Original Article

Influence of BaO on viscosity and sulfide capacity of CaO-SiO₂-FeO-Al₂O₃-BaO slag

Technical Center of HBIS Group Tangsteel Company, Tangshan Hebei 063000, PR China

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Received: 31 March 2025
Accepted: 12 August 2025

Abstract

The viscosity and sulfide capacity of steel slag with various BaO content was measured. The slag through viscosity and desulfurization equilibrium experiment were analyzed. The network structure, bridging oxygen, and oxygen in molten slag were researched. The corrected optical basicity was calculated and the relationship between corrected optical basicity and sulfide capacity was obtained. The molten slag viscosity showed a decreasing trend with the addition of BaO. The slag sulfide capacity showed an increasing trend with the increase of BaO in slag from 0 to 6%. The logC_S are −4.1605, −4.0984, −4.0570 and −4.0073 with the BaO content at 0%, 2%, 4% and 6%, respectively. The Raman analysis showed that the translations of Q² andQ³ to Q⁰ and Q¹ were promoted by the addition of BaO, indicating that the network structure were simpler. The bridging oxygen was broken by free oxygen ions released from BaO. BaO act as a network modifier in molten slag. The relative fraction of O⁻ and O²⁻ presented an increasing trend with the addition of BaO and that of O⁰ presented a decreasing trend. The X-ray photon-electron spectroscopy (XPS) analysis results indicated that the polymerization degree of slag was reduced and the sulfide capacity of slag was enhanced with the addition of BaO. The XPS results were also consistent with calculated corrected optical basicity result. The relationship between logC_S and corrected optical basicity at 1723 K is logC_S = −28.76 + 37.64Λ^corr.