| 摘要 |
PURPOSE:To obtain aluminum silicate fine powder especially containing primary particles with extremely small particle diameters, being readily ground, by drying a uniform mixture of an aqueous solution of aluminum sulfate and silica powder or silica gel, thermally decomposing aluminum sulfate and further heat- treating the resulting material. CONSTITUTION:An aqueous solution of aluminum sulfate having <=0.3wt.% impurity containing alkaline (earth) metals is uniformly blended with silica powder or silica gel and dried at 80-160 deg.C, preferably 100-130 deg.C. Then the dried material is heated to >=700 deg.C to thermally decompose aluminum sulfate, further heat-treated at 1,200-1,550 deg.C and silica is reacted with alumina to form mullite as a main mineral. Then the reaction product is ground to give aluminum silicate powder having a composition of 15-35wt.% SiO2 and 85-65wt.% Al2O3, >=10m<2>g specific surface area and <=5mum particle diameter.
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