Cobalt Sorption in Ion-Exchange Column
The Bureau has developed a process using ion exchange to extract cobalt, a strategic and critical metal, from domestic copper leach solutions. These solutions are produced by dump or heap leaching of low-grade ores with dilute sulfuric acid and contain significant amounts of readily accessible cobalt. Although the cobalt concentrations in these streams are only […]
Leaching Method for Recovering Silver & Manganese
In support of its goal of maintaining an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines has investigated the feasibility of in situ and heap leaching to recover manganese from low- and medium-grade domestic manganese deposits and to also recover the silver found in some of these manganese […]
Bioleaching Preg Robbing Gold Ore
Refractory precious metal ores in which gold is encapsulated within iron sulfide minerals can be effectively treated by other leaching bacteria in addition to T. ferrooxidans. These include both facultative and obligate thermophiles. Use of thermophilic bacteria for microbial pretreatment of precious metal ores can offer economic advantages over common bioleaching processes in terms of […]
Borate Leaching – In Situ Recovery of Boric Acid
Figure 3 shows a flowsheet of the patented process which involves injection of acid into the deposit, recovery of boric acid-rich solution from production wells and crystallization of boric acid by solar evaporation. The preferred acid in the Duval process is hydrochloric rather than sulfuric acid. The higher initial cost of hydrochloric acid as compared […]
Bacteria Leaching of Gold Encapsulated in Pyrite
It is known that many of the gold and silver deposits are often associated with sulfide minerals, specially pyrite. Some of the precious metals in such ores are often found as very finely disseminated particles inside the sulfide crystals. The encapsulation of the precious metals particles in this manner makes their extraction very difficult, as […]
Biohydrometallurgy – Bacteria in Mineral Processing
Much research has been carried out on biohydrometallurgy over these last 25 years and is still being actively conducted all over the world. The interdisciplinary nature of this young branch of science and technology is reflected by the variety of experts involved: microbiologists, mining engineers, hydrometallurgists, physico-chemists, mineralogists, solid-state physicists and bio-chemists. This intensive research […]
Improve Performance of Copper Solvent Extraction Process
LIGHTNIN pioneered impeller developments in the early 1980’s that allowed axial flow impellers (A310) in the auxiliary mix boxes of SX plants to reduce shear and entrainment while providing good contacting of the aqueous and organic phases. However, the mixing technology of the primary pumper has not changed since its introduction. LIGHTNIN has studied the […]
Geotechnical & Construction Aspects of ON OFF Leach Pad
Project Description Exploration and development of the project by Rio Algom Ltd. began in 1981. Feasibility and design studies were ongoing in the 1980’s culminating in a decision to develop an open pit mine, a heap leaching facility and an SX-EW plant capable of producing 60,000 tonnes of fine copper per year. Construction began in […]
Solvent Extraction Stripping Methods
To remain competitive, the domestic metals industry must not only make advances in mining methods, but also in ore processing. One processing advancement under investigation is the development of nonconventional solvent extraction (SX) stripping techniques such as hydrogen, hydrolytic, and precipitation stripping. Solvent extraction selectively removes a metal from an aqueous solution into a solvent […]
Pressure Oxidation Leaching Process
Batch Autoclave Laboratory Procedures: The vessel used for the laboratory pressure oxidation process was a two-liter Parr titanium autoclave with dual impellers. It was heated and cooled externally and was pressurized with commercial-grade oxygen. A positive bleed of offgas was maintained in each test; the rate was measured in the offgas after the steam was removed […]