Recovery of zinc from electric arc furnace dust by vacuum carbothermal reduction

Abstract

Recently, the proportion of electric furnace steelmaking has increased rapidly, and the content of electric arc furnace dust has increased. Through comprehensive recovery of electric arc furnace dust, the harm of metallurgical solid waste can be reduced and economic value can be created. In this paper, it gives a common outline about the known recycling techniques from electric arc furnace dusts and presents the carbothermal reduction under vacuum. The evolution in reduction products in the process of vacuum carbothermal reduction of zinc-containing electric arc furnace dust is studied using the X-ray diffraction (XRD) phase and micro-morphology analysis. The thermodynamic conditions for reduction are computed using Factsage 7.1 program. Through thermodynamic study, it is found that the initial temperature of reducing zinc oxide decreases as the pressure of the system drops. In the process of the vacuum carbothermal reduction experiment, the type of reducing agent, reduction temperature, carbon content, and reaction time are studied. According to the test results, the optimum process parameters are determined as follows: reduction time 30 min, reduction temperature 1273 K. The dezincification effect of electric arc furnace dust can reach over 99%.