APPLICATION OF THERMOGRAVIMETRIC ANALYSIS FOR ESTIMATION OF TRI-HYDRATE ALUMINA IN CENTRAL INDIAN BAUXITES - AN ALTERNATIVE FOR CLASSICAL TECHNIQUES

摘要

Tri-hydrate alumina or gibbsite (Al_2O_3.3H_2O) content in bauxiteis a fundamental quality parameter in the Bayer alumina processusing low temperature digestion. Classical techniques availablefor its estimation are time consuming and prone to standard andnon-standard sources of error. Extensive studies on analysis ofsamples from Central Indian bauxite sources usingthermogravimetry over varied temperature ranges and comparisonwith that of the data obtained from classical techniques, haverevealed that loss of molecular water at different temperatures inthermo-gravimetry provides a meaningful tool to correlate withtri-hydrate alumina content by applying relevant correction factorsderived from the experimental data at different concentrations oftri-hydrate alumina. The studies also have found that the thermogravimetricanalysis can be used as a very fast and dependabletechnique with higher levels of accuracy over classical methodsand is free from other interferences. The accuracy levels of themethod developed were checked using reference standards.