Sustainable System for Mineral Beneficiation

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Ores are rocks or sediments that are the source of valuable metals and minerals. Ores must be processed to recover metals and minerals, and many metals are first concentrated in mineral form, before being chemically converted to metallic form. Extraction and concentration of minerals from ores consumes an immense amount of water. For instance, 1.27 million tons of copper were produced from US mines in 2017, and this required roughly half a billion tons of water. Although metal recycling is on the rise, it has not offset the continued increase of metal use with time. Most domestic ore deposits are found in arid regions of the country (Utah, Arizona, New Mexico and Nevada), and high water demand for mineral extraction exacerbates water supply concerns for urban centers. To address the high water demand, this project will develop engineered microspheres with surface chemistry tailored to adhere to dry mineral particles in order to reduce the water consumption of mineral extraction. The research will focus on exploiting the strength of adhesion between chemically modified glass microspheres relative to polystyrene controls. Glass is representative of silicate minerals, which are the most ubiquitous type of minerals found in ore bodies. The glass microspheres will be chemically modified to create superhydrophobic or superhydrophilic surfaces that adhere to small mineral particles. Mineral adherence to the model glass microspheres, as a function of particle size, will be tested and modeled via a combination of drop tests, spectroscopy, and image analysis. Adhesive surface energy will be quantified using van Oss-Good-Chaudhury and Hansen solubility parameter approaches. The adhesion results will be used to develop and validate a predictive, computational model to enable process design and optimize relevant process parameters. Successful completion of the project will enable more sustainable recovery of minerals with less water consumption and reduced environmental impact. The research will be incorporated into undergraduate design projects, and graduate courses on modeling, and will support the hands-on research training of two graduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.