Dissolved Oxygen in Cyanidation with Hydrogen Peroxide
Improvement of current leaching technology was found necessary when processing ores which are more difficult to leach because they generate highly viscous, air-rejective pulps. Cyanidation of these pulps has to run at low oxygen concentrations if the conventional aeration technique with compressed air is used. Since the dissolution rate of precious metals mainly depends on […]
Carbonate Buffer in Soil
Data from analysis of mineralogy, water extracts, and groundwater demonstrate the significance of the neutralization of the acid from the tailings by the carbonate in the soil on the processes of retardation of contaminants. The observed data are consistent with the results of the thermodynamic calculations done with PHREEQE for the concentrations of components exiting […]
Heap Leach Solution Irrigation
The application of drip irrigation in Heap Leach, has been proven to be a significant improvement over conventional spray irrigation techniques. While still under evaluation, it is evident that the use of drip irrigation will increase the operating time of a heap leach during winter and may significantly reduce operating costs through reduction in reagent costs […]
Vacuum Induction Melting
The effect of fluoride inclusions on the properties of titanium produced from the Bureau of Mines developed induction slag melting process is of concern to the titanium industry. The objective of the research was to determine the effect of removing the nonconductive molten calcium fluoride (CaF2) slag used as an insulator between the titanium and […]
Electrowinning Mercury in Gold Pregnant Solution
Many gold-bearing ores in the Western United States also contain small amounts of mercury. The presence of mercury creates potential pollution and health hazards during several steps in gold processing. An investigation was undertaken by the Bureau of Mines to develop techniques for removing mercury from cyanide mill solutions by selective electrowinning to reduce the […]
Secondary Copper Converter Dust Metal Recovery using Ammoniacal Carbonate Leaching
Effective recycling or disposal of flue dusts is a continuing problem, particularly for secondary smelters treating low-grade Cu scrap. The Bureau of Mines investigated a variety of flue dust treatment approaches and demonstrated the technical feasibility of a bench-scale alkaline method that includes leaching, cementation, precipitation, and roasting. Flue dust was leached at room temperature […]
Manganese Ore Leaching by Dissolved Sulphur Dioxide
The Bureau of Mines conducted column-leaching tests on 25 domestic Mn ores to determine the feasibility of extracting Mn by in situ or heap leaching with dissolved sulfur dioxide (SO2) solutions. The ores tested were obtained from deposits in Arizona, Arkansas, California, Colorado, Maine, Minnesota, Nevada, and South Dakota. Dissolved SO2 was found to be […]
Aluminium Recycling Furnace Refractories
We studied the problem of corundum formation on refractory linings in aluminum recycling furnaces. A laboratory test was developed for evaluating refractories in contact with molten recycled aluminum and identifying the mechanism of corundum formation. A test apparatus was designed and constructed to evaluate the performance of refractory samples. Corundum mechanism formation studies indicated that […]
Electrodewatering of Muds
Research was conducted by the Bureau of Mines to determine the feasibility of using electrokinetic densification to dewater Bayer process red mud, magnetic black mud prepared by pressure digestion of red mud in the presence of ferrous sulfate, and magnetic black mud formed by simulated Bayer digestion of Jamaican bauxite with added ferrous sulfate. Tests […]
Effect of Fluoride on Slag
The effect of fluoride inclusions on the properties of titanium produced from the Bureau of Mines developed induction slag melting process is of concern to members of the titanium industry. The objective of the research was to determine the effect of CaF2 inclusions on the properties of titanium and its survival rate during melting. The […]