Abstract
Sulfidic mining waste rock is a side stream from the mining industry with a potential environmental burden. Alkali activation is a promising method for transforming mining waste into construction materials. However, the low reactivity of minerals can be a sizeable challenge in alkali activation. In the present study, the reactivity of waste rock was enhanced by mechanochemical treatment with a LiCl-containing grinding aid. X-ray diffraction (XRD) and diffuse reflectance infrared Fourier transform (DRIFT) analysis were utilized to display the structural alteration of individual minerals. A schematic implication of the grinding mechanism of mica was provided according to the results of transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The alkaline solubility displayed the enhanced chemical reactivity of the waste rock, in which Si and Al solubility increased by roughly 10 times and 40 times, respectively. The amorphization of aluminosilicate is achieved through chemical assisted mechanochemical activation. Sulfidic waste rock, as the sole precursor in alkali activation, achieved a 28-day compressive strength exceeding 10 MPa under ambient curing conditions. The simulation of the upscaled grinding process was conducted via the HSC Chemistry® software with a life-cycle assessment. The results showed that mining waste rock can be a promising candidate for geopolymer production with a lower carbon footprint, compared to traditional Portland cement.Graphical
Highlights
Wastes from mining and mineral processing pose potential environmental and chronic burdens across the world
The tailings are essentially composed of pyrite (80 to 90 wt%), sphalerite, chalcopyrite, galena, and gangue minerals Over a 9-year period from 2010 to 2019, the Neves Corvo operation accumulated 7.3 Mt of waste rock stored at the Cerro do Lobo Tailings Management Facility (TMF) and disposed of 17 Mt of thickened tailings, while 3.1 million tons of oxidized waste rock had been stored in a temporary stockpile by the end of 2019
The goal of this study is to evaluate the environmental performance of alkali-activated binder from waste rock in comparison to that of ordinary Portland cement (OPC)
Summary
Wastes from mining and mineral processing pose potential environmental and chronic burdens across the world. Waste rock is the material generated from excavation of ore, after which sections rich in ore are sent to further ore processing [2]. Mining waste rock is dumped near the mining site or stored in landfills, which can be a potential of pollutants. The utilization of mining wastes is concerning because it poses potential negative impacts on the landscape and local community. Mining waste rock has been used as a secondary raw material in building materials, such as aggregates and raw meals for Portland cement production [3]. Construction materials produced solely with waste rock from sulfidic mining have hardly been studied
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