The Effect of Palygorskite on the Properties of Copper–Nickel Smelting Slag-Based Cementitious Materials

Abstract

The accumulation and pollution of copper–nickel smelting slag (CNSS) and other non-ferrous metal smelting slag have become a global issue and focus on the resource utilization of solid waste. CNSS can be used as a substitute for cement to prepare cementitious materials for mine filling, which has the characteristic of effectively immobilizing heavy metal ions. In order to study the feasibility of CNSS for large-scale consumption and utilization in the field of mine filling, cementitious materials were prepared in this study using copper–nickel smelting slag, cement, and palygorskite. The effects of palygorskite addition and curing time on the mechanical properties and microstructure of cementitious materials based on CNSS have been evaluated in detail. The results showed that the addition of palygorskite positively affected the immobilizing of the cementitious materials with the non-ferrous smelting slag by promoting the early hydration reaction. The strength of cementitious materials reached 23.05 MPa when 1% palygorskite, 50% copper–nickel smelting slag, and 49% cement were used, which meet the standards requirements of the mine-filling cementitious materials. The addition of only 1% palygorskite can improve the ability of cementitious materials to immobilize heavy metals and achieve the economic utilization of solid waste in mining areas.