TiO2-doping boosting resource utilization of high-manganese electrolytic manganese residue for superior performance glass-ceramics

Abstract

The technology for the resourceful utilization of electrolytic manganese residue (EMR) in the production of superior performance glass-ceramics has garnered significant interest for its potential to maximize the consumption of waste residues in the Mn metal industry. In this study, utilizing the unique chemical composition of high-Mn EMR, superior performance glass-ceramics were prepared via a melting method, with TiO₂ utilized as a nucleating agent. The influence of the TiO₂ doping amount on the crystalline characteristics, microstructure and properties of the glass-ceramics were systematically evaluated. Additionally, the curing mechanism of Mn in glass-ceramics was scrutinized. The results show that TiO₂ enhances the precipitation of Ca(Ti,Mg,Al) (Si,Al)₂O₆ predominant crystalline phase in the glass-ceramics. This phase transitions from a spherical to an interlocking and dense dendritic morphology. The glass-ceramics containing 10 wt% TiO₂, which was heat-treated by nucleation at 750 °C for 2 h followed by crystallization at 900 °C for 3 h, exhibits enhanced mechanical properties and chemical stability. Its bending strength exceeds 40 MPa, with a water absorption of 0.11 %. Additionally, the acid resistance of glass-ceramics is rated at higher than 97 %, while the alkali resistance is over 99.7 %. Notably, the superior performance in Mn leaching toxicity is achieved in T10 (1.39 mg/L), which is attributable to the fact that Mn is physically coating between the crystalline and glassy phases. This technology has the potential to address the issue of heavy metal release from EMR, and provides a theoretical foundation for the industrial production path of glass-ceramics from high-Mn EMR.