Effective treatment and recovery of laurionite-type lead from toxic industrial solid wastes

This study provides a method to recover lead from laurionite-type hazardous industrial solid waste, using mild experimental conditions in terms of temperature and pressure. The waste contained mainly lead, iron and bromide, as Pb(OH)Br and Fe2O3. Almost quantitative recovery of lead and bromide was accomplished, by using 0.1 M HNO3 at room temperature. The resulting acidic leachate (after filtration) was titrated against 1 M NaOH, and the product was found to be mainly Pb(OH)Br. The solid residue from the leaching process was iron oxide (mainly as α-Fe2O3). The respective kinetic experiments indicated that the order of overall dissolution (leaching) reactions were more likely to be a combination between zero- and first-order reactions, although it is difficult to provide any direct physical meaning, due to the possibility of co-existing sequential and parallel reactions, which are directly connected with the extent of examined phases’ crystallization. The obtained results suggest that industrial solid wastes of a similar type can be effectively treated by the application of ambient experimental conditions.