Sulfuric Acid-Oxygen Leaching for In-Situ Extraction of Copper Chalcopyrite

Hydrometallurgical treatment of chalcopyrite by sulfuric acid based systems for primary recovery of copper is limited by the refractory nature of the mineral (Bartlett, 1973; Gerlach et al, 1973; Vizsolyi et al, 1967). At ambient temperatures and pressures, leaching of chalcopyrite is slow and current industrial processing is almost exclusively limited to conventional mining, milling, … Read more

Use of Calcium Sulfate Gypsum as a Fire Retardant

Although calcium sulfate dihydrate, commonly referred to as gypsum, has been utilized for some time in fiberglass reinforced polyester (FRP) applications, it does not have the fire retardant filler recognition of ATH. Gypsum is more commonly known for application in cement, soil and water treatment, plaster, and wall-board. Inherent characteristics of gypsum limit its use … Read more

Magnetic Separation of Sulphide Minerals

Laboratory investigations on the possibility for magnetic separation of sulphide minerals are reported. A survey of several sulphide ores and flotation concentrates shows that magnetic separation in most cases is not a suitable primary method of beneficiation. However encouraging results have been obtained in concentrate purification. Traditionally magnetic separation is associated with iron bearing materials/ … Read more

Pressure Oxidation Treatment

Since start-up in 1985 the Cannon Mine has produced and shipped a 170 g Au/tonne (5 oz Au/ton) flotation concentrate to various smelters for gold and silver recovery. Several processes have been investigated to economically produce dore’ at the mine site from the refractory concentrate. The designed pressure oxidation circuit utilizes a series of vertical … Read more

How to use Column Flotation to Reduce Silica

The requirement for higher quality pellets demands that the silica content be lowered to levels ranging from 0.25% – 2.0% SiO2. Reverse flotation (silica is floated away from the iron concentrate) has proven to be an economical and effective method for reducing the concentrate silica content to very low levels. Laboratory and commercial test-work has … Read more

Prevent Silver Jarosite Formation

Pressure oxidation of refractory (arseno)pyrites results in residues from which nearly all the gold can be recovered. This is not the case for silver. Under prevailing autoclave conditions, which favour hydrolysis and precipitation of ferric iron, the silver becomes associated with jarositic species, limiting its subsequent cyanidation to less than 10 %. Effective enhancement of … Read more

Pyrite Oxidation Kinetics

The oxidation kinetics of pyrite and refractory gold concentrates in acidified ferrous sulfate solutions in the presence of oxygen-sulfur dioxide gas mixtures has been studied. The effect of temperature, pulp density and gas composition were determined. The optimum oxidation rate was obtained at 80°C and 2 percent sulfur dioxide in the gas mixture. The oxidation … Read more

Eudialyte Magnetic Separation Recovery

The most common zirconium bearing minerals are zircon, the zirconium silicate ZrSiO4, typically produced from heavy mineral sands in Australia and India, and baddeleyite, the zircon dioxide ZrO2, produced for example at Phalaborwa. A much less common zirconium mineral is eudialyte, a trigonal calcium-zirconium silicate occurring in silica-undersaturated nepheline syenite complexes, such as the Lovozero … Read more

Dry Grinding Example

The claims which supply oxide and refractory ore feed to the Cortez milling facility are located in both Lander and Eureka Counties. These include the Cortez and Horse Canyon deposits all operated by C.G.M. Joint Venture. Other deposits outside the C.G.M. claim area include; Fire Creek, Buckhorn, Gold Bar and Tonkin Springs. These deposits all … Read more

Oxide Sulfide Copper Ores Leaching

The results of column leaching tests on 3 different mixed oxide/sulfide ores from a Chilean deposit are presented. The 3 samples contained different ratios of oxide copper minerals to chalcocite and chalcopyrite. The results of the column leach tests are interpreted in light of the shrinking core model for coarse particle leaching. The copper recovery … Read more