There are widespread nickel resources around the world, but divided principally between nickel sulfide or laterite (oxide) resources. Historically production has been dominated by sulfide ores but future production is increasing shifting to laterite ores. The principal reason for this historically is that sulfide ores are easier to process, through conventional mining, smelting and refining, co...

in the present work, the extraction of zinc from a sphalerite concentrate using sodium nitrate as an oxidant in a sulfuric acid solution was investigated. the effective parameters such as the temperature, sulfuric acid and sodium nitrite concentrations, stirring speed, particle size, and solid/liquid (s/l) ratio were analyzed. the dissolution rate increased with increase in the sulfuric acid an...

 Cyanidation is a relatively simple and cheap technology to treat gold-containing ores. However, this process is not completely effective in refractory gold-bearing sulfide ores. In the case of very low-grade ores, biooxidation is an attractive alternative pre-treatment to render the gold amenable to extraction. This process utilizes the ability of acidophilic bacteria to oxidize the sulfide m...

Iron occurs mainly as oxide ores, though it is also found in smaller quantities as its sulfide and carbonate. These other ores are usually first roasted to convert them into the oxide. On a world scale the most important ore is haematite (Fe2O3), but in New Zealand the starting materials are magnetite (Fe3O4) and titanomagnetite (Fe2TiO4). The oxides are reduced with carbon from coal, through t...

Tertiary low sulfidation (LS) epithermal deposits in the western USA often show evidence of the former presence of nanoparticle-sized precious-metal and silica phases in the highest grade (bonanza) ores. Here, nanoparticles are defined to have a size less than ~10 m. The ore-mineral textures that formed from aggregation of nanoparticles (or colloids) observed to date in these ores include elect...

To help understand the mechanism and control of Hg uptake in Hg-methylating bacteria, we investigated the effect of sulfide on Hg methylation by pure cultures of the sulfatereducing bacterium Desulfobulbus propionicus (1pr3). Our previous research in natural sediments has suggested that Hg methylation occurs most rapidly when sulfide concentrations favor formation of neutral dissolved Hg-S spec...

Supergene oxidation-leaching and secondary sulfide enrichment in the SarCheshmeh porphyry Cu-Mo deposit generated a supergene profile to depths of 20 to 80 meters with oxide ore reserve about 22 Mt. @1.08% Cu and sulfides ore [email protected]% Cu. Geochemical distribution and behavior of trace metals associated with Cu namely Mo, Au, and Ag in the supergene profile of the SarCheshmeh were po...

The increased rate of solubilization of sulfide ores of iron and copper caused by Thiobacillus ferrooxidans has been attributed either to direct action of the bacteria on the ore or to an indirect effect whereby the ferric ion is presumed to oxidize the ore and is returned to the active, oxidized state by the iron-oxidizing bacteria. Attempts by M. P. Silverman (3) to demonstrate that microbial...

To help understand the mechanism and control of Hg uptake in Hg-methylating bacteria, we investigated the effect of sulfide on Hg methylation by pure cultures of the sulfate-reducing bacterium Desulfobulbus propionicus (1pr3). Our previous research in natural sediments has suggested that Hg methylation occurs most rapidly when sulfide concentrations favor formation of neutral dissolved Hg-S spe...

This review has as its underlying premise the need to become proficient in delivering a suite of element or metal products from polymetallic ores to avoid the predicted exhaustion of key metals in demand in technological societies. Many technologies, proven or still to be developed, will assist in meeting the demands of the next generation for trace and rare metals, potentially including the br...