Viscosity and Structural Characteristics of HIsmelt Chromium-Containing Slag

YJ Zhang and KX Jiao and JL Zhang and XY Fan, METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, 56, 1423-1433 (2025).

DOI: 10.1007/s11663-024-03423-5

HIsmelt process has the potential to directly smelt chromium ore powder, but the CaO-SiO2-MgO-Al2O3-FeO-Cr2O3 slag obtained by smelting is unique, and the viscosity characteristics of the slag system are not clear. Therefore, the viscosity and structure of HIsmelt chromium- containing slag were studied in this paper. The results of viscosity experiments show that increasing the content of Cr2O3 will significantly increase the viscosity of slag. The suitable slag basicity is 1.2, the ratio of MgO/Al2O3 is 0.8, and the content of FeO is 4 pct. The results of Raman spectroscopy show that the addition of Cr2O3 promotes the transformation of low polymerization unit to high polymerization unit, and the degree of polymerization of slag increases, resulting in an increase in viscosity. The addition of MgO shows the opposite effect. The results of molecular dynamics simulation show that with the increase of Cr2O3 content, the proportion of bridging oxygen increases from 64.85 to 71.73 pct, and the proportion of non-bridging oxygen decreases from 31.98 to 25.55 pct. With the increase of MgO/Al2O3, the proportion of bridging oxygen decreased from 66.03 to 62.13 pct, and the proportion of non-bridging oxygen increased from 31.15 to 34.53 pct. Cr3+ are network builders, bridging more O2- and occupying tetrahedral positions, making the silicate network structure more complex, and Mg2+ can depolymerize the silicate network.

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