Recuperación de zinc proveniente de polvos de acería usando solventes eutécticos profundos (DES) : Recuperación de zinc proveniente de polvos de acería usando como agente lixiviante el DES relina (Urea + Cloruro de colina).

Abstract

Steel mill dusts are hazardous residues generated in steel fusion and refining operations. These residues contain heavy metals such as zinc, lead, and cadmium, with zinc being the predominant component due to its corrosion-resistant properties. Although current methods exist for treating these residues, such as physicochemical, pyrometallurgical, or hydrometallurgical processes, most of them pose environmental challenges and are costly. With the aim of identifying a more sustainable approach, this study focused on zinc recovery from steel mill dusts using a deep eutectic solvent (DES) known as reline. Unlike conventional acids, reline is non-corrosive and non-toxic. Experiments were conducted at different temperatures (30° C, 60° C, and 90° C) and using various oxidizing agents (iodine, potassium permanganate, and air). Subsequently, zinc recovery of the leaching was achieved through electrodeposition under optimized operational conditions. The highest recovery achieved was 48.84 % at a temperature of 60°C using iodine as the oxidizing agent. Furthermore, it was observed that leaching efficiency depends on both the type of DES employed and the chemical and mineralogical composition of the steel mill dusts. Therefore, understanding the interaction between the involved compounds is pivotal before conducting any experiments. During electrodeposition, 3.66 mg of zinc were deposited in the cathode, with a total recovery of 0.19% due to the slow kinetics in DES systems. In summary, this study explored an environmentally friendly approach to treat steel mill dust and achieve efficient zinc recovery.