Influence of Compound Additives on Sulfur Fixing Performance of Sorbent Based on Steel Slag at High Temperatures

Abstract

Steel slag is modified with additives to improve its high-temperature sulfur-fixing performance. The effects of sodium lignosulfonate, NaCl, KNO3 and MnO2 on the sulfur fixing performance of steel slag were explored after the ideal calcium–sulfur ratio of steel slag was established to be 2.5. An orthogonal experiment was used to explore the primary and secondary impacts of different additives on the sulfur fixing efficiency. The optimal factor level combination was identified to be 8% sodium lignosulfonate, 1% NaCl, 5% MnO2, and 7% KNO3, with a maximum sulfur fixing efficiency of 70.81%. According to XRF analysis, the sulfur-fixing effect of steel slag with additives was clearly superior to that of steel slag without additives. According to an XRD analysis, the diffraction peak of sulfur-fixing products of steel slag with additives was significantly improved, resulting in a high-temperature resistant phase that prevented sulfur-fixing products from degrading. According to SEM research, the steel slag with additives produced an interface that was conducive to gas–solid interaction in the sulfur fixation process, and sulfur fixed ash of modified steel slag exhibited the surface morphology of a high temperature resistant phase.