SODIUM-SALTS OF D2EHPA, PC-88A AND CYANEX-272 AND THEIR MIXTURES AS EXTRACTANTS FOR COBALT(II)

Extraction of cobalt(II) from an acidic sulphate solution has been studied using sodium salts of D2EHPA, PC-88A and Cyanex-272 in benzene; the corresponding pH(0.5) values are 6.0, 6.25 and 6.6, respectively. The extracted species appear to be CoA(2)(HA)(2). The electronic spectra of the extracted organic phase support the nature of the species extracted. The loading capacity of 0.1 M extractants in benzene has been determined. The influence of NaCl, NaNO3, Na2SO4 and NaSCN on the extraction systems has been investigated. Synergism has been observed with the binary mixture of all the three extractants used. Of the three extractants, sodium salt of Cyanex-272 has been found to be the best synergist and sodium salt of D2EHPA the least.