Influence of MgO and C/A and cooling system on alumina leaching properties of calcium aluminate slag

Abstract

The influences of the content of MgO and C/A (molar ratio of CaO and Al2O3, excluding CaO in 2CaO • SiO2) and cooling system on alumina leaching properties of calcium aluminate slag were investigated by XRD, laser particle size analyzer and chemical analysis. The results showed that when the temperature of taking the sample out from furnace is 1200°C, the alumina leaching rate is gradually decreased from 82.12% to 51.3% with the content of MgO increasing from 0% to 5%.The leaching rate is gradually increased from 51.3% to 74.74% with C/A increasing from 1.71 to 1.85. The leaching rate is gradually increased with the temperature decreasing under 4~5°C/min of cooling rate. When the temperature is 500°C and C/A is 1.85, the main phases of slags are Ca12Al14O33 and r-Ca2SiO4, the self-disintegrating rate is 94.45%, and the alumina leaching rate is 83.69%. The calcium aluminate slag meets alumina leaching requirements.