Optimization and dust emissions analysis of the air jigging technology applied to the recycling of construction and demolition waste

Abstract

This work aims to evaluate the use of the air jigging technique, a density-based separation technology commonly applied in mineral processing, to upgrade the quality of mixtures (density and geometric properties) that represents the typical composition of construction and demolition waste (CDW) produced in Brazil. In this sense, tests involving the variation of the main operational parameters of jigging (bed expansion rate, pulsation frequency and jigging time) were carried out aiming to find those which provided the best recycled aggregates quality after processing. Also, fines and dust emissions generation during jigging were measured in order to estimate their potential impacts on human health and environment. The results showed that the air jigging process is adequate to improve the quality of CDW by increasing the concrete concentration in the dense product. The use of high bed expansion rates showed to be of major importance to decrease the content of ceramic aggregates in the dense product, allowing obtaining products richer in concrete. Also, the measured properties of the obtained aggregates (size distribution, shape, etc) met the usual standards required for natural aggregates. Finally, material losses and dust emissions generated were negligible in comparison to the total mass processed, although special attention must be given to safety measures due the presence of inhalable particles (<10 µm).