Leaching Behavior of Alumina from Smelting Reduction Calcium Aluminate Slag with Sodium Carbonate Solution

Abstract

Leaching behavior of alumina of smelting reduction calcium aluminate slag based on high-iron red mud composition was investigated. Alumina of calcium aluminate slag was leached using sodium carbonate solutions (Na2CO3 abbr., Na2Oc). The effects of Na2Oc concentration, reaction temperature, reaction time, liquid-solid ratio on the leaching rate of alumina were investigated and its leaching kinetics was studied as well. The results show that the optimum conditions of leaching is reaction temperature of 75 °C, Na2Oc concentration of 100 g L−1, reaction time of 100 min, liquid-solid ratio of 4.5:1. The leaching rate of alumina is 83.7% under the optimum conditions. It is found that the leaching process can be satisfactorily represented by fitting with Avrami equation. The apparent activation energy of leaching pro cess and the feature parameter of Avrami equation are determined to be 11,844 kJ mol−1 and 0.0983, respectively, the leaching process is inner-difussion controlled.