Scalable production of smelter-grade alumina from aluminous clay: a critical feedstock for aluminum production

点击翻译按钮获取中文摘要

Context: About 3.5 million tonnes of aluminum are produced annually by using about 7 million tonnes of alumina. North America produces about 13% of global aluminum. Canada is the fourth aluminum producer globally after China, India, and Russia. There are 10 primary aluminum smelters in Canada: one located in Kitimat, British Columbia, and the other nine smelters in Quebec. Smelting grade alumina (SGA) is the feedstock for aluminum production. About 3.5 million tonnes of aluminum are produced annually by using about 7 million tonnes of SGA.Problematic: The majority of commercial alumina is produced through a Bayer-type process whose feedstock is bauxite while there are technical, economic, environmental, and societal concerns associated with this feedstock. For instance, the majority of the world's bauxite reserves are in the southern hemisphere. This reflects the long transportation distance between bauxite reserves and aluminum plants in Canada as well as the dependency of Canada's aluminum industry on foreign imports. Such transportation of bulk material adds to the feedstock cost and carbon footprint. In addition, the quality of bauxite ores has deteriorated over the past deceased due to excessive extractions. Accumulation of toxic red mud ponds and fly ash landfills is another serious challenge in the aluminum industry.Our solution: This reserach, in partnership with AEM Rechnologies Inc., intends to open a new opportunity window to supply SGA sustainably to the aluminum industry in Canada. The SGA will be produced from a raw material that is abundant in Canada. AEM Technologies Inc. is a Canadian company in the province of Quebec. It has developed a technology to produce high-purity alumina (HPA) from this raw material; however, the process is not economically viable for SGA production due to high energy consumption.Objectives: The overall objective is to attain an economic and sustainable production of SGA from the domestic abundant raw material. Thus, we have defined sub-objectives to investigate units of operation, chemical reagents, and kinetic studies to reach a lab-scale process, particularly, to achieve a low enough energy consumption to be as competitive as the incumbent Bayer process. We will also employ a new iterative process scale-up approach to ensure the process is techno-economically promising at a commercial scale. Expected impacts: The proposed research is designed to output a new profitable process for producing SGA with AEM's raw material at an industrial scale. The outcomes of this research will help plan the scale-up of the process in the next steps. The commercial application of the technology will provide engineering and other jobs for Canadians, it will allow the refiners to source their alumina locally (hence, reducing GHG emissions associated with transportation, and dependency on foreign bauxite resources), and it will help clean up toxic red mud ponds and fly ash landfills in Canada. The current global estimate of red mud stockpiled since the inception of the Bayer process is 3-4 billion tonnes. Four undergraduate students, one master's student, and two postdocs will be trained during this project. At least, 5 high-impact journal articles, 3 conference articles, and 3 patents are expected to outcome from this research.