Dielectric Mineral Separator
Dielectrophoresis, or dielectric separation, can be defined as the separation of particles according to their dielectric properties. Directly related to the dielectric properties of a particle is the particle’s dielectric constant (K). The difference in K of minerals is often much greater than the differences in density, magnetic susceptibility, or electrical conductivity. To date, several […]
Mine Dewatering
What if the shaft were much larger, say, 300 m in diameter, or 3000 m, is the above approach to aquifer depressurization still valid? Is it feasible and practical to use wells to reduce the water inflow to a deep mine? If so, can the evaluation approach used in this paper be utilized? I believe […]
Density Separation of Materials by Using Magnetic Fluids
Continuously separate mixture of non-magnetic materials (such as scrap, precious metals, or certain ores) at a reasonable cost. Nonmagnetic materials of different densities are rapidly float/sink separated by an augmented lifting force produced in a magnetic fluid (liquid) by the effect of an external magnetic field. The magnetic fluid is a colloidal suspension of magnetite […]
Concentrate Regrind
We used the original flowsheet for two and a half years and made concentrates containing 16%-18% insol. Then we were asked to reduce the insol content as much as possible without additional capital expenditures in an effort to improve the smelting process. One of the 7 x 10 bail mills had been outfitted with four […]
Attrition Grinding Mill Design
As part of its mission to advance minerals technology, the Federal Bureau of Mines has conducted investigations to determine the feasibility of producing subsieve-size material by an attrition grinding method. The Bureau-patented technique involves the intense agitation of a slurry composed of the material to be ground, a granular grinding medium, and a suspending fluid. […]
Roasting of Copper Smelter Feed
Arsenic is produced in the United States as a byproduct from base metal ores. Although this production supplies only about one-half of the national demand, arsenic is generally not recovered but is treated as a troublesome impurity. Its complete recovery in domestic metallurgical plants could nearly supply the country’s arsenic needs, but complicated and inefficient […]
Citrate Process Analytical Chemistry
One goal of the U.S. Bureau of Mines metallurgy research program is to reduce the objectionable impact of mineral-processing operations upon the environment to the lowest possible level consistent with a viable minerals economy. The citrate process for flue gas desulfurization of (FGD) is a product of continuing Bureau research in pursuit of this goal, […]
Flotation of Chromite Ore
The Stillwater Complex in Montana (mainly the Benbow and Mouat deposits) contains an estimated 15.7 million short tons of ore containing 1.3 million short tons of recoverable chromium. This represents approximately 75 percent of available domestic chromite and could supply U.S. needs for about 4 to 5 years, but it is low in grade and […]
Wet High Intensity Magnetic Separation
WHIM is the short acronym for Wet High Intensity Magnetic Separation. At present, most U.S. iron raw materials are produced from magnetic taconites, which are ground to a nominal minus 270 mesh (53 micrometers), beneficiated by wet low-intensity magnetic separation, and pelletized. The taconite ore bodies generally contain 19 to 25 percent magnetic iron, defined as iron […]
Control Water Flow during Shaft Sinking
The importance of controlling water inflow during shaft development has been well known to those faced with the problem. Depending on the amount, temperature, and quality of the water, the extra costs of working in wet conditions can easily be several times that for the same work under dry conditions. I have heard estimates of […]