Leaching of lead from spent motorcycle battery in hydrochloric acid. Part II: Solvent extraction studies

Abstract

This work, constituting the second part of acid leaching of total Lead studied the extraction efficiency of Pb (II) by solvent extraction techniques by Dithizone in chloroform. The development of simple hydrometallurgical route for possible recovery of total lead from spent motorcycle battery ash leach liquor in hydrochloric acid solution has been investigated using combination of leaching, cementation, precipitation, solvent extraction and stripping techniques. The influence of extractant concentration on lead extraction and the extraction temperature on the total Lead extraction efficiency were examined. An extraction efficiency of 98% total Pb(II) was obtained by 0.01 mol/L Dithizone in chloroform at pH 8.3 from the initial 10g/L motorcycle ash leach liquor containing mainly 763.1 mg/L Pb, 4.3 mg/L Zn (10.7 mg/L after cementation) and 28.8mg/L Fe. Other constituents such as Cu, Mn, Ca and As whose concentrations in each case are less than 2mg/L after leaching, were first separated by cementation with zinc granules, followed by the total Iron removal by precipitating with 4mol/L ammoniacal solution to a pH 3.5 at 25±2 0C. Stripping of 98% total Pb(II) from dithizone extract by 0.1 mol/L hydrochloric acid solution was achieved. The values of thermodynamic data obtained on total Pb(II) extraction showed that the extraction by 0.01 mol/L Dithizone in chloroform is thermodynamically favourable. Finally, a simple hydrometallurgical scheme for the operational procedures for the extraction of total Pb(II) from the spent motorcycle ash liquor was presented.