Zinc Electrowinning from Chloride Electrolyte
Chemical and electrochemical leaching processes using chloride solutions (FeCl3, HCl, CuCl2) and dry chlorination with Cl2 gas followed by leaching of the resultant chlorides are some of the methods considered for treating fine-grained Zn-Pb-Cu-Fe sulphide ores and concentrates. These processes eventually result in an impure zinc chloride liquor which, after purification using either solvent extraction […]
Solvent Extraction of Cobalt SX
The United States produces essentially none of the cobalt and less than 10 pct of the primary nickel it consumes each year. However, it has been estimated that U.S. resources of cobalt and nickel are 842,000 and over 15 million short tons, respectively. Present yearly domestic consumption of cobalt is about 9,000 short tons, while […]
Chloride Leaching of Silver and Precipitation Recovery of Ag
As part of the U.S. Department of the Interior, Bureau of Mines, mission to assure a viable domestic minerals and materials economy, research is being conducted to investigate methods for recovering accessory elements from solutions resulting from hydrometallurgical processing of base-metal sulfide concentrates. These types of sulfide concentrates have traditionally been treated by smelting procedures […]
Gold Hydrometallurgy – Refining to High Purity
We investigated chemical methods for producing high-purity gold from precious-metal-bearing zinc precipitates and steel wool cathodes. Precious-metal-bearing zinc precipitates and steel wool cathodes are unrefined products from conventional cyanidation and heap leaching-cyanidation operations. The zinc precipitates contained 14.40 pct Au and 0.35 pct Ag. The precious-metal-bearing steel wool cathodes contained 20.65 pct Au and 4.84 […]
Make Alumina using Hydrochloric Acid
Al2O3 used as feed for electrolytic cells in the production of aluminum metal is obtained in the United States from bauxite by the Bayer process. The United States is dependent on imports for its bauxite supply, and despite adequate world reserves rising prices and competition by other industrial nations for bauxite suggest a need to […]
Chlorination of Titanium Carbide
The purpose of the Bureau research described in this report was to devise a procedure for producing TiCl4 from titaniferous raw materials, especially those that are high in CaO content. This research supports the Bureau’s goal of maximizing the recovery of minerals and metals from domestic resources in order to assure an adequate supply of […]
Mine Waste Leaching
Formation and Transport of Acid or Toxic Leachate The factors which control the quantity and quality of leachate formed from mining wastes are many and complex. These factors include not only the physical and chemical characteristics of the waste, but also climatological, hydrological, geological, and biological factors. The method of waste disposal and the selection […]
Mine Tailings Waste Leaching & Groundwater Contamination
Each year the mining industry generates tremendous quantities of solid wastes as a byproduct of the mining and concentration or preparation of valuable ores, minerals and coal. In addition, the quantities of these wastes generated on a yearly basis is increasing due to: increased production resulting from rising demand, the depletion of near surface high-grade […]
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 […]