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

摘要

Tri-hydrate alumina or gibbsite (Al_2O_3.3H_2O) content in bauxiternis a fundamental quality parameter in the Bayer alumina processrnusing low temperature digestion. Classical techniques availablernfor its estimation are time consuming and prone to standard andrnnon-standard sources of error. Extensive studies on analysis ofrnsamples from Central Indian bauxite sources usingrnthermogravimetry over varied temperature ranges and comparisonrnwith that of the data obtained from classical techniques, havernrevealed that loss of molecular water at different temperatures inrnthermo-gravimetry provides a meaningful tool to correlate withrntri-hydrate alumina content by applying relevant correction factorsrnderived from the experimental data at different concentrations ofrntri-hydrate alumina. The studies also have found that the thermogravimetricrnanalysis can be used as a very fast and dependablerntechnique with higher levels of accuracy over classical methodsrnand is free from other interferences. The accuracy levels of thernmethod developed were checked using reference standards.