Atmospheric leaching of rare earth elements from bauxite residue-process modelling and feasibility study

该建议描述了探索从铝土矿渣中常压浸出稀土元素的发展计划。稀土元素是十五个镧系元素加上钇和钪，具有独特的磁性、光谱和催化性能，因此它们是现代社会所依赖的许多绿色和技术先进产品的主要组成部分。对稀土的需求急剧增加，有些被确定为战略物资。这些元素可获得的主要来源有限，而且集中在中国;因此，包括加拿大在内的许多国家已开展活动，以满足它们对这些元素的需求。目前的建议侧重于从力拓生产的铝土矿残渣中回收这些元素。研究的目的是最大限度地提高浸出效率的稀土渣，回收浸出剂，通过去除杂质，并建立一个化学模型来模拟过程。为期一年的交付成果包括：1）使用微波辅助的创新大气浸出工艺; 2）消耗浸出剂的新型回收工艺; 3）AspenPlus中模拟该工艺的工艺模型;以及4）技术经济分析结果。拟议的研究对加拿大人非常有益，因为它将提高加拿大在稀土加工方面的技术优势。此外，它还具有环境效益，因为它有助于处理其他废物流并将其转化为有价值的产品，同时可能减少其对环境的不利影响。它还将帮助加拿大生产商满足对这些材料的需求。此外，顶尖人员将接受这项研究的培训，以在加拿大矿业部门或学术界从事职业生涯。

This proposal describes the development plan for exploring atmospheric leaching of rare earth elements (REEs) from bauxite residue. REEs, fifteen lanthanides plus yttrium and scandium, have unique magnetic, spectroscopic and catalytic properties, so they are the main building block of many green and technologically advanced products relied upon by the modern society. The demand for REEs is increasing sharply, and some are identified as strategic materials. The accessible primary sources for these elements are limited and concentrated in China; hence many countries, including Canada, have initiated activities to satisfy their demand for these elements. The current proposal is focused on the recovery of these elements from bauxite residue, produced by Rio Tinto. The aim of the research is to maximize the leaching efficiency of REEs from the residue, recycle the leaching agent by removing impurities, and develop a chemical model to simulate the process. The one-year deliverables include: 1) an innovative atmospheric leaching process using microwave assistance; 2) a novel recycling process for the consumed leaching agent; 3) a process model in AspenPlus to simulate the process; and 4) techno-economic analysis outcomes. The proposed research is highly beneficial for Canadians, as it will improve Canada's technical edge in processing of REEs. Furthermore, it has environmental benefits; because it helps process an otherwise waste stream and convert that to a valuable product, while potentially reduce its adverse environmental impact. It will also help Canadian producers satisfy their demand for these materials. In additions, top personnel will be trained in this research for careers in the Canadian Minerals sector or academia.