A SOFT-CONDITIONS METHOD FOR THE SYNTHESIS OF ZEOLITE-A FROM MECHANICALLY/THERMALLY-ACTIVATED AOLINITE.

摘要

The present invention is to provide a cost effective process for the production of Zeolite-A, by conversion of kaolin into metakaolin first, then by reaction of the metakaolin in an aqueous alkaline medium. The activation of kaolin into metakaolin is carried out either by a mechanical-thermal coupling ensured by the dry grinding of kaolin followed by its calcination under-air, or by a thermal-mechanical coupling ensured by the calcination under-air of raw kaolin followed by its dry grinding. Accordingly, the activated kaolin, or metakaolin, is fused in a mild concentrated alkaline medium, the whole continuously stirred and heated under reflux at a temperature between 80 and 98°C, and under atmospheric pressure during 6 hours. The solid crystalline product is finally recovered by vacuum filtration and washed thoroughly with distilled water till reducing the filtrate pH to 9, and dried in an oven at 80°C ovemight.