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Lime-gypsum Processing of McDermitt Clay for Lithium Recovery.
MISSING :15 pages
As part of its efforts to devise new and improved methods for recovering lithium from unconventional resources, the Bureau of Mines investigated a lime-gypsum-roast, water-leach technique for processing lithium-enriched (0.01-0.68 pct li) clays. This report presents the results of a study of the technical feasibility of extracting lithium from raw material representative of clay beds associated with the McDermitt Caldera Complex in Nevada and Oregon. Pellets suitable for bench-scale roasting studies were prepared from mixtures of minus 200-mesh clay, limestone, and gypsum, with water used as the pelletizing agent. Roasting pelletized charges at 900 deg to 1,000 deg c temperatures for 1- to 4-h periods produced calcines that leached readily, yielding water-soluble lithium sulfate (li2so4). A 5-3-3 (weight ratio) mix of clay, limestone, and gypsum produced calcines with the best leaching characteristics. More than 91 pct of the contained lithium was extracted from pelletized mix batches roasted in covered refractory boats. Lithium recovery decreased to about 87 pct when the mix was roasted under dynamic conditions in a gas-fired rotary furnace. A reaction mechanism was postulated which indicated that dilution and loss of so2 and oxygen in the combustion exhaust adversely affected the leachability of the dynamically roasted calcine.
IH; Report of Investigations
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division