Limestone dissolution and decomposition in steelmaking slag

Based on thermal simulation experiment, SEM analysis and mathematical simulation, limestone dissolution and decomposition mechanism in steelmaking slag were studied. The results showed that limestone decomposition and dissolution happen simultaneously in molten slag, and influence each other. Owing to high-activity lime product and CO2 from limestone decomposition, the dissolution rate of limestone is greater than that of lime under the same conditions in slag, and the calculated activation energy of limestone dissolution is 226.8 kJ mol(-1). On the other hand, as decomposition product lime dissolves into slag, a sloughing-type unreacted shrinking core model was proposed to describe limestone decomposition behaviour in slag. In addition, mathematical simulation results showed that heat transfer is the rate-controlling step for limestone decomposition in slag.