A novel approach to alkali pug bake for the extraction of rare earth elements from monazite concentrate

Abstract

Background Rare earth elements (REEs) play an important role in many technological advances in the modern world. With applications including hydrogen cars, computer hard drives and wind turbines, REEs are needed in numerous highly technical applications and will be needed more in the future. Monazite and bastnäsite are the two most essential sources of REEs. Bastnäsite is a fluorocarbonate mineral, but monazite is a phosphate mineral, making it much more difficult to decompose. Its stable structure can only be broken down under extreme extraction conditions. A common method to accomplish this has been through the use of sodium hydroxide at high temperatures and extended baking times. However, substituting potassium hydroxide for sodium hydroxide could potentially be a more economically favorable method. The sodium hydroxide method currently in practice produces sodium phosphate that can be sold as a fertilizer (Panda et al., 2014). However, the potassium hydroxide method would produce potassium phosphate, which would be a more effective and valuable fertilizer (Val’kov, et al., 2010).