Non-thermal process for extracting rare earths from bastnaesite by means of mechanochemical treatment

A novel process for extracting rare earths such as Ce, La contained in bastnaesite mineral (ReCO₃F, Re = rare earths) has been developed in this work. This process is composed of three steps. The first step is milling of the mixture of bastnaesite and NaOH powders, forming mechanochemically Re(OH)₃ and Na compounds. The second step is washing of the ground mixture with water, removing the soluble Na compounds. The third step is leaching of the washed powder with HCl or H₂SO₄ solutions at room temperature, extracting the rare earths. The extractive yield of rare earths is improved with an increase in milling time. Furthermore, HCl solution is superior to H₂SO₄ as a leaching medium. In the present work, more than 90% of the rare earths in the bastnaesite sample was extracted by dilute HCl solution from the mixture milled for 120 min.