RE: Rare Earth Extraction from phosphoric acid is game changing.20 Apr 2023 07:24
The main problem is the slightly elevated radioactivity of phosphogypsum, which is due to the high activity concentration of 226Ra, while the remaining impurities can be extracted relatively easily, for example by using phase transformations between different kinds of calcium sulfate hydrate and filtering the obtained solution. Traditional technologies of purification of phosphogypsum from radium are not effective, because of the similarity of chemical properties of radium sulfate and calcium sulfate salts, when the radioactive salt is isomorphously included in the gypsum crystal lattice (Kovler, 2004).