Phosphoric Acid Extraction and Rare Earth Recovery from Apatites of the Brazilian Phosphatic Ores

Various experiments led in laboratory on the concentrate of Angico dos Dias phosphate allowed us to define the following steps in the process of hydrochloric treatment: 1 – Acidification of the concentrate by HCl at 20% during two hours at ambient temperature (solid/liquid ratio of 40%, agitation speed of 200 rpm). In these conditions, the solubilisation rates of CaO and P2O5 are commonly superior to 95% (around 80% for (REE)2O3) ; 2 – Precipitation, at ambient temperature, of Na2SiF6 after the addition of a sodium salt to the chlorophosphate solution. The precipitate gotten reveal that more than 80% of the fluorides, initially present in the phosphate rock, can be recovered as sodium fluorosilicates ; 3 – Liquid-liquid extraction of the phosphoric acid by the tributylphosphate. The aqueous phase obtained is treated by ammonia so as to precipitate the rare earth elements as a phosphate concentrate. The application of the process practically does not allow the formation of residues or liquids. The (REE) recovery rate of 80% constitutes a valorization source of the proposed process. by extraction, there are two classes of molecular solvents very low, for example the tributylphosphate TBP e chemical composition of the leachate obtained (as major constituents Ca, P and F) is shown in Table . 2. Rem