ALUMINA RECOVERY FROM IRAQI KAOLINITIC CLAY BY HYDROCHLORIC ACID ROUTE

Abstract

The extraction and recovery of alumina (Al2O3) from white kaolinite clay in hydrochloric acid solution was investigated on laboratory scale. The extraction rate was found to increase with calcination temperature (up to a certain limit), calcination time and acid concentration. Under optimum conditions of 720oC calcination temperature for 45 min with 28% HCl, by weight and 45 min leaching time at 100oC, alumina extraction was about 99 % .The recovery of alumina by gas (Hydrogen Chloride) precipitation technique has proven satisfactory and it was of about 93%, with purity of about 99.98% Al2O3.This purity of the produced alumina was found in accordance with that of commercial grade, which is in the range of (99 – 99.5)% Al2O3.