PROCESS FOR PREPARATION OF ULTRA FINE, LOW BULK DENSITY ALUMINA TRI HYDRATE

摘要

The invention relates to the ultra fine, low bulk density alumina tri hydrate and process for preparation thereof having packed bulk density 0.15-0.35 g/cc, with median diameter size from 0.2 to 1.0 micron through special precipitation method. Precipitation test has been carried out using sodium aluminate liquor is treated with NaHCO3 at 8 to 9 pH with aging time from 8 to 16 hours. Precipitation was carried out at 35 to 55 deg. C, for 24 to 48 hours using 8 to 12 gpl to gel as seed. Passing of CO2 at 70 deg.C. for 4-6 hours is optionally employed as per the precipitation requirement. The resulted precipitated slurry is then filtered, washed and dried. The dried alumina tri hydrate with bulk density of 0.15 to 0.35 g/cc with median diameter (d50)= 0.2 to 10 micron was achieved in this process under optimum conditions.