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Extraction of Chromium from Domestic Chromites by Alkali Fusion.
Hundley-GL; Nilsen-DN; Siemens-RE
MISSING :14 pages
The Bureau of Mines has devised a procedure to recover chromium chemicals from low-grade domestic chromites, which contain silicon and aluminum impurity levels that are too high to permit processing by present industrial processes. The Bureau procedure consists of reacting chromite with molten sodium hydroxide (naoh) under oxidizing conditions to form sodium chromate (na2cro4). The reaction product is leached with methanol to remove the majority of the unreacted sodium hydroxide, then with water to remove the sodium chromate and the remainder of the sodium hydroxite. The sodium chromate product is recovered by evaporative crystallization from the aqueous solution. This report presents results of laboratory tests to determine the optimum fusion conditions and the chromium extractions obtained from several domestic chromite concentrates. These concentrates are from a variety of sources, including the Stillwater Complex in Montana, Kanuti River-Caribou Mountain, Red Bluff Bay, Kenai Peninsula, and Kodiak Island areas in Alaska, deposits in northern California, and a nickel-cobalt laterite from southern Oregon. All of these concentrates were successfuly treated by the Bureau procedure. The best chromium extractions obtained for each of these materials ranged from 69.5 to 98.9 pct.
IH; Report of Investigations
AK; CA; MT; OR;
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division