Phosphate Decomposition by Alkaline Roasting to Concentrate Rare Earth Elements from Monazite of Bangka Island, Indonesia

The article considers extraction of rare elements from monazite and their leaching. In this study, phosphate decomposition process was conducted using alkaline roasting. The results showed that the phosphate decomposition of monazite from Bangka Island increased with increasing temperature and increasing monazite/NaOH mass ratio. Analysis of the decomposition rate on the basis of shrinking core model revealed that the rate could be appropriately expressed by the equation based on mixed control of diffusion through a residual layer and surface chemical reaction.