Utilisation of local raw materials and mine waste to manufacture cement in the Northwest Territories, Canada

Currently, all the cement consumed in the Northwest Territories (NWT), Canada, is imported from other provinces (e.g. Alberta) by long-distance (∼1800 km) freight truck. Transporting cement over long distances not only raises its cost, but also results in a higher carbon footprint. Producing cement locally is therefore a potential low carbon and economic solution for the local industry. However, it is unknown if the local raw materials are suitable for cement manufacture, and there is a lack of a critical raw material – iron ore – for cement manufacturing. However, instead of iron ore, there are iron-rich tailings from a local rare earth element (REE) mine. Towards a low carbon and circular economy, the use of local raw materials (i.e. limestone, clay and gypsum) and mine waste (REE tailings) to manufacture cement in the NWT was explored and the first bag of cement in the history of the NWT was produced. Concrete samples made with the NWT cement achieved strength comparable to that of concrete based on commercial ordinary Portland cement. In addition, it was estimated that locally producing cement in the NWT has the potential to reduce carbon dioxide emissions by 3.0–61.7% as compared with importing cement from other provinces.