| 摘要 |
PURPOSE:To synthesize a stevensite composed of Mg, Si and Na only, and contg. no metallic component of impurity by subjecting an aq. composition contg. basic magnesium carbonate and silica-sodium component to hydrothermal treatment. CONSTITUTION:The aq. slurry is obtained by uniformly mixing the basic magnesium carbonate (hydromagnesite, etc.) with the silica-sodium component selected among a group consisting of sodium silicate, sodium silicate and non-crystalline silica, non-crystalline silica and sodium hydroxide. The obtained mixture is fed into an autoclave, etc., and subjected to hydrothermal treatment at about 100-300 deg.C under a pressure of 0-100kg/cm<2> gauge. The product is obtained by allowing the synthetic stevensite obtained with the reaction to separate with solid-liquid separation, washing with water and drying. Thus the synthetic stevensite having excellent purity is produced with high yield under relatively mild hydrothermal synthesizing condition.
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