Abstract
This study aims to identify the potential of gold mining waste for CO2 sequestration and its utilization for carbon storage in cementitious material. Samples of mine waste were identified from a gold mine for mineralogical and chemical composition analysis using X-ray diffractogram and scanning electron microscopy with energy-dispersive X-ray. Mine waste was utilized in a brick-making process as supplementary cementitious material and as an agent for CO2 capture and storage in bricks. Carbonation curing was incorporated in brick fabrication to estimate CO2 uptake of the brick product. Results indicated that the mine wastes were composed of silicate minerals essential for mineral carbonation such as muscovite and illite (major) and chlorite-serpentine, aerinite, albite and stilpnomelane (moderate/minor phases). The mine wastes were identified as belonging to the highly pozzolanic category, which has a great role in improving the strength properties of brick products. Carbonated minerals served as an additional binder that increased the strength of the product. CO2 uptake of the product was between 0.24% and 0.57% for bricks containing 40–60% of gold mine waste, corresponding to 7.2–17.1 g CO2/brick. Greater performance in terms of compressive strength and water adsorption was observed for bricks with 3 h carbonation curing. The carbonation product was evidenced by strong peaks of calcite and reduced peaks for calcium hydroxide from XRD analysis and was supported by a densified and crystalline microstructure of materials. It has been demonstrated that gold mine waste is a potential feedstock for mineral carbonation, and its utilization for permanent carbon storage in brick making is in line with the concept of CCUS for environmental sustainability.
Highlights
IntroductionIt is clear under the United Nations Sustainable Development Goals (SDG) 13, Climate
It is clear under the United Nations Sustainable Development Goals (SDG) 13, ClimateAction, that climate change is the greatest challenge to sustainable development and requires urgent action to combat it and its impacts
The presence of MgO and Fe2O3 in the samples can be associated with minerals muscovite K(Mg,Fe)3(AlSi3O10)(OH)2, illite (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] and aerinite [(Fe+2,Fe+3,Al)3Mg3(Ca,Na)4(Si13.5Al4.5O42)(OH)6].12H2O, as noted earlier, while Al2O3 is attributable to minerals kaolinite Al2Si2O5(OH)4, chlorite-serpentine (Mg,Al)6(Si,Al)4O10(OH)8, muscovite, illite and aerinite. This shows that the mine wastes have a considerable amount of silicate minerals, which contain important oxide minerals known to be essential for mineral carbonation
Summary
It is clear under the United Nations Sustainable Development Goals (SDG) 13, Climate. That climate change is the greatest challenge to sustainable development and requires urgent action to combat it and its impacts. Climate change is intensified by the introduction of greenhouse gas (GHG) emissions into the atmosphere through various anthropogenic and natural processes. Malaysia has committed to reducing 45% of its GHG emissions by 2030, and its aspiration to achieve net zero carbon emissions by 2050 has been initiated. It has been targeted for CO2 emissions to reach net zero between 2040 and 2060 [3,4]
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