Clay Flocculant
Under its mission to effect pollution abatement, the Bureau of Mines began intensified research seeking means for economically disposing of the large amounts of Florida phosphatic clay wastes and reclaiming the mined land. The clays, which are discharged from the processing plants at about 3 to 5 pct solids , have colloidal characteristics and are […]
Diatomaceous Earth Filtration of Cyanide Leach Liquors
In many instances, Diatomaceous Earth (DE) filtration could be considered a relatively recent technology. In the late 1800’s there were many references to the use of DE in small scale filtrations and in most instances these were laboratory curiosities. The use of DE in the sugar industry was proposed in the 1880’s, but this was […]
Cyanide Destruction in Gold Heap Leach
In the past 25 years there has been a wide expansion of the use of cyanide heap leaching by the mining industry. This process allows profitable recovery of gold and silver from low-grade ore. Heap leach pads are constructed on slight drainage grades and lined with an impervious clay and/or geotextile. Ore is stacked and […]
Heap Leaching Agglomeration
We investigated a particle agglomeration technique for improving the flow of leaching solution through heaps of clayey or crushed, low-grade gold-silver ores, wastes, and tailings. This technology has been adopted on a broad scale by the precious-metals-processing industry. This report presents information on five commercial operations that have benefited from agglomeration technology and that represent […]
Ferrochromium Alloys Manufacturing
As part of its effort to reduce the need for strategic minerals through conservation and to reduce the capital and energy requirements of mineral processing, the Bureau of Mines has investigated a method for preparing ferrochromium alloys containing less than 2 percent carbon. This method will conserve chromium and should reduce the capital and energy […]
Extracting Lithium
The Federal Bureau of Mines investigated extraction of lithium from non-conventional resources in keeping with its goal of maximizing minerals and metals recovery from domestic resources in order to assure an adequate supply of minerals to meet national economic and strategic needs. This report describes the results of bench-scale studies on the processing characteristics of […]
Electronic Ore Sorting Copper Ore
This process uses electronic ore sorting or “pre-concentration” as an added step before normal concentration to develop a processing system for the native copper ores. Successful ore sorting can lead to cost reductions in the following areas: Materials handling, and hoisting (if sorting is done underground). Capital and milling operations. Mill tailings disposal, as well as […]
Electrolytic Reduction using Coke Electrodes
The objective of this investigation was to reduce toxic Cr6+ in various waste processing liquors to less toxic Cr3+ while simultaneously removing copper. In addition to recovering a valuable copper product, removal of copper and reduction of Cr6+ in these liquors will substantially decrease the chemical demand and increase efficiency in waste treatment operations associated […]
Electric Arc Furnace Operation
The lack of domestic reserves of rutile and high-grade ilmenites to accommodate the projected increased demand for TiO2 has prompted the Bureau of Mines to investigate methods for recovering titanium from lower grade deposits. In addition, rapid depletion of domestic high-grade iron ore deposits constitutes a growing problem. The United States is well endowed with […]
Chromic Acid Solution Electrolytic Regeneration
Etching solutions containing hexavalent chromium ions (e.g., chromic acid) are used in brass finishing, printed circuit board etching, preparation of plastic for plating, anodizing, and various other industrial surface treatment operations. As the solutions are used, hexavalent chromium ions are reduced to their trivalent state, contaminants accumulate in the solution, and the effective acid concentration […]