Journal of Hazardous Materials A139 (2007) 430–437 Reactivity of waste generated during lead recycling: An integrated study Arnault Lassin a , Patrice Piantone a,∗ , Andr´ e Burnol a , Franc ¸oise Bod´ enan a , Laurent Chateau b , Catherine Lerouge a , Catherine Crouzet a , Dominique Guyonnet a , Laurent Bailly a a BRGM, 3, avenue C. Guillemin, BP 6008, 45060 Orl´ eans Cedex 2, France b ADEME, 2, square Lafayette, BP 90406, 49004 Angers Cedex 01, France Available online 18 April 2006 Abstract Lead consumption in Europe is 2.054 M tonnes/year, more than 70% of which is produced by recycling and, more specifically, the recycling of car batteries. This industry is jeopardised by the method employed so far, recycling by alkaline fusion, because the treatment produces 200,000 tonnes of toxic and unstable slag. The study presented here attempts to clarify the approach and the combined tools employed (mineralogy, chemistry, leaching, thermodynamics), to construct a coherent physicochemical model of slag behaviour. The model was then used to carry out sensitivity analyses with various landfill scenarios, and to propose adjustments to the process to recover the residual heavy metals and to upgrade as secondary raw products the co-products generated by the inerting of the slag. © 2006 Elsevier B.V. All rights reserved. Keywords: Secondary lead; Refining; Alkaline slag; Mineralogy; Chemistry; Thermodynamics; Geochemical modelling 1. Introduction Lead consumption in Europe is 2.054 M tonnes/year, more than 70% of which is produced by recycling and, more specif- ically, the recycling of car batteries. Yet the equilibrium of this industry is in jeopardy for two reasons: on the one hand, the source and the cost of the recycled lead mainly supplied by the battery market fluctuates considerably, and on the other hand, the method used so far is recycling by alkaline fusion. Each year the treatment produces 200,000 tonnes of toxic and unstable slag, as well as 280,000 tonnes of sludge from the neutralisation of the sulphuric acid present in the batteries. An evaluation of the pro- cess reveals the negative impact on the environment. With the regulations stiffening in Europe, the possibility of landfilling the waste is diminishing, despite the lack of an economic alter- native to lead batteries. It is therefore important to accurately investigate the nature of the alkaline slag, to evaluate its reac- tivity, and to propose alternative solutions to landfilling, while ensuring the security of the industries that still recycle lead in Europe. The ‘SCORP’ (Pb SCORia) study described in this arti- cle attempts to clarify the approach and the combined tools ∗ Corresponding author. Tel.: +33 2 36 64 34 27; fax: +33 2 36 64 30 62. E-mail address: p.piantone@brgm.fr (P. Piantone). employed (mineralogy, chemistry, leaching, thermodynam- ics), to construct a coherent physicochemical model of slag behaviour. The model was then used to carry out sensitivity analyses with various landfill scenarios, and to propose adjust- ments to the process to recover the residual heavy metals and to upgrade the co-products generated by the inerting of the slag. 2. Material and methods 2.1. Slag production The thermal refining of lead takes place in the liquid phase; the lead must be molten at temperatures bounded by its melting point (327 ◦ C) and its boiling point (650 ◦ C). During molten lead refining, reagents are selectively added to remove other metals (Cu, Sn, As, Ag, etc.) [1]. The battery lead recycling process essentially involves the addition of caustic soda (NaOH) and sodium nitrate (NaNO 3 ) to trap the metals in the form of oxides (arsenites, antimonites and stannites) that are collected on the surface of the molten lead bath. The reduction of the residual sulphates resulting from the battery electrolyte then produces sulphides (NaFeS 2 , FeS, FeS 2 , Na 2 S). Carbon in the form of coke can be added to the molten bath to control the redox couple. The slag produced is cooled in an aerated box allowing complete maturation prior to being sent to a landfill facility. 0304-3894/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2006.02.055