effectively precipitated in practice by the usual zinc cementation of gold called the “zinc-method”. Such statements caused all the greater surprise, because it is well known that … Read more