AN ANALYTICAL SHORTCUT TO ESTIMATE ALUMINA CONTENT BY LOI IN LATERITIC GIBBSITE BAUXITE PROSPECTING

Lateritic gibbsite bauxite is a major type of raw material used for the production of alumina within the Bayer process. The purpose of resources exploration for bauxite is to seek high Al₂O₃, low SiO₂ and other low impurity ores. Laboratories analysing gibbsitic bauxites use XRF or other chemical techniques to measure the quantity of Al₂O₃, SiO₂, Fe₂O₃ and TiO₂, and muffle furnaces to measure LOI. The equipment required for this type of analysis is very expensive, require electricity and clean laboratory conditions which are rarely available in the field where geologists are working. Geological exploration teams are working in jungles and mountainous areas and are regularly a long way from the closest township and they are continuously on the move. Consequently laboratories cannot satisfy the requirements of field geological teams. For this reason a simple and fast methodology for analysing Al₂O₃ content needs to be identified, which can easily be applied in the field. This article discusses the components of LOI in detail, the relationship between LOI and Al₂O₃, and establishes an empirical formula that can be used to relate LOI and Al₂O₃ content. This formula has been proven to provide a reasonable estimation of Al₂O₃ content from LOI measurement. This method can be applied for other field explorations of lateritic gibbsitic type bauxites.