Extraction of lanthanides from the Brazilian phosphate ores
Résumé
The phosphate ore of Angico dos Dias (Caracol, Brazil) is composed of quartz, fluorapatite and mixed aggregates of kaolinite, Al-phosphates of the crandallite-group (with Ba, Sr and Ca), iron oxides/hydroxides, potassic feldspaths, titanite and magnetite with or without associated ilmenite. The principal rare earth elements (REE) bearing-mineral is monazite (64%) and to a lesser extent apatite (up to 1%). The monazite is characterized by a fine granulometry and occurs as inclusions either in apatite grains or in the mixed aggregates. Monazite is always bright contrasting with the light-grey Fe or Fe/Ti minerals. Agglomerates of several minerals are presents in high quantities.