Metal Dissolution from Silver Copper Alloys in Ammonia
The dissolution behavior of silver and copper from silver/copper alloys in ammoniacal solutions has been investigated using a rotating disc. Oxygen was used as an oxidant. The effect of composition of alloys, concentration of lixiviants, stirring speed and temperature on the overall dissolution kinetics has been studied. Theoretical Background The dissolution of copper and silver […]
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, […]
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 […]
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 […]
Rhenium Extraction by Leaching in Ammonium Iodide Iodine
Pure rhenium is a refractory metal with a very high melting point of 3180°C. Extraction of rhenium from molybdenite concentrates and other primary sources has been studied for many years. Hydrometallurgical methods using Br2, HNO3, Ca(OH)2, NaOH or Na2CO3 have been investigated. Recently, a new process using halogen salts and ammonium as well as oxygen […]
Bioleaching Cadmium Sulfide
The applicability of electrochemical techniques in the elucidation of intermediate reactions in the bacterial oxidation of cadmium sulfide minerals has been demonstrated. Furthermore, it was found that the bio-oxidation process was solid-state diffusion controlled. Greenockite (CdS) and hawleyite (CdS) are the most important cadmium minerals, which occur as minor constituents in ores of zinc, lead […]
Acid Leaching Copper Flotation Concentrate
As an alternative to Acid Leaching, Copper Chalcopyrite (CuFeS2) concentrates are processed traditionally by smelting, which results in sulfur dioxide (SO2) emissions. The development of a hydrometallurgical process for recovery of metals from concentrates of Cu ores offers industry a low-cost, low-pollution alternative to the traditional pyrometallurgical practices. The hydrometallurgical leaching of chalcopyrite with acid […]
Solvent Extraction of Iron
The process to be presented makes use of a commercial mixture of highly-branched monocarboxylic acids with the trade name of “Versatic 10” (Shell). The formula may be presented as: where the total number of carbon atoms in the molecule is about 10. In short the Versatic acid will be termed RH. The organic acid RH […]
Sulfide Oxidation
The first leaching step is the release of trace metals from the mineral phase due to sulfide oxidation. Sulfate was the ultimate reaction product in both the laboratory and the field, a result of the pH and oxidizing conditions which prevailed, and the relatively long reaction time. The rate of sulfide oxidation observed in batch […]
Ferric Chloride Thiourea and Brine Leaching to Extract Ag-Au
Independent mine operators have difficulty marketing complex gold-silver concentrates and ores. Generally, complex sulfide concentrates and ores cannot be handled by existing smelters. Even when handling them is technically possible, smelter charges and transportation costs become limiting factors. Hydrometallurgical methods are seriously being considered to provide a simple, inexpensive, low-pollution process to treat complex gold-silver […]