Aluminum Recovery and Process Optimization from High-Silica Kemiklitepe (Türkiye) Bauxite Ore by the Alkaline Roasting-Water Leaching Method

In this study, an innovative and environmentally friendly alternative method was investigated for aluminum recovery from diasporic bauxite, classified as a critical raw material, without using caustic soda. Within this context, the alkaline roasting–water leaching combination was applied to enhance aluminum recovery from high-silica bauxite ore. Optimization of the process parameters was carried out using Response Surface Methodology (RSM). The effects of key parameters, roasting temperature, milling time, and ball-to-powder/ore ratio (BPR), on Aluminum (Al) dissolution were systematically evaluated through the RSM design. The reliability of the model was confirmed by ANOVA analysis, and the regression results indicated that the coefficient of determination (R²) exceeded 90% for all responses, demonstrating a strong model fit. According to the optimization outcomes, the optimum conditions were determined as a roasting temperature of 919 °C, a milling time of 90 minutes, and a BPR of 23. Water leaching results revealed that aluminum recovery increased by approximately 26% in the ore roasted at 1000 °C compared to the raw (unroasted) ore. Overall, the findings indicate that the alkaline roasting–water leaching method is a promising alternative for processing high-silica bauxite deposits.