Dissolution behavior of partially calcined limestone with residual CO2 in converter slag

Abstract

Accelerating the dissolution rate of lime in converter slag at the initial stage of steelmaking is conducive to the rapid slagging. In this work, partially calcined limestone with a core–shell structure was prepared, and the dissolution behaviors of lime, partially calcined limestone bearing ∼28 wt% CO2, and limestone in converter slag were studied. The results showed that the formation of 2CaO·SiO2 layer slows down the dissolution of lime. Different from lime, the CO2 bubbles produced by the limestone decomposition could destroy the 2CaO·SiO2 layer and accelerate the dissolutions of limestone and partially calcined limestone. Compared with limestone, the slag temperature drop near the surface is less, and no stagnation stage occurs during the dissolution of partially calcined limestone due to the existence of decomposed lime surface layer. The most rapid dissolution rate and the higher substitution ratio of lime imply that the partially calcined limestone slagging mode would be more promising than limestone and lime.

Keywords

• Partially calcined limestone
• Converter slag
• Dissolution
• 2CaO·SiO2 phase
• CO2 bubbles