Crystallization, structure-property evolution, and solidification of heavy metals of glass-ceramics based on copper tailing/coal slag/red mud

Abstract

The Dexing copper tailing (DCT), Coal slag (CS) and Red mud (RM) were used to prepare a solid waste-derived glass-ceramics. The result shows that the stable base glass can be formed when DCT/CS/RM mass ration is 35/25/40. Different crystallization temperatures (780∼980 ℃) were implemented on the base glass, and found that the glass-ceramics with Ca(Mg_0.5Al_0.5)((Si_1.5Al_0.5)O₆) as the main crystal phase can be synthesized, whose bulk density, water absorption, Vickers hardness, bending strength, acid/alkali-resistance are in the range of 2.747∼2.887 g/cm³, 0.010∼0.027 %, 6.65∼8.24 GPa, 33.89∼118.53 MPa, 67.77∼99.97/97.85∼99.98 %, respectively. Especially, the GC880 not only shows the best properties (bulk density: 2.87 g/cm³; water absorption: 0.018 %; Vickers hardness: 6.96 GPa; bending strength: 118.53 MPa; acid/alkali-resistance: 99.34/99.97 %), but also has an solidification effect on heavy metal ions (Cr³⁺/Mn²⁺/Fe³⁺/Cu²⁺/Ni²⁺), wherein the leaching concentration reduction rates of Mn²⁺ and Fe³⁺ are over 97 %, which has the potential to be applied in decorative glass-ceramics.