For some decades now, the use of gravity separation techniques to recover valuable minerals has been relatively neglected in comparison to the developments in flotation and hydrometallurgical technology. However, more recently, there has been a resurgence of interest in gravity separation, especially in utilizing its low cost to improve the economics of high tonnage and/or low … Read more
Climbing gold and silver prices during the 1970’s awakened dormant interest in mining these metals in many districts. Since gold and silver deposits frequently can be profitably mined by small operators, a mix of mining activity has been created, comprised of large and small companies, both experienced and unexperienced. A key factor in the profitability … Read more
Acid ferric sulfate solution has been used for heap and dump leaching of low-grade chalcopyrite ores and is being considered as a possible lixiviant for the hydrometallurgical processing of copper sulfide concentrates. For many years, researchers have attempted to explain the leaching behavior of chalcopyrite, since the reaction rate kinetics are extremely slow and seem … Read more
Almost all aluminum in the United States is produced from imported bauxite or alumina. This country has, however, more than adequate domestic nonbauxitic alumina resources that could alleviate dependency on foreign sources. For both economic and security reasons, the Federal Government has had a longstanding interest in the development of alternative technology that would allow … Read more
Since the use of potential field methods in the search for cordilleran precious metal deposits provides information on the three- dimensional locations of intrusive margins detailed potential field data would be most useful. High quality, detailed aeromagnetics and gravity information is not generally available in the initial prospecting stage, however. Regional aeromagnetics and gravity are … Read more
Electrostatic separation is one of the most misunderstood physical processes used to beneficiate minerals. Nonetheless, millions of tons of titanium ores, iron ores and other minerals are processed every year economically, efficiently and safely. Over the past ten years major advances in electrostatic separation and its application have occurred. New processes include dewatering clay slurries, … Read more
At present, in the United States, municipal solid waste (MSW) is generated at a rate of 3 to 5 lb/d per person. It contains about 8 pct ferrous metallics. Projections indicate -11 MMton/yr of this valuable ferrous scrap is being discarded Discarded MSW magnetics are equivalent to approximately 15 pct of the total U.S. 1982 … Read more
The Bureau of Mines has investigated an electrolytic recycling process to recover lead from scrap batteries as part of the effort to improve secondary recovery of metals, minerals, and other values from waste products. This process eliminating sulfur dioxide (SO2) generation and minimizing particulate lead emissions, is an acceptable alternative to the pyrometallurgical processes currently … Read more
Sulfide ores are generally concentrated by grinding with steel media followed by flotation. Interactions between the grinding media and sulfide minerals adversely affect the floatability of the sulfides, increase the corrosive wear of the grinding media, and result in unrecovered sulfides in the flotation tailings leading to a loss of natural resources and the release … Read more
The basic condition controlling the choice of a dump or heap leaching process versus a fine grinding-agitation leaching process is the grade and tonnage of the ore body. Low grade ore and small tonnages are best treated by a low-cost method such as dump or heap leaching. The permeability of the material in a dump … Read more