The Sintering and Leaching of Low-Grade Diasporic Bauxite by the Improved Lime-Sintering Process

摘要

An improved lime-sintering process was developed to produce alumina from low-grade diasporic bauxite in this paper. Both clinkers sintered by the real bauxite and simulated bauxite at 1350°C when the molar ratio of CaO to Al_2O_3 decreased to 1.4 were produced, the alumina leaching rates of which reached over 90% in sodium carbonate liquor. The main phases in the clinkers after sintering are 12CaO·7Al_2O_3, γ-2CaO·SiO_2 and 2CaO·Fe_2O_3. Addition of alkali can decrease the C/A ratio and get a high alumina leaching rate of clinker.