New method of analyzing bauxites to determine their main components and impurities

This article examines the important problem of finding new, faster, and more efficient methods of analyzing the composition of natural raw materials, especially bauxites – the most important raw material used in the production of alumina. The authors have developed a new method of determining the silica content of bauxites and have used it as a foundation for a new system for analyzing the natural raw materials for their contents of the main components – Al₂O₃, SiO₂, Fe₂O₃, TiO₂, and CNL. The gravimetric method described by GOST 14657.2-96 (ISO 6607-85) to analyze bauxites is laborious and time-consuming. It is based on the precipitation of silicic acid from a hydrochloric acid solution after the bauxite has been decomposed by some method and the subsequent determination of silica from the difference in mass before and after treatment with hydrofluoric acid. The new method is based on the ability of silicon to form volatile silicon tetrafluoride, and the key step is distilling silicon in the bauxite off in the form of SiF₄ without the ore’s preliminary decomposition. The new method costs less than the existing approach, consumes a minimum of reagents, and requires fewer operations than the gravimetric method. The last consideration significantly lessens the effect of the human factor on the results of the analysis, which are at least as accurate as stipulated by the GOST standard.