Abstract In this study, a novel process for recovering Cr from Cr-bearing electroplating sludge (ES) was proposed, which involved the desulfurization stage and reduction-smelting stage. In the desulfurization stage, the decomposition of CaSO4 in the ES was promoted by adding a certain amount of carbon. It was found that the desulfurization ratio increased first and then decreased as increasing the C/S (molar ratio) from 0.5 to 2, while it monotonously increased as the temperature was raised. The product with the highest desulfurization ratio (89.71%) and the lowest residual sulfur of ES (0.47 wt%) was obtained when the reaction temperature was 1100 ℃ and C/S was 1.5. The desulfurized ES was then deeply reduced by Si. In this stage, Si reduced Cr2O3 in the ES to metallic Cr and formed a liquid Fe–Cr–Si alloy (ferrosilicochromium). The ferrosilicochromium was separated from the molten slag by gravity, and the recovery ratios of Fe and Cr reached 98.9% and 98.7%, respectively. The carbon and sulfur contents of the prepared ferrosilicochromium were 0.01 and 0.009 wt%, respectively, which reached the requirement of commercial ferrosilicochromium (C?≤?0.02 wt%, S?≤?0.01 wt%). In addition, SiO2 produced from the silicothermic reduction facilitated the vitrification of slag, and the harmless glassy slag was finally obtained.Graphical Abstract
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