ACTIVATING BAUXITE TAILINGS FROM BAO LOC, LAM DONG MINE TO USE AS ADSORBENT MATERIALS

Abstract

This study aims to optimize the activating process of bauxite tailings from Bao Loc, Lam Dong mine. Chemical and physical activation were occured, sulfuric acid (H2SO4) 2M was introduced to remove impurities in the structure of bauxite tailings and high temperature was used to form porous structure to match with high surface area requirements of the adsorbent. Response surface methodology (RSM) was employed to test the determinant parameters, including acid amount, activating time, heating temperature and time. Experiment designs and regression models were performed by Design Expert 11 software and the results indicated that models were quite compatible to experimental data and the correlation coefficient R2 reached to 0.99. Results showed that acid amount at 4,7 mL/g,
activating time at 5,7 hours, heating temperature at 535 ℃ in 1,37 hours are the optimal condition for activating process. The product is used for phosphate adsorption, the adsorption capacity reaches 0.599 mgP/g. This study suggested the way to use bauxite tailings as an adsorbent in wastewater treatment, having both environmental significance and
economic value.