Abstract
In an effort to utilize domestic low-grade resources to extract chromium, mouat chromite concentrates from Stillwater Complex, Montana, were subjected to a sodium hydroxide or caustic soda roast and water leach bench-scale method. Although the soda roasting method has been known for quite some time, there are some problems associated with the roasting, particularly with lower grade chromites with lattice and gangue impurities. Using advanced electron-optical and x-ray microanalytical and macroanalytical techniques, the mechanics occurring in the soda roasting step have been revealed. The roasting step is the key to this overall process, and the rate-limiting steps have been identified, allowing substantial improvements in chromium extraction yields.
