Original Article

Comprehensive effects of CaO/Al₂O₃ ratio and electric field on properties and sulfur directional migration of spent refining slag

¹ Anhui Key Laboratory of Low Carbon Metallurgy and Solid Waste Resource Utilization (Anhui University of Technology), Anhui, Ma’anshan 243002, PR China
² School of Metallurgical Engineering, Anhui University of Technology, Anhui, Ma’anshan 243032, PR China

^* e-mail: wuting@ahut.edu.cn
^** e-mail: which@ahut.edu.cn

Received: 8 July 2024
Accepted: 31 October 2024

Abstract

In order to promote the recycling of spent refining slag, the comprehensive effects of CaO/Al₂O₃ ratio and electric field on properties and sulfur directional migration of spent refining slag were investigated at 1480 °C. It was concluded that with the increase of CaO/Al₂O₃ ratio within 1.0–1.8, the slag structure depolymerized and then polymerized, the melting temperature and viscosity decreased and then increased, and the electric conductivity showed an opposite trend, with the turning point corresponded to CaO/Al₂O₃ = 1.2. The voltages application of 2–4 V promoted the sulfur directional migration in slag, and the sulfur content in slag with CaO/Al₂O₃ = 1.2 was significantly lower than that in slag with CaO/Al₂O₃ = 1.8. The sulfur removal time of spent refining slag was preferred to be controlled at 30 min to prevent influences of electrode loss and sulfur removal resistance. To sum up, applying electric field on slag with optical properties can greatly reduce the sulfur content in slag, which was of great significance to realize the efficient recycling of spent refining slag at hot state.