(198c) Green and Sustainable Processes for Critical Metal Recovery Using Oxalate Chemistry

Green chemistry is the design of energy-efficient chemical processes and products with environmentally benign input materials while preventing waste generation. This presentation will describe sustainable metal extraction processes from three different types of mixed metal oxide materials: spent lithium-ion battery cathodes, bauxite, and ilmenite. Recycling of spent lithium-ion battery cathodes have the potential to meet the growing demand of two critical metals: lithium (Li) and cobalt (Co). The demand for both of these metals are exponentially increasing with the rapid growth in electric vehicles. A green, closed-loop, and sustainable process for recovery of both of these metals from lithium cobalt oxide (LiCoO₂) has been developed utilizing oxalate chemistry. In this process, the recovery and recycle of the aqueous acid through a novel ion-exchange process minimizes waste generation. The Li is separated in the form of lithium carbonate (Li₂CO₃) and the Co is separated either as cobalt oxide (Co₃O₄) or cobalt hydroxide (Co(OH)₂). The oxalate-based process has also been applied for refining of ores such as bauxite and ilmenite and recovery of commercially valuable metals such as aluminum (Al), iron (Fe) and titanium (Ti). These metals can be efficiently separated and recovered in the form of their metal hydroxides. This presentation will cover the experimental and mechanistic details along with a techno-economic analysis of our closed-loop processes with existing technologies.