Volume 57 (2017) Issue 10 Pages 1670-1676
Many studies have been conducted over the last 50 years or more to clarify the dissolution behavior of lime in slag. In this paper, the previous studies on enhancing the dissolution of lime are reviewed. The research subject is divided into industrial tests to verify the new technology, and laboratory tests to clarify the dissolution mechanism. To enhance the dissolution, the only feasible measure is to increase the interfacial area. For this purpose, various methods to increase surface area have been tried, including the decrease in lime size; powder blowing or injection; controlling the calcination conditions; and application of a pre-melted flux. Among them, powder blowing and the reuse of the refining slag are the most effective measures. For fundamental experiments, the immersion of a rotation rod in the slag, immersion of lime cube with a circular rotating rod, and the addition of lime to the slag under gas bubbling have been conducted. The mechanism and rate-controlling step of lime dissolution have become clear: the destruction of the dicalcium silicate layer is important to promote the dissolution of lime. Stirring-promoted fluid flow and the formation of CO2 inside of the quick lime are proposed as mechanisms of the destruction.