Recuperación de zinc de polvos de acería por lixiviación selectiva con ácido fosfórico o hidróxido de sodio.

Abstract

Electric Arc Furnace Dust (EAFD) is an environmental hazard due to their high content of metals such as zinc, iron, lead, among others, as well as their small particle size. EAFD can be valorized by different pyro and hydrometallurgical methods. In the present study, we work mainly with steel mill dust containing 26.3% Zn, 20.1% Fe, and 0.9% Pb in the form of magnetite, zincite, and franklinite compounds. The aim is to recover zinc by acid leaching (sulfuric acid and phosphoric acid) and basic leaching (sodium hydroxide), for subsequent recovery of metallic zinc by electrolysis and smelting. The leaching tests are performed in one and two stages, with and without heating at 80 °C. The acid concentrations used are 150 g L-1 and for sodium hydroxide 240 g L-1. The best leaching recoveries were 94% with sulfuric acid, 97% with phosphoric acid, and 80% with sodium hydroxide, using a two-stage process and heating (80 °C). Electrolysis with graphite anode and stainless-steel cathode gives the best recovery results of

zinc deposited on the cathode which can be purified by fusion to 99% purity.