α-Branched Tertiary Carboxylic Acid Hydrazides as Extractants of Rare-Earth Metal Ions from Sulfate Media

Derivatives of hydrazine and α-branched tertiary carboxylic acids of fractions C 10 and C 15 –C 19 : 1,2-diacylhydrazines C 10 , hydrazides C 15 –C 19 , N ′, N -dimethylhydrazides C 15 –C 19 , N ′, N ′-dimethylhydrazides C 10 and hydrazides C 10 in the form of 0.1–0.5 M solutions in kerosene were tested as extractants of lanthanide ions Y, La, Ce, Sm, Er, and Yb in acidic aqueous media. The best extraction properties were exhibited by hydrazide C 15 –C 19 . The conditions and the number of stages of the extraction (from solutions containing 0.5 M H 2 SO 4 ) and stripping (stripping agent 5 M HCl) were determined using La 3+ as an example, until the stripping was saturated (up to 43 g L –1 La 3+ ). The distribution constants ( D ) and separation (β) were calculated for the listed lanthanides.