Reduction of silica from complex calcite ore for use in seawater magnesia production

Rao, G. V. ; Bhaumik, S. K. ; Biswal, S. K. ; Sastri, S. R. S. ; Senguta, D. K.
Organization: Society for Mining, Metallurgy & Exploration
Pages: 7
Publication Date: Jan 1, 2000
The amenability of a calcite-bearing ore to the reduction of silica to below 0.2% by physical beneficiation was studied. The objective was to use the ore as a raw material for seawater magnesia production. The ore contains complex gangue minerals such as diopside, forsterite, phlogopite, clinohumite, graphite and quartz. These contribute to around 25% acid insolubles with 6% SiO2. Reverse-flotation studies using various cationic collectors with tannin as a depressant indicated the possibility of reducing the acid insolubles to around 5%. Direct flotation of calcite with anionic sodium oleate in the presence of sodium silicate and lactic acid as a depressant indicated the possibility of reducing the acid insolubles to below 3% and the SiO2 to from 0.2% to 0.3%. Lactic acid was found to be an effective depressant of the complex gangue minerals in the ore.
Full Article Download:
(435 kb)