L. Fortin, A. Pucci
Rio Tinto,
Canada
Keywords: gallium, bayer liquor, extraction
Summary:
Low-purity (99% to 99.99%) primary gallium, the precursor feed to high purity Gallium refining, production worldwide comes mostly as a by-product from the bauxite refining processes and to a lesser degree from zinc refining. Current primary gallium production is between 210 and 420 tons per year , of which 97% comes from China. Based on current bauxite and zinc refining capacities, the maximum potential production shall be in the range of 774 tons per year , of which China would account for 84%. The bulk of the current production comes from China who dominates the market and controls pricing. Gallium use is mainly in the electronic field as a gallium arsenide alloy as well as in the LED manufacturing process. More recently, 5G communication networks and devices have created a new demand for novel gallium nitride alloy which enables much higher component temperatures thus enabling increased processing capacity and data volumes. In this context, Rio Tinto Vaudreuil alumina refinery, in Canada, which processes bauxites that contain gallium is a prospective North American source of the critical metal. During the refining process of alumina, gallium reports into three different streams, two of these streams being insoluble as the gallium will be occluded either onto the hydrate product or the bauxite residues, whereas the third stream is a soluble gallium in the process spent caustic liquor. This soluble gallium can be extracted from the spent liquor using either solvent extraction (practiced since the 1970’s) or more recently using ion exchange resins. In both cases, western world economics of these process do not enable competitive across the cycle operating costs. Our paper will discuss the context, historical work and forward-looking needs, opportunities, and technical challenges to enable the production of this critical resource.