Extraction of Zn, Mn and Co from Zn-Mn-Co-Cd-Ni containing solution using D۲EHPA, CYANEX® ۲۷۲ and CYANEX® ۳۰۲

Effects of pH, D۲EHPA, Cyanex® ۳۰۲ and Cyanex® ۲۷۲ 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® ۳۰۲ 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® ۲۷۲ shifted all three curves to the right. The most suitable extractant for separation of zinc from manganese was therefore ۰.۳–۰.۳ mixture of D۲EHPA with Cyanex® ۳۰۲ and for separation of manganese from cobalt was sole D۲EHPA. The stoichiometric coefficient for the extraction reaction of zinc (whether using pure D۲EHPA or a mixture made of D۲EHPA with Cyanex® ۲۷۲ or Cyanex® ۳۰۲) was ۳. It varied from ۴ to ۵ for manganese, when the quantity of Cyanex® ۳۰۲ dissolved in D۲EHPA increased from ۰ to ۱۰۰%. 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 ۰.۶M D۲EHPA extractant could recover zinc and a scrubbing reaction with organic:aqueous (O:A) ratio of ۲۰:۱ could wash-out cadmium from the raffinate. In the second stage, the leaching residue was treated with ۰.۶M D۲EHPA for recovery of manganese. This stage was then followed by a one-stage scrubbing of cobalt with O:A ratio of ۲۰:۱.

Keywords:

Solvent extraction , Zn , Mn , CO , Cd , Ni , D۲EHPA , CYANEX® ۲۷۲ , CYANEX® ۳۰۲ , Stoichiometric Coefficient , Organic Aqueous Solution