Cyanide Leaching Platinum Catalytic Converter Chemistry
Previous research by the U.S. Bureau of Mines showed that autoclave cyanide leaching of used automobile exhaust catalysts for recovery of platinum group metals (PGM) was technically feasible. This work involves a more detailed investigation of the chemistry of the dissolution of PGM in cyanide solutions. The PGM species in solution were identified by ultraviolet […]
Scrap Silver Recovery
The Bureau of Mines undertook a study of recovery of precious metal values from surplus and obsolete electronic gear as a part of its continuing effort to achieve maximum use and conservation of natural resources. During the early phase of the study it was learned that some military aircraft contained significant quantities of silver as […]
Precipitate Refining Method
This cyanide precipitate is unique in that it is apt to vary widely in composition in the course of very short periods of time, and a method of refining and melting that would prove highly satisfactory at one cleanup would yield almost a hopeless “mess” at a second. Table I gives a general conception of […]
Platinum Alloys with Tungsten & Molybdenum
Metallurgical research has discovered many an alloy possessing properties not combined in any single metal, and progress still consists chiefly in the investigation and utilization of alloys. In the case of iron, the demands of automobiles, high-speed machines and high-duty engines have led to the production of special iron alloys which will meet any reasonable […]
How to Assay and Evaluate a Gold Bar
The Bureau of the Mint of the United States Treasury maintains offices for the purchase of gold-bullion, and this paper describes an investigation to establish the reasonable differences in the assay-results at the various institutions which may be commercially allowable in the settlements between them. Beginning with the comparative assay of proof-gold at the Philadelphia […]
Laboratory Gold Ore Chlorination Testing Procedure
Experience has shown how difficult it is to obtain information regarding laboratory tests in connection with the chlorination-process for the extraction of gold from its ores, and I therefore present the following method, somewhat in detail, for the benefit of those who may desire to pursue research work in this field. The ore chosen was […]
Refining Base Metal Bullion & By-Product Treatment (Pb, Cu, Zn) Bars
Here is a short account of the treatment of the base bullion for the recovery of lead, silver, and gold, and for the treatment of by-products. Appended is a short description of the chief facilities of plant which have been adopted to overcome the main difficulties in the refining of lead. The difficulty of obtaining fair samples […]
Gold Leaching of Pyrite Concentrate
The ore consisted of quartz, in which, above the 250-ft. level, the iron-minerals were largely oxidized and some free gold was visible; below that level few traces of oxidation occurred, and pyrite constituted the principal mineralizer in the quartz, together with occasional pockets of galena and a few eccentric specks of covellite. The 20-stamp mill […]
Bromine Cyanide Gold Leaching: Cyanogen Bromide
Although the bromo-cyanide or Diehl process for the extraction of gold from its ores is used on several of the Kalgoorlie mines, very little information has been published on the original process, and no details are available from the various mines now using it. The following description of the process as carried on at the […]
Gold Ore Deposits
The volcanic source of gold deposits is also most clearly indicated in the Cripple Creek district, Colorado, where the deposits of commercial grade are either within a complex volcanic neck or extend for only short distances into the surrounding rocks. It is true that similar mineralization has taken place for considerable distances from the neck, […]