Manufacturing, curing and mechanical testing of BREX from electric arc furnace dust

Abstract

At present the acute issue is utilization and recycling of metallurgical production wastes; one of which is electric arc steelmaking dust (EAF). In Russia there are up to 30 million tons of dust in the dumps of metallurgical plants and additionally up to 780 thousand tons are added to this amount annually. Considering the amount, the main value is zinc, which content reaches 25 wt%, as well as iron, which content varies from 20 to 50 wt%. The paper presents the results of studies on briquetting of the EAF dust using the technology of stiff extrusion and obtaining brackets. The chemical composition of the initial EAF dust was studied by X-ray spectral analysis using JEOL JSM-7001F electron microscope. The amount of reducing agent was selected based on results of thermodynamic modeling using the TERRA software package. The BREX were produced in a laboratory extruder assembled from an electric motor, a reduction gear, a screw, and a die. Two types of dies were used in the briquetting study. For each type the optimum moisture and binder were selected. The influence of the binder and moisture on the quality of the finished briquettes was evaluated. The BREX drying was studied in order to find out the optimum curing time in the air. In addition, drying at 110 °C was carried out for a comparative assessment of the strength of briquettes depending on the method of drying. The drop tests of the finished briquettes were carried out according to GOST 25471‒82 “Iron ores, sinter and pellets; method for determining dumping strength”. The test results showed the possibility of transportation of the EAF dust briquettes