Production of HREE Carbonate from the Lofdal HREE Flotation Concentrate Using a Simplified Hydrometallurgical Flowsheet

This chapter delves into the optimization of a hydrometallurgical process for producing high-grade heavy rare earth carbonate from the Lofdal deposit's flotation concentrate. The focus is on optimizing the acid bake process, particularly the temperature and sulfation time, to maximize heavy rare earth extraction while minimizing iron extraction. The text also explores a two-stage impurity removal process using magnesium carbonate, which effectively removes thorium, scandium, iron, aluminum, and some uranium with minimal heavy rare earth losses. Additionally, the chapter discusses the use of ion exchange to remove uranium and the implementation of a mini pilot plant for rare earth carbonate precipitation. The results show that the simplified process can produce a high-grade heavy rare earth carbonate product with typical impurity levels. The chapter concludes with a summary of the key findings and the potential benefits of this simplified process.