Development of artificial aggregates by using sodium silicate activated copper tailings and slag

Abstract

This study investigated the development of artificial aggregates using copper tailings activated by sodium silicate via granulation. Five different mixes were prepared by incorporating varying amounts of ground granulated blast furnace slag (GGBS) and sodium silicate. The granulation process was performed in a rotating disk granulator, with water sprayed onto the dry mixture to facilitate binding. The resulting aggregates, ranging from 5 to 25 mm in diameter, were cured in a humid environment for 3, 7, and 28 d. The aggregates were then tested for size distribution, oven-dried density, water absorption, crushing strength, and individual-granule strength. Microstructural analysis was conducted using scanning electron microscopy (SEM) and X-ray computed tomography (XCT). The results showed that the addition of GGBS significantly improved the properties of the artificial aggregates, resulting in a higher density, lower water absorption, and increased strength.XCT images revealed a more refined pore structure with smaller and more evenly distributed pores in the GGBS-containing samples. The crushing strength and individual granule strength followed a Weibull distribution, with the GGBS samples exhibiting higher strength values. SEM analysis confirmed the formation of N-A-S-H gel in the GGBS samples, which acted as a binding phase and improved the microstructure. These findings demonstrate the potential of using copper tailings and GGBS to produce sustainable artificial aggregates with enhanced properties for construction applications.