INTEGRATED SERPENTINITE PROCESSING METHOD RESULTING IN PURE SILICA PRODUCTION

FIELD: industrial inorganic synthesis. ^ SUBSTANCE: invention comprises processing of serpentinite to produce following commercial products: pure silica, magnesium compounds, including magnesium chloride, magnesium metal, carnallite, iron- and nickel-containing concentrates. Serpentinite is leached with hydrochloric acid solution containing 10-21% HCl at 60-100 and liquid-to-solids ratio (3-10):1 for 2 to 6 h under discontinuous or continuous countercurrent conditions to yield magnesium chloride solution and silica. The former is purified via two-step neutralization: first with brucite or caustic magnesite at 80-90 to pH 3.5-4.0 and then with sodium hydroxide solution to pH 6-7 including addition of sodium sulfide or hydrosulfide. ^ EFFECT: increased purity of silica product and enlarged number of commercial products and/or semiproducts. ^ 4 cl