The carbon mineralization behavior of copper slag and its impact on pozzolanic reactivity

Abstract

The massive discharge of copper slag (CS) has led to serious environmental problems. Carbon mineralization, as a treatment method of solid waste, not only achieves carbon sequestration, but also enhances the pozzolanic activity. In this work, a novel exfoliation aqueous carbonation method combining aqueous carbon mineralization and wet grinding was proposed to evaluate the carbon mineralization behavior of CS at mild temperature and pressure. The results indicated that exfoliation aqueous carbonation exhibited higher mineralization degree than that of classical CO₂ bubbling carbonation. The carbonation products of CS were mainly composed of amorphous carbonate and silica. Elevated carbonation temperature could promote the dissolution of fayalite in CS to enhance the carbon mineralization degree. Carbon mineralization treatment could improve the pozzolanic reactivity of CS and the 28 d strength activity index could reach up to 106.3%. The outcomes could help provide new technology to facilitate the resource utilization of CS.