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This project describes the process of recovering of rare earth elements (REE) from phosphogypsum (PG) waste using a novel biolixviant produced by a bacteria strain known as Glucanobacter oxydans and is inspired by novel research occurring at Idaho National Laboratories. This report details design of a plant which has the capacity to produce the biolixiviant through fermentation, use this biolixiviant to leach REE from a solid waste such as PG, and recover the REE in oxide form through crystallization, filtration, and subsequent high temperature decomposition. The plant has the capability of processing nearly 1 million MT of PG a year and yields 286,000 kg of a rare earth oxide (REO) mixture, valued at approximately $9 per kg. As it stands, this process is unprofitable: it has a negative internal rate of return after 15 years of production and has a NPV of negative $147,664,900. In its third year of production, operating at 91% capacity, the plant has a -21.17% ROI. An alternative design is considered where fermentation is cut and H2SO4 is the lixiviant, removing 79% of the original capital necessary to create the plant. Though still negative, the IRR/ROI are much more sensitive to changes in product price, thus opening a potential path to profitability in the near future as prices are expected to increase.
Date Posted: 11 May 2020