Resource utilization of sulfidic copper tailings in calcium aluminate cement: Mechanical property, hydration process and environmental impact

Abstract

Sulfidic copper tailings (STs) is a byproduct generated from mineral processing activities. To address this environmental burden, calcium aluminate cement (CAC) was used to utilize STs as cementitious materials. The influence of STs on the hydration process, mechanical properties and life-cycle assessment of STs blended CAC were investigated. Results show that the initial setting time of the samples is significantly shortened with the presence of STs. Moreover, the addition of STs greatly accelerates cement hydration and promotes the formation of ettringite, which is caused by the dissolution of sulfidic-rich STs. Hence, the hardened cement paste containing 5 wt.% STs with dense microstructure and high elastic modulus is achieved, which enhances the compressive strength for STs blended CAC. From an environmental point of view, the utilization of STs can save energy and reduce CO2 emissions. Such work may provide new insights into the application of sulfidic copper tailings in low-carbon cementitious materials.