Herein, stainless-steel slag was used to prepare glass–ceramics. The effects of the MgO content on the occurrence, distribution state, and migration behavior of Cr in glass–ceramics as well as glass properties were systematically studied. Results revealed that in the nucleation stage, the number of Cr-spinel (Cr spinel) nanocrystals initially increased and then decreased with the increasing MgO content. In the crystallization stage, the diopside crystal phase considered Cr-spinel nanocrystals as heterogeneous nuclei, which gradually nucleated and grew. Transmission electron microscopy and X-ray photoelectron spectroscopy analyses showed that part of Cr in the spinel migrated into the diopside lattice and some other parts remained in the Cr spinel wrapped by the diopside. Cr in the glass phase also diffused and migrated into the diopside lattice with the formation of diopside crystals. When the MgO content was 12.3 wt.%, 97.33 wt.% of the total amount of Cr was observed in the diopside crystal phase and the leaching concentration of Cr in the glass–ceramics was only 0.006 mg/L. The compressive strength of the glass–ceramics was 261.7 MPa, and the Vickers hardness was 1007.7 HV. The research results provide theoretical and technical support for strengthening Cr fixation and realizing harmless and high-value utilization of stainless-steel slag

Keywords: Stainless-steel slag, Glass–ceramics, Cr, Migration–distribution, Performance