Iron Oxide Superconcentrates by Caustic Leaching.
NTIS: PB 226 230 :11 pages
The removal of silica from commercial iron oxide concentrates by dissolution with sodium hydroxide was investigated by the Bureau of Mines as a means for producing supergrade concentrates. The effects of strength of solution, temperature, and digestion time on the extraction of silica were evaluated using eight iron oxide concentrates. Silica extraction from the eight concentrates was enhanced by autoclave leaching in the temperature range of 150 deg to 250 deg c and varied from 70 to 95 pct depending on the concentrate used. Superconcentrates containing less than 2 pct sio2 and more than 69 pct fe were made only when magnetite concentrates were leached in the autoclave. The investigation showed that it is not difficult to obtain a super-grade product if the gangue is mainly quartz.
IH; Report of Investigation;
NTIS Accession No.
NTIS: PB 226 230