Explorando los sedimentos contaminados como una fuente potencial de recursosun enfoque de procesamiento de minerales para la recuperación de materiales críticos

Abstract

Several metal(loid)s, such as arsenic, cadmium, copper, lead, and zinc, can be found in low concentrations in marine sediments and pose an environmental threat. However, these elements have economic value, leading to the use of physico-chemical separation processes for recovery. To date, magnetic separation has not been used effectively for this purpose. This study aimed to apply wet high-intensity magnetic separation (WHIMS) to extract these elements from contaminated sediments collected in the Avilés estuary in North Spain. A 50 kg composite sample was analyzed through wet-sieving and ICP-MS, revealing that the majority of the material (62%) was in the 125-500 µm grain size fraction, which revealed lower concentrations of these elements compared to the <125 µm fraction, the most contaminated one. Then, WHIMS was applied to both grain size fractions at different voltage intensities, resulting in excellent recovery rates, especially for the coarser fraction. Microscopy analysis indicated that magnetic separation concentrated metal-enriched particles with high iron content into a smaller volumen of sediment. These results suggest that magnetic separation is a feasible option for the recovery of metal(loid)s from contaminated sediments, offering a dual benefit of restoring the coastal area and retrieving valuable materials.