A Study of the Solubility of Hydrated Orthophosphates of Yttrium,Lanthanum,Cerium,and Neodymium in Sulfuric-Phosphoric Acid Solutions at 20deg C

摘要

The solubility of YPO_4 centre dot 2H_2O,LaPO_4 centre dot 1.5H_2O,CePO_4 centre dot 1.5H_2O,and NdPO_4 centre dot H_2O 10-60 wt % in sulfuric-phosphoric acid solutions containing 10-60 wt % H_2SO_4 and 13.8-41.4 H_3PO_4 was studied.The Khibiny apatite concentrate is a promising source of lanthanides.It is mostly processed by the semi-hydrate sulfuric acid technology,with the main part of lanthanides concentrated in the phosphosemihydrate.It has been shown previously that the main part of lanthanides is present in the phosphosemihydrate in the form of hydrated Orthophosphates.The content of yttrium,lanthanum,cerium,and neo-dymium oxides in the sum of lanthanide oxides in the apatite concentrate is about 90 wt %.