The applicability of soil flushing technology in a metallurgical plant

Abstract

Soil flushing technology is an 'in situ' remediation technique involving the injection of a liquid solution. Applications of the soil flushing technique depend on the leachability of the pollutants and the environmental compatibility and total volumes of the solutions used. Therefore, experiments should consider these aspects by simulating the real phenomenon and using the most suitable reagents for the leachability of the different mineralogical forms present. Thirtyone laboratory tests were carried out (in batch and becker) to the complete exhaustion of the leaching capacity according to pH measurements. The reaction kinetics were studied by producing more than 300 solution samples during which the principal heavy metal concentrations, pH and Eh were measured. Leaching solutions containing various concentrations of hydrochloric, sulphuric, nitric and acetic acids were used. Mercury was leached using potassium iodide and acetic acid (pH 2). Analytes such as arsenic, cadmium, mercury, lead, selenium and zinc proved to be leachable in the investigated soil layer. However, high removal efficiencies could be obtained using different typological solutions, concentrations and volumes. The paper discusses the applicability of the soil flushing technique for different heavy metal contents and pH conditions of the flushing solution.

Characterization of Pb-Bearing Minerals in Polluted Soils from Closed Mine Sites

“…Containment can involve surface capping, encapsulation, or transfer to landfill and is used for soil removed from a contaminated site. Removal can involve soil washing (Isoyama and Wada 2007;Yoo et al 2017), soil flushing (Manca et al 2018), electrokinetic (EK) extraction (Acar et al 1995), and phytoremediation (Alaboudi et al 2018), but only soil washing has been used in practice, with the other techniques still being developed or having been used only at pilot scales. Solidification and stabilization can involve vitrification and chemical stabilization, but there are limited uses for treated soil (US EPA 1991).…”