Pyroxene Ceramics Fabricated from Tailings via Synergistic Oxidation of Converter Slag and Copper Slag: Sintering Behavior, Microstructure Evolution and Mechanical Performance

Abstract

Converter slag and copper slag represent promising sources for ceramic materials, but their high total iron content leads to waste of iron resources and inferior ceramic performance. To address this issue, we propose a two-step utilization method for converter slag and copper slag, including iron extraction synergistic oxidation and ceramic fabrication for tailings. In this study, the effects of tailings content, sintering temperature, and sintering aid addition on the phase composition, microstructure, physico-mechanical properties, and leaching characteristics of the novel pyroxene-based ceramics were investigated. The results reveal that the ceramics containing 50 wt% tailings present a single pyroxene phase with uniformly dispersed fine closed pores. At a sintering temperature of 1190 °C, the optimized ceramic achieves a water absorption of 0.33% and a flexural strength of 80.5 MPa. Elevating the sintering temperature facilitates the grain growth of pyroxene crystals and the formation of a liquid phase. The addition of sintering aid effectively lowers the sintering temperature and improves the densification degree of ceramic matrices. In addition, the leaching toxicity of the prepared ceramics is well below the standard regulatory limits. This study provides a novel approach for the high-value recycling of tailings.