Yttrium extraction from chloride solution with a synergistic system of 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester and bis(2,4,4-trimethylpentyl) phosphinic acid

• The maximum synergistic effect was obtained at the molar ratio of 1:1.
• The extracted complex by the synergistic system was determined to be Y(HB2)(HA2)2.
• One chloride ion was involved in the extraction with HEHEHP or Cyanex272 system.
• No effect of the chloride was found with the synergistic system.
• The IR spectrum was applied to verify the cation exchange mechanism.

The extraction of yttrium from chloride medium with a mixture of 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester (HEHEHP, H2A2) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272, H2B2) in kerosene has been studied. The extraction mechanism was determined by the methods of slope analysis and constant mole. The maximum synergistic enhancement factor of 2.94 was obtained at a HEHEHP/Cyanex272 molar ratio of 1:1. It was found that yttrium was extracted with the synergistic system in the form of Y(HB2)(HA2)2. It is very different from the extraction forms of YH2ClA4 and YH2ClB4 when extracted by HEHEHP and Cyanex272 alone system, respectively. The effects of chloride ion on the yttrium extraction were also studied and the extracted complexes in the organic solution were determined by the infrared spectrum method. It was confirmed that the extraction was via a cation exchange mechanism.