Inhaltszusammenfassung

Bauxite represents a key raw material for the production of refractory materials. However, the global availability of refractory-grade bauxite is limited. Elevated iron oxide contents adversely affect the high-temperature stability of refractory products, restricting the acceptable Fe2O3 concentration in bauxite to a maximum of 2 mass-%. Consequently, only a few natural deposits are suitable for direct industrial application. To adress this limitation, the present study investigates the feasi...Bauxite represents a key raw material for the production of refractory materials. However, the global availability of refractory-grade bauxite is limited. Elevated iron oxide contents adversely affect the high-temperature stability of refractory products, restricting the acceptable Fe2O3 concentration in bauxite to a maximum of 2 mass-%. Consequently, only a few natural deposits are suitable for direct industrial application. To adress this limitation, the present study investigates the feasibility of processing high-iron bauxites for refractory use through acid leaching. Systematic leaching experiments with hydrochloric acid were conducted on six distinct bauxite samples. A statistically designed experimental approach was applied to derive individual predictive models capable of identifying optimal leaching parameters. The factors investigated included acid concentration, solid-to-acid ratio, leaching temperature, leaching time, and bauxite grain fraction. Based on these data, a comprehensive methodological framework for bauxite processing was developed, encompassing the relevant factors, applicable paramenter ranges, and evaluation criteria. The results demonstrate that statistically derived, bauxite-specific models can predict optimal process conditions. Structural and mineralogical analyses provided additional insights into the leachability of aluminum- and iron-bearing phases. To enhance process sustainability, the regeneration of the spent acid was also examined. Liquid-liquid extraction achieved over 99% removal of dissolved iron, enabling reuse of the regenerated acid in subsequent leaching cycles.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
4.32 - Materialwissenschaft

DDC Sachgruppe:
Ingenieurwissenschaften