Abstract:e disposal of gold ore tailings (GTs) has been a very difficult problem for a long time. us, this study explored a new approach to the management of GTs by preparing Portland cement. Physical properties, reaction mechanisms, and hydration product types of cement prepared with GTs (C-GTs) and ordinary Portland cement (C-SS) were compared. X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscope energy-dispersive spectroscopy (SEM-EDS) analysis techniques were used to study the mineralog… Show more
“…X-ray diffraction (XRD) analysis indicated that the hydration products of cement with GT were identical to those observed for cement without GT. The lack of detection of any diffraction peaks for C-S-H was attributed to the poor crystallization and amorphous properties of the C-S-H gels [97,114]. Based on Table 7, it was observed that the addition of 5% GT achieved the highest strength while further addition of GT caused a significant decrease in strength.…”
Section: Mine Tailingsmentioning
confidence: 99%
“…Meanwhile, other researchers [113] suggested that the tailings should only pass through a 45 µm sieve. Wang et al [97] produced OPC clinker using gold mine tailings (GT) as a substitute for natural sandstone. The burnability analysis indicated that the GT had high reactivity.…”
Alternative to traditional concrete, sustainable concrete reduces cement content, waste management issues, and CO2 emissions. To achieve sustainable concrete, waste materials can be used as supplementary cementitious materials (SCMs) to partially replace cement. Fly ash, ground-granulated blast furnace slag, and silica fume have been heavily studied as SCMs. However, due to the retirement of coal-fired power plants and switching to renewable energy, existing SCMs are losing their dominance. With SCMs becoming more widely accepted as partial cement substitutes, there is fear that the current supply will not meet future demand. As a result, researchers have been looking for alternative SCMs. The circular economy can be achieved by reusing non-hazardous construction and demolition materials, timber, and metal/steel production waste as SCMs. This article discusses emerging SCMs, reactivity evaluation methods, their limitations, and treatment methods that may improve reactivity. Emerging SCMs can replace existing SCMs in quantity, but their supply to cement factories and low reactivity due to stable crystallinity hinders their use. Among treatment methods, particle size reduction effectively enhances reactivity; however, very fine SCM may increase the overall water demand due to the large surface area. Decades-old reactivity evaluation methods have relatively weak correlations and thus misreport the reactivity of SCMs. Newer R3 models, such as calorimetry and bound water, give the best correlations (R ≥ 0.85) for 28-day relative strength and better performance. Additionally, more concrete testing with emerging SCMs under different durability and environmental protection conditions is required and life cycle assessments are needed to determine their regional environmental impact.
“…X-ray diffraction (XRD) analysis indicated that the hydration products of cement with GT were identical to those observed for cement without GT. The lack of detection of any diffraction peaks for C-S-H was attributed to the poor crystallization and amorphous properties of the C-S-H gels [97,114]. Based on Table 7, it was observed that the addition of 5% GT achieved the highest strength while further addition of GT caused a significant decrease in strength.…”
Section: Mine Tailingsmentioning
confidence: 99%
“…Meanwhile, other researchers [113] suggested that the tailings should only pass through a 45 µm sieve. Wang et al [97] produced OPC clinker using gold mine tailings (GT) as a substitute for natural sandstone. The burnability analysis indicated that the GT had high reactivity.…”
Alternative to traditional concrete, sustainable concrete reduces cement content, waste management issues, and CO2 emissions. To achieve sustainable concrete, waste materials can be used as supplementary cementitious materials (SCMs) to partially replace cement. Fly ash, ground-granulated blast furnace slag, and silica fume have been heavily studied as SCMs. However, due to the retirement of coal-fired power plants and switching to renewable energy, existing SCMs are losing their dominance. With SCMs becoming more widely accepted as partial cement substitutes, there is fear that the current supply will not meet future demand. As a result, researchers have been looking for alternative SCMs. The circular economy can be achieved by reusing non-hazardous construction and demolition materials, timber, and metal/steel production waste as SCMs. This article discusses emerging SCMs, reactivity evaluation methods, their limitations, and treatment methods that may improve reactivity. Emerging SCMs can replace existing SCMs in quantity, but their supply to cement factories and low reactivity due to stable crystallinity hinders their use. Among treatment methods, particle size reduction effectively enhances reactivity; however, very fine SCM may increase the overall water demand due to the large surface area. Decades-old reactivity evaluation methods have relatively weak correlations and thus misreport the reactivity of SCMs. Newer R3 models, such as calorimetry and bound water, give the best correlations (R ≥ 0.85) for 28-day relative strength and better performance. Additionally, more concrete testing with emerging SCMs under different durability and environmental protection conditions is required and life cycle assessments are needed to determine their regional environmental impact.
“…It is interesting to visualize options of this type, given that tailings are mainly considered as waste, but have the potential to positively intervene in the circularity of the cement industry by promoting the reduction of virgin resource consumption such as limestone, bauxite, clay, sand, and gypsum (Wang, Yao, et al 2019). Cement production is an activity considered as one of the three industrial processes that have the highest environmental impact, together with the use of fossil fuels and the exploitation of land (Andrew 2018).…”
Mining resources have played a leading role in the development of humanity, and the demand for these raw materials is expected to increase in the foreseeable future. In addition, new technologies also require the extraction of new critical materials. These trends pose various challenges as there is a limited supply of natural resources, and standard mining and mineral processing practices are associated with significant environmental impacts, such as waste generation, energy and water consumption, and CO 2 emissions. The circular economy (CE) has recently gained attention as a model to address such a complex scenario. This work analyzes the current efforts towards the application of CE in mineral processing. Although advances have been made, this review shows that the most significant material flows and environmental impacts occur near the production sites, which currently limits the closure of loops. Besides, mining industries are conservative regarding the adoption of new technologies or processing strategies, which is another hindrance to the implementation of the CE. Thus, and with few exceptions, while some sectors are already facing advanced stages of CE (namely, CE 3.0), the mineral processing field struggles to advance from the basic CE requirements (i.e, CE 1.0 to CE 2.0).
“…Earlier studies stated that GOTs can be utilized as partial replacement to the RS [13]. Wang et al [14] studied the physical properties, reaction mechanism, and hydration product types of cement prepared with GOTs.…”
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