Chemical partitioning in lightweight aggregates manufactured from washing aggregate sludge, fly ash and used motor oil.

The optimized BCR sequential extraction procedure was applied to washing aggregate sludge and fly ash, the raw materials used to produce artificial lightweight aggregates (LWAs) in a previous study. The mixtures of the raw materials and the two types of LWAs obtained have also undergone this procedure. As a result, it has been possible to evaluate the effects of the heating process on the extraction behaviour of twenty-eight elements. The thermal process reduces the availability of all the studied heavy metals, with the exception of Mo. The availability of the other elements is also reduced, with the exceptions of As and Sb, which increase in the non-residual fractions.