Qualitative lead extraction from recycled lead-acid batteries slag

The pyrometallurgic process that the exhausted batteries are submitted for the recovery of metallic lead generates great amount of a by-product called slag. The slag is composed mainly of iron (approximate to 60%) and lead (approximate to 6%), and this residue cannot be disposed in conventional landfill due to the high lead content. This work presents a new methodology for the extraction of lead from slag, based on the complexing effect of EDTA, a chelating ligand that has the ability to solubilize several heavy metals. As the iron (Fe2+/Fe3+) have a formation's constant with EDTA higher than the lead and is present in high concentrations in the samples, the fluoride ion (F-) was employed to mask the iron ions. The tests were carried out in a qualitative way, confirming the lead extraction by the formation of a yellow precipitate of lead iodide. (C) 2009 Elsevier B.V. All rights reserved.