Role of self-disintegrating effect produced by decomposition of limestone core on accelerating dissolution of lime in CaO–SiO 2 –FeO x slag

Abstract

The dissolution behaviours of lime, limestone and lime sample with limestone core-lime shell structure in CaO–SiO₂–FeO_x slag were investigated. The results show that dissolution of lime slows down once 2CaO·SiO₂ layer is formed at slag/lime interface. Self-disintegrating effect produced by decomposition of limestone core can accelerate dissolution, but dissolution rate firstly increases, and then decreases with the CaCO₃ content of samples increasing. Limestone must decompose to form lime before dissolution, and too much CO₂ generated by decomposition of limestone bearing 98.9 wt% CaCO₃ blocks the contact between molten slag and lime layer. Thus, limestone hardly dissolves after 60s contacted with molten slag. For lime sample with core–shell structure, the surface of sample is lime layer that can be directly dissolved in molten slag. Meanwhile, self-disintegrating effect produced by decomposition of limestone core enhances slag penetration, and accelerate dissolution. The optimum CaCO₃ content in lime sample is 22.7 wt%.