Preparation of glass–ceramics from blast furnace slag and its heavy metal curing properties

High-performance slag glass–ceramics were prepared by melting method using rare earth-containing blast furnace slag as the main raw material and Fe₂O₃ and Cr₂O₃ as composite nucleating agents. The influence of ZnO on the structure and properties of glass–ceramics was studied by changing the addition amount of ZnO. The existence state and solidification mechanism of heavy metals Zn, Mn, Cr and rare earth ions in glass–ceramics were also analyzed simultaneously. The results showed that the high electric field characteristics of Cr ions contributed to the formation of spinel phase, while Zn and Mn ions can enter the spinel crystal by substitution and exist stably. The Zn ions were mainly distributed in the spinel phase and glass phase, and the Zn ions in the glass phase affected the physicochemical properties of glass–ceramics by changing the glass network structure. In addition, the rare earth ions were mainly found in the augite and glass phases. The leaching characteristics of heavy metals in glass–ceramics showed that the leaching concentrations of heavy metals Zn, Mn and Cr ions were much lower than the standard value of hazardous waste leaching toxicity, indicated that glass–ceramics have good curing effects on Zn, Mn and Cr ions.