Improving Flotation Performance of Rare Earth Minerals: A Comparison of Collector Adsorption at the Surfaces of Oxides, Carbonates, Phosphates, and Silicates

Abstract

The adsorption of a collector, salicyl hydroxamic acid (SHA), was kinetically examined. Results were used to infer flotation behavior of the four types of rare earth minerals (REMs): oxides (REOs), phosphates (REPs), carbonates (RECs), and silicates (RESs). Synthetic REMs were used to control purity; hence, various rare earth elements (REEs) were studied with a focus on lanthanum, europium, and dysprosium under basic pH conditions to develop an understanding of how mineralogical differences influence SHA adsorption and therefore REM flotation. Major factors such as lanthanide contraction, coordination number, and surface chemistry were used to explain differences. For RESs, silicate polymerization, as determined by Si:O ratios, was also found to be a factor. Results provide insights into optimizing adsorption and therefore improving REM flotation recovery. Challenges associated with floating RESs, and REMs in general, are highlighted. These challenges can be overcome by using collector blends.