Résumé
Slags are a potent source of Ca2+ cations for CO2 mineralization reactions. Although studies have been performed to characterize the effects of processing conditions on slag dissolution rates, systematic analyses of the mineralogical controls that affect multicomponent dissolution kinetics and associated Ca release remain sparse. Here, the aqueous Ca extractability of six different types of crystalline slags: electric arc furnace (EAF), basic oxygen furnace (BOF), air-cooled blast furnace (ac-BF), co-mingled electric arc furnace (cm-EAF), stainless steel (SS), and ladle slag (LS), was quantified for varying particle size, solid-to-liquid ratio, reagent, temperature, and pH conditions. We show that the evolution of dissolved Ca over time can be described by power relationships, indicating temporally decreasing rates of Ca release, wherein the (apparent) rate constants describe extrinsic controls on kinetics. In addition, we clarified that Ca release kinetics in crystalline slags is directly related to its mineralogy, particularly the amounts of Ca-containing silicate, aluminate, carbonate, and oxide minerals, which further have distinct pH-dependent reactivities. The degree of polymerization of Ca silicates, which can be correlated with the slag’s bulk chemical composition, exerts significant control over Ca extraction rates. The outcomes of this study can be applied to optimize, for instance, mineralization carbonation processes involving the use of crystalline Ca-rich alkaline solids in various leaching environments.