EXTRACTION OF ZN, MN AND CO FROM ZN-MN-CO-CD-NI CONTAINING SOLUTION USING D2EHPA, CYANEX® 272 AND CYANEX® 302

Effects of ph, d2ehpa, cyanex® 302 and cyanex® 272 on extractions of zinc, manganese and cobalt from a zn-mn-co-cd-ni containing solution was comprehensively investigated at the room temperature. the addition of cyanex® 302 indicated a left-shifting-effect on the extraction curve of zinc, a right-shifting-effect on the extraction curve of manganese and no effect on the extraction of cobalt. the addition of cyanex® 272 shifted all three curves to the right. the most suitable extractant for separation of zinc from manganese was therefore 0.3–0.3 mixture of d2ehpa with cyanex® 302 and for separation of manganese from cobalt was sole d2ehpa. the stoichiometric coefficient for the extraction reaction of zinc (whether using pure d2ehpa or a mixture made of d2ehpa with cyanex® 272 or cyanex® 302) was 3. it varied from 4 to 5 for manganese, when the quantity of cyanex® 302 dissolved in d2ehpa increased from 0 to 100%. utilizing the above results, a two stage leaching was devised to recover zinc, manganese and cobalt from a complex solution. at the first stage, a 0.6m d2ehpa extractant could recover zinc and a scrubbing reaction with organic:aqueous (o:a) ratio of 20:1 could wash-out cadmium from the raffinate. in the second stage, the leaching residue was treated with 0.6m d2ehpa for recovery of manganese. this stage was then followed by a one-stage scrubbing of cobalt with o:a ratio of 20:1