Sequential Extraction for Evaluating the Behaviour of Selected Chemical Elements in Light weight Aggregates Manufactured From Mining and Industrial Wastes

The chemical extraction of twenty-nine elements in a washing aggregate sludge, a clay-rich sediment, a sewage sludge, the mixtures of these materials and the artificial lightweight aggregates (LWAs) manufactured with them was determined by applying the optimized European Community Bureau of Reference sequential extraction procedure in order to establish the effect of the thermal treatment on the extraction of the selected elements. In accordance with the UNE-EN-1744-3 standard (2003), which states a single extraction procedure, preparation of eluates by aggregate leaching was also carried out. All the elements are mainly associated with the residual fraction in the LWAs so their availability is relatively low. The element that presented the highest concentration in the eluates after completion of the single extraction procedure was Fe. All the studied elements are in concentrations below the limit values for inert wastes so, from the standpoint of chemical leaching, the studied LWAs may be used in lightweight concrete manufacturing.