METHOD OF PRODUCING COMPLEX-FORMING SORBENT FOR SELECTIVE EXTRACTION OF SUM OF RARE-EARTH METALS Russian patent published in 2019 - IPC C08F8/40 B01J45/00 B01J20/26 B01J20/30 B01J39/18 

FIELD: technological processes.

SUBSTANCE: invention relates to production of sorbents. Disclosed method of preparation involves preliminary preparation of an oligomer mixture by treating ethylenediamine with calcium hypophosphite and formalin in a hydrochloric acid medium followed by formation of spherical granules of sorbent by dispersion of obtained oligomer mixture in medium of oleic acid at high temperature. Produced product spherical granules are washed from residues of dispersion medium with acetone, then with water, alkali and acid. Reaction is carried out in two steps: at first step, oligomer mixture is obtained by reacting initial reagents: aliphatic polyamine, calcium hypophosphite, formalin, hydrochloric acid in molar ratio of 1:0.75:4:5–1:1.25:4:5, respectively, at temperature of 25–35 °C, from which at second stage by dispersing in oleic acid medium at 40–60 °C spherical granules of sorbent are obtained. Temperature is then increased to 70 °C and final holding is carried out at temperature of 100 °C. Time of holding granules at each temperature is 1 hour. Further, the sorbent granules are separated from the dispersion medium.

EFFECT: technical result consists in obtaining a sorbent with high capacitance and selectivity to rare-earth metals, low swelling.

1 cl, 5 ex