Phosphoric acid extraction and rare earth recovery from apatites of the Brazilian phosphatic ores

Fernando Pereira (1, 2, 3) , Essaïd Bilal (1, 4, 5)

1 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
2 GENERIC-ENSMSE - Département Géochimie, environnement, écoulement, réacteurs industriels et cristallisation
3 LMV-ENSMSE - Laboratoire Magmas et Volcans
4 GSE-ENSMSE - Département GéoSciences et Environnement
5 EVS - Environnement, Ville, Société

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.

Keywords: phosphoric acid production; fertilizer industry; rare earth elements recovery; phosphate rock; hydrochloric acid route

Domains: Chemical and Process Engineering; Geochemistry; Global Changes

Fernando Pereira, Essaïd Bilal. Phosphoric acid extraction and rare earth recovery from apatites of the Brazilian phosphatic ores. Romanian Journal of Mineral Deposits, 2012, 85 (2), pp.49-52. ⟨hal-00788958⟩