| Summary: | EAF stainless steel slag (EAF slag) is one kind of chromium-bearing metallurgical solid waste, which belongs to alkaline steel slag, and contains a large number of alkaline mineral phases. The carbonation activity of these minerals gives EAF slag the capability to effectively capture CO<sub>2</sub>. In this paper, EAF slag samples with different carbonation degrees were prepared by the slurry-phase accelerated carbonation route. The mineralogical identification analysis was used to qualitatively and semi-quantitatively determine the types and contents of the carbonatable mineral phases in the EAF slag. The sequential leaching test was used to study the chromium leachabilities in EAF slags with different carbonation degrees. The results showed that the main minerals with carbonation activity in EAF slag were Ca<sub>3</sub>Mg(SiO<sub>4</sub>)<sub>2</sub> and Ca<sub>2</sub>SiO<sub>4</sub>, with mass percentages of 56.9% and 23%, respectively. During the carbonation process, Ca<sub>2</sub>SiO<sub>4</sub> was the main reactant and calcite was the main product. As the degree of carbonation increased, the pH of the EAF slags’ leachate gradually decreased while the redox potential (Eh) gradually increased. At the same time, a large amount of Ca<sup>2+</sup> in the EAF slag combined with CO<sub>2</sub> to form slightly soluble calcium carbonate, which led to a significant decrease in the conductivity of the leachate. With the gradual increase in carbonation ratio, the leachability of chromium in the EAF slag first decreased and then increased, and reached its lowest value when the CO<sub>2</sub> uptake ratio was 11.49%.
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