Leaching, ores

Other hydrometaHurgical uses for resin have been smaH in comparison. Replacement of carbon as an adsorbent for gold [7440-57-5] from a cyanide [57-12-5] leached ore has been studied for many years, but remains in limited commercial use. A deterrent has been the failure to develop an efficient and... 

Other recovery methods have been used (10). These include leaching ores and concentrates using sodium sulfide [1313-82-2] and sodium hydroxide [1310-73-2] and subsequentiy precipitating with aluminum [7429-90-3], or by electrolysis (11). In another process, the mercury in the ore is dissolved by a sodium hypochlorite [7681-52-9] solution, the mercury-laden solution is then passed through activated carbon [7440-44-0] to absorb the mercury, and the activated carbon heated to produce mercury metal. Mercury can be extracted from cinnabar by electrooxidation (12,13). 

Amine extraction is used also in another important industrial process, the extraction of uranium from sulphuric acid leached ores, which uses trilauryl amine (TLA). In that case, the extraction reaction is... 

Heap leaching A general name for processes for leaching ores with various aqueous solutions in order to extract metals. It is an inexpensive process, normally used with low-grade ores. The leachate must be well contained in order to prevent contamination of groundwater. 

North and Wells (N7) described the design and operation of a rotary-film contactor for the solvent extraction of metals directly from leached ore slurries. It consists of an enclosed rotating assembly of closely spaced disks centrally mounted on a common horizontal shaft. The transfer of the metal to the solvent layer is effected by the rotating disks where a film of slurry is formed on contact with the leached ore at the bottom of the vessel. This contactor gave excellent uranium recovery from sulfuric... 

Acid leached ore Alkaline leached ore Uranium precipitate... 

Table 9.2-2 summarizes the various methods used for the treatment of direct leaching ores. Typical minerals are listed, and those that can be leached by sonoxidative dissolution (NOX) are indicated. Those requiring oxidants (OX) are also indicated. In some cases preireaiment is required, as in the case of reduction masting of nickel laleriles or vanadium ore which may be subjednd to an oxidative salt roast prior to nonoxidative dissolution. Also indicated in Table 9.2-2 are the typical lixiviants used in the process, the methods used for metal recovery, and the form of the fianl product produced. 

TABLE 9.2-2 Direct Leaching Ores, Indicating Coneral Methods of Treatment... 

Fme leaching ores, metallic Au. Ag Vanadium OX caustic Precipitation. electrowinning Metallic Au, Ag... 

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