Properties and heavy metals immobilization mechanism of glass-ceramics derived from lead zinc slag and red mud

Lead and zinc slag (LZS) and red mud (RM) are industrial solid wastes that cannot be directly utilized due to the presence of harmful substances. How to largely and safely utilize LZS and RM is an urgent problem to be solved. Therefore, this study prepared RM-LZS-glass-ceramics (RLZ-GC), and the properties and the heavy metal immobilization mechanism of RLZ-GC were investigated. Under optimal heat treatment conditions-nucleation temperature of 750 degrees C, nucleation time of 2.0 h, crystallization temperature of 860 degrees C, and crystallization time of 1.5 h-the RLZ-GC exhibited a bulk density of 3.45 g center dot cm-3, compressive strength of 267 MPa, Vickers hardness of 897 HV, and acid and alkali resistance exceeding 99.90 %. The results demonstrate that the crystallinity of the crystalline phase can be improved by optimizing the heat treatment conditions to improve the performance of RLZ-GC. The immobilization efficiency of RLZ-GC for Zn exceeded 99.74 %. The mechanism of heavy metal immobilization was that RLZ-GC immobilized Pb and Zn through the immobilization of the glass phase and the formation of Zn-containing crystal phases in the microcrystalline phase. This study is helpful for utilization of RM and LZS, which can promote the application of solid waste in producing glass-ceramics.