Solvent Extraction Separation of Silver(I) and Zinc(II) from Nitrate Leach Solution of Spent Silver Oxide Batteries with D2EHPA

Abstract

In this study, separation of silver(I) and zinc(II) from nitrate leach solution of spent silver oxide batteries were carried out by extraction and selective stripping. Di-(2-ethylhexyl) phosphoric acid (D2EHPA) was used to extract Zn(II) and Ag(I) in the equilibrium pH range of 0.99–1.34. The extraction of Zn(II) was more affected by the pH value than that of Ag(I). Zn(II) and Ag(I) loaded in D2EHPA was separated by selective stripping with a mixture of 0.01 mol/dm³ nitric acid and 1 mol/dm³ thiourea and 0.5 mol/dm³ nitric acid for Ag(I) and Zn(II), sequentially. A process flowsheet for the separation and recovery of Zn(II) and Ag(I) from the nitrate leach solution of spent silver oxide batteries was proposed.

Fig. 10 Process flow sheet for the separation of Ag(I) and Zn(II) from nitrate leaching solution.