Kinetic Study on Decomposition and Dissolution of Limestone in Converter Slag

Abstract

The kinetic behaviour of limestone decomposition and dissolution in converter slag at temperatures in the range of 1300–1400 °C was studied. The influence of decomposition reaction on the lime dissolution rate was also investigated. The rate-limiting steps of decomposition and dissolution of limestone in converter slag were determined on the basis of shrinking core hypothesis. The experimental results indicate that a mixed controlling mechanism of chemical reaction and heat conduction through the produced lime layer should be considered for the limestone decomposition in converter slag. The rate-controlling mechanisms of the dissolution of produced lime differ during the various sub-processes. In addition, examination of the lime microstructure at higher slag temperature revealed that cracks are formed in decomposed lime layer; lime dissolution is promoted by molten slag and penetrates through these cracks.