METHOD FOR EXTRACTING LANTHANIDES FROM PHOSPHORIC ACID Russian patent published in 2008 - IPC C01F17/00 C01B25/237 

FIELD: chemistry.

SUBSTANCE: invention pertains to precipitation methods of separating a concentrate of lanthanides from wet-process phosphoric acid, containing calcium and other impurity components, obtained in a dihydrate process of sulphuric decomposition of apatite concentrate, and can be used in the chemical industry. Sulphuric acid at 65 - 80°C is added to phosphoric acid with concentration of 3806-44.0 wt % and containing up to 20 g/l of CaO. The process takes place in two stages. At the first stage, sulphuric acid is added such that its concentration in phosphoric acid is maintained at 2-3 wt % with formation of a primary residue, containing mainly calcium sulphate, which is separated. At the second stage, sulphuric acid is added such that its concentration in phosphoric acid is maintained at 10-15 wt % with formation and separation of a secondary residue, rich in sulphates of lanthanides. The technical outcome lies in obtaining from wet-process phosphoric acid a concentrate of lanthanide sulphates with content of up to 22.5 wt % in terms of ΣLn₂O₃ with high degree of extraction (74.4-95.7%) of lanthanides in the concentrate and reduction of power input of the process. Increased content of lanthanides in the concentrate and their presence in sulphate form simplifies further processing of concentrates and greatly reduces the size of the used equipment.

EFFECT: obtaining concentrate of sulphates of lanthanides with high degree of extraction of lanthanides and lower power input of process.

3 cl, 3 ex