Recycling of solid wastes ferrochromium slag for preparation of eco-friendly high-strength spinel–corundum ceramics

Ferrochromium slag is a by-product of thermal reduction of aluminium obtained during the production of ferrochrome, which are generally considered as solid wastes to be difficult to use effectively. Spinel–corundum ceramics were prepared from ferrochromium slag and bauxite in this study. Sintering behavior of spinel–corundum ceramics was preliminary analyzed. Moreover, obtained high-strength ceramics by modifying the liquid phase process through pyrolusite addition in ceramic system. Spinel–corundum ceramic performance of flexural strength was reached a maximum of 177.7 MP sintered at 1320 °C. In addition, almost no chromium was detected in the ceramic leachate. The mechanism of solidification of chromium ions in sintered ceramics was further studied. Finally, ceramic proppants were successfully prepared with high-strength spinel-corundum ceramics. At the best sintering temperature of 1320 °C, the performances were 5.08% of breakage ratio under 52 MPa and 3.03 g/cm3 of apparent density. The use of ferrochrome slag to prepare high-strength ceramics will be one of the effective ways to utilize ferrochrome slag. •The study provides a feasible way for the effective utilization of ferrochrome slag.•The sintering process of spinel-corundum ceramics is liquid phase sintering.•Pyrolusite promotes the production of liquid phase in the ceramic system.•The flexural strength of spinel-corundum ceramics reached 177.7 MPa.•The breakage ratio of ceramic proppants was only 5.08% under 52 MPa.