Alumina Miniplant Operations-Separation of Aluminum Chloride Liquor from Leach Residue by Horizontal Belt Filtration

摘要

The Bureau of Mines has investigated the recovery of alumina by hydro-chloric acid leaching of calcined kaolinitic clay. Bench-scale studies indicated that horizontal belt filtration was a pratical method for separating the siliceous residue from aluminum chloride liquor generated in the leaching step. Miniplant-scale continuous testing was performed to evaluate the filter circuits and to compare filtration response of different calcined kaolin feed materials and of different agitator-baffle designs in the leaching reactors. Modifications in leaching reactor design made to decrease particle-to-particle attrition were successful and significantly increased filtration rates and decreased flocculant requirements.