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Abstract
Discussion Forum (0)
Canada has long been recognized as one of the major mining producers of minerals and metals. Despite this enrichment, the mining sector faces many challenges in terms of its undeniable impacts on the environment. Yet, the mining industry has developed many strategies and technologies to mitigate the footprints of its operations and waste materials. One of the promising technologies that have been used for this purpose is mineral carbonation. Mineral carbonation proves to be an efficient way to contribute to the global effort to reduce anthropogenic CO2 emissions using both mined and wasted silicates. The process is implemented in one of three ways: ambient enhanced weathering, engineered accelerated carbonation, and in-situ geological carbonation. Our project has focused on engineered accelerated carbonation using kimberlite, a diamond mining waste product, collected from Gahcho Kué Diamond Mine in the Northwest Territories, and mined wollastonite from the Saint Lawrence Wollastonite Deposit in Ontario. This project targeted the potential of using kimberlite for sequestering carbon dioxide in a safe, long-term and beneficial way (by making building materials), and utilized the fast weathering wollastonite for comparison. The project was conducted to show that CO2 sequestration and utilization can become a normal part of the mining business and life. Both mild and intensified carbonation methods were performed (incubator, slurry, pressurized reactor, and ball mill reactor), and the effect of the process parameters on the CO2 uptake and mineral conversions were studied. The carbonated samples were analyzed by loss-on-ignition (LOI), calcimetry, and XRD analysis. Results showed that wollastonite (a calcium silicate) is more suitable for carbonation than kimberlite (a hydrated magnesium silicate) when only its capability to capture CO2 is considered. However, the potential of utilizing carbonated kimberlite as a building material was verified, and opens opportunities to avoid the environmental impact of tailings ponds, while covering the processing cost of sequestering CO2. Under mild carbonation conditions, incubator carbonation achieved a maximum difference in LOI300-950°C after 144 h of carbonation of 9.5 wt% for wollastonite, and 0.7 wt% for kimberlite, while the slurry carbonation over a period of 4 h was ineffective (0.2 wt% max.). To improve aqueous carbonation, addition of 0.64 M NaOH and kimberlite heat treatment (610 °C to 650 °C, for 2 h to 4 h) for dehydroxylation were conducted; both strategies slightly improved the carbonation (2.6 wt% max. LOI difference). Intensified slurry carbonation (at 200 °C and 60 bar CO2) led to highest LOI differences of 11.8 wt% and 5.2 wt% for wollastonite and heat-treated kimberlite, while fresh kimberlite carbonated best under ball mill carbonation (2.6 wt% LOI difference). Calcimetry and XRD results were largely in agreement with LOI results. They confirmed the formation of calcium and magnesium carbonates (e.g. calcite and lansfordite), and suggest that aluminosilicates are largely responsible for limiting carbonation conversion of kimberlite. Finally, it is planned to perform additional rigorous analyses of the carbonated materials, a deep study on the particle morphology of ball-milled materials, and an estimation of the processing costs, to accurately estimate the feasibility of technology.
Canada has long been recognized as one of the major mining producers of minerals and metals. Despite this enrichment, the mining sector faces many challenges in terms of its undeniable impacts on the environment. Yet, the mining industry has developed many strategies and technologies to mitigate the footprints of its operations and waste materials. One of the promising technologies that have been used for this purpose is mineral carbonation. Mineral carbonation proves to be an efficient way to contribute to the global effort to reduce anthropogenic CO2 emissions using both mined and wasted silicates. The process is implemented in one of three ways: ambient enhanced weathering, engineered accelerated carbonation, and in-situ geological carbonation. Our project has focused on engineered accelerated carbonation using kimberlite, a diamond mining waste product, collected from Gahcho Kué Diamond Mine in the Northwest Territories, and mined wollastonite from the Saint Lawrence Wollastonite Deposit in Ontario. This project targeted the potential of using kimberlite for sequestering carbon dioxide in a safe, long-term and beneficial way (by making building materials), and utilized the fast weathering wollastonite for comparison. The project was conducted to show that CO2 sequestration and utilization can become a normal part of the mining business and life. Both mild and intensified carbonation methods were performed (incubator, slurry, pressurized reactor, and ball mill reactor), and the effect of the process parameters on the CO2 uptake and mineral conversions were studied. The carbonated samples were analyzed by loss-on-ignition (LOI), calcimetry, and XRD analysis. Results showed that wollastonite (a calcium silicate) is more suitable for carbonation than kimberlite (a hydrated magnesium silicate) when only its capability to capture CO2 is considered. However, the potential of utilizing carbonated kimberlite as a building material was verified, and opens opportunities to avoid the environmental impact of tailings ponds, while covering the processing cost of sequestering CO2. Under mild carbonation conditions, incubator carbonation achieved a maximum difference in LOI300-950°C after 144 h of carbonation of 9.5 wt% for wollastonite, and 0.7 wt% for kimberlite, while the slurry carbonation over a period of 4 h was ineffective (0.2 wt% max.). To improve aqueous carbonation, addition of 0.64 M NaOH and kimberlite heat treatment (610 °C to 650 °C, for 2 h to 4 h) for dehydroxylation were conducted; both strategies slightly improved the carbonation (2.6 wt% max. LOI difference). Intensified slurry carbonation (at 200 °C and 60 bar CO2) led to highest LOI differences of 11.8 wt% and 5.2 wt% for wollastonite and heat-treated kimberlite, while fresh kimberlite carbonated best under ball mill carbonation (2.6 wt% LOI difference). Calcimetry and XRD results were largely in agreement with LOI results. They confirmed the formation of calcium and magnesium carbonates (e.g. calcite and lansfordite), and suggest that aluminosilicates are largely responsible for limiting carbonation conversion of kimberlite. Finally, it is planned to perform additional rigorous analyses of the carbonated materials, a deep study on the particle morphology of ball-milled materials, and an estimation of the processing costs, to accurately estimate the feasibility of technology.
Accelerated Carbonation of Kimberlite Tailings Versus Mined Wollastonite for CO2 Sequestration and Utilization
Salma Chalouati
Abstract
Discussion Forum (0)
Canada has long been recognized as one of the major mining producers of minerals and metals. Despite this enrichment, the mining sector faces many challenges in terms of its undeniable impacts on the environment. Yet, the mining industry has developed many strategies and technologies to mitigate the footprints of its operations and waste materials. One of the promising technologies that have been used for this purpose is mineral carbonation. Mineral carbonation proves to be an efficient way to contribute to the global effort to reduce anthropogenic CO2 emissions using both mined and wasted silicates. The process is implemented in one of three ways: ambient enhanced weathering, engineered accelerated carbonation, and in-situ geological carbonation. Our project has focused on engineered accelerated carbonation using kimberlite, a diamond mining waste product, collected from Gahcho Kué Diamond Mine in the Northwest Territories, and mined wollastonite from the Saint Lawrence Wollastonite Deposit in Ontario. This project targeted the potential of using kimberlite for sequestering carbon dioxide in a safe, long-term and beneficial way (by making building materials), and utilized the fast weathering wollastonite for comparison. The project was conducted to show that CO2 sequestration and utilization can become a normal part of the mining business and life. Both mild and intensified carbonation methods were performed (incubator, slurry, pressurized reactor, and ball mill reactor), and the effect of the process parameters on the CO2 uptake and mineral conversions were studied. The carbonated samples were analyzed by loss-on-ignition (LOI), calcimetry, and XRD analysis. Results showed that wollastonite (a calcium silicate) is more suitable for carbonation than kimberlite (a hydrated magnesium silicate) when only its capability to capture CO2 is considered. However, the potential of utilizing carbonated kimberlite as a building material was verified, and opens opportunities to avoid the environmental impact of tailings ponds, while covering the processing cost of sequestering CO2. Under mild carbonation conditions, incubator carbonation achieved a maximum difference in LOI300-950°C after 144 h of carbonation of 9.5 wt% for wollastonite, and 0.7 wt% for kimberlite, while the slurry carbonation over a period of 4 h was ineffective (0.2 wt% max.). To improve aqueous carbonation, addition of 0.64 M NaOH and kimberlite heat treatment (610 °C to 650 °C, for 2 h to 4 h) for dehydroxylation were conducted; both strategies slightly improved the carbonation (2.6 wt% max. LOI difference). Intensified slurry carbonation (at 200 °C and 60 bar CO2) led to highest LOI differences of 11.8 wt% and 5.2 wt% for wollastonite and heat-treated kimberlite, while fresh kimberlite carbonated best under ball mill carbonation (2.6 wt% LOI difference). Calcimetry and XRD results were largely in agreement with LOI results. They confirmed the formation of calcium and magnesium carbonates (e.g. calcite and lansfordite), and suggest that aluminosilicates are largely responsible for limiting carbonation conversion of kimberlite. Finally, it is planned to perform additional rigorous analyses of the carbonated materials, a deep study on the particle morphology of ball-milled materials, and an estimation of the processing costs, to accurately estimate the feasibility of technology.
Canada has long been recognized as one of the major mining producers of minerals and metals. Despite this enrichment, the mining sector faces many challenges in terms of its undeniable impacts on the environment. Yet, the mining industry has developed many strategies and technologies to mitigate the footprints of its operations and waste materials. One of the promising technologies that have been used for this purpose is mineral carbonation. Mineral carbonation proves to be an efficient way to contribute to the global effort to reduce anthropogenic CO2 emissions using both mined and wasted silicates. The process is implemented in one of three ways: ambient enhanced weathering, engineered accelerated carbonation, and in-situ geological carbonation. Our project has focused on engineered accelerated carbonation using kimberlite, a diamond mining waste product, collected from Gahcho Kué Diamond Mine in the Northwest Territories, and mined wollastonite from the Saint Lawrence Wollastonite Deposit in Ontario. This project targeted the potential of using kimberlite for sequestering carbon dioxide in a safe, long-term and beneficial way (by making building materials), and utilized the fast weathering wollastonite for comparison. The project was conducted to show that CO2 sequestration and utilization can become a normal part of the mining business and life. Both mild and intensified carbonation methods were performed (incubator, slurry, pressurized reactor, and ball mill reactor), and the effect of the process parameters on the CO2 uptake and mineral conversions were studied. The carbonated samples were analyzed by loss-on-ignition (LOI), calcimetry, and XRD analysis. Results showed that wollastonite (a calcium silicate) is more suitable for carbonation than kimberlite (a hydrated magnesium silicate) when only its capability to capture CO2 is considered. However, the potential of utilizing carbonated kimberlite as a building material was verified, and opens opportunities to avoid the environmental impact of tailings ponds, while covering the processing cost of sequestering CO2. Under mild carbonation conditions, incubator carbonation achieved a maximum difference in LOI300-950°C after 144 h of carbonation of 9.5 wt% for wollastonite, and 0.7 wt% for kimberlite, while the slurry carbonation over a period of 4 h was ineffective (0.2 wt% max.). To improve aqueous carbonation, addition of 0.64 M NaOH and kimberlite heat treatment (610 °C to 650 °C, for 2 h to 4 h) for dehydroxylation were conducted; both strategies slightly improved the carbonation (2.6 wt% max. LOI difference). Intensified slurry carbonation (at 200 °C and 60 bar CO2) led to highest LOI differences of 11.8 wt% and 5.2 wt% for wollastonite and heat-treated kimberlite, while fresh kimberlite carbonated best under ball mill carbonation (2.6 wt% LOI difference). Calcimetry and XRD results were largely in agreement with LOI results. They confirmed the formation of calcium and magnesium carbonates (e.g. calcite and lansfordite), and suggest that aluminosilicates are largely responsible for limiting carbonation conversion of kimberlite. Finally, it is planned to perform additional rigorous analyses of the carbonated materials, a deep study on the particle morphology of ball-milled materials, and an estimation of the processing costs, to accurately estimate the feasibility of technology.
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