Galena brines

Gagarinite structure, 846 Galactose oxidase, 700 copper, 655 Galena brines, 853 depression, 783 dissolution, 787 humic acids, 861 Gallium isotopes... 

Lead sulphide (galena - PbS) is another likely candidate for hydrometallurgical processing particularly in the United States where, apart from the problems of the sulphur dioxide emissions, the lead toxicity problem is making it very difficult for the lead smelters to operate their conventional pyrometallurgical process and comply with EPA and OSHA standards. The total amount of lead mined in the United States is about 600,000 tons per year which, if fully converted, would yield about 100,000 tons per year of by-product sulphur. The Bureau of Mines in Reno, Nevada, have an active pilot plant study to produce lead via a hydrometal-lurigal process (2). In this process the common lead mineral galena is dissolved in an acid brine solution of ferric chloride. 

The possibility of using brine to slurry the ore in the presence of an oxidizer such as chlorine in order to extract metals from the more common sulfide minerals has been studied by Strickland and co-workers (Jl, S12, S13). The reactions of acid chlorine solutions with galena (PbS), pyrite (FeSj), sphalerite (ZnS), chalcocite (CujS), covellite (CuS), chalcopyrite (CuFeSs), bornite (CusFeSi), pyrrhotite (FeS), and arsenopyrite (FeAsS) were examined with respect to their reaction rates and mechanisms. 

Results from both approaches indicate that (i) high concentrations ( 100 mg L ) of lead and zinc can be present in oil-field brines only if the concentration of total H2S is at the pg level in such fluids, significant quantities of dissolved lead and zinc can be transported as carboxylate complexes (ii) lead and zinc in Mississippi-Valley-type ore fluids appear to be transported dominantly as chloride complexes and (iii) the brines are close to equilibrium with galena and sphalerite under the likely subsurface temperatures, pressures, and pH (Kharaka et al., 1987 Sicree and Barnes, 1996 Giordano, 2000). 

Doe, B. R., Brown, G. F. Preliminary lead isotope investigations of brine from the Red Sea, galena from the Kingdom of Saudi Arabia, and galena from the United Arab Republic (Egypt). Earth Planet. Sci. Letters 3,139—144(1967). 

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