Carbothermic reduction of electric arc furnace dust and calcination of waelz oxide by semi-pilot scale rotary furnace

Abstract

The paper gives a common outline about the known recycling techniques from electric arc furnace dusts and describes an investigation of a pyrometallurgical process for the recovery of zinc and iron from electric arc furnace dusts (EAFD). In the waelz process, the reduction of zinc and iron from the waste oxides using solid carbon (lignite coal) was studied. In the reduction experiments; temperature, time and charge type (powder and pellet) were investigated in detail. It was demonstrated that zinc and iron recovery (%) increases with increasing temperature as well as time. Pelletizing was found to be a better method than using the powder as received for the zinc recovery and iron conversion (). In the calcination (roasting) process, crude zinc oxide, which evaporated from non-ferric metals were collected as condensed product (crude waelz oxide), was heated in air atmosphere. Lead, cadmium as well as chlorine and other impurities were successfully removed from crude waelz oxide by this method. In the calcination experiments; temperature and time are investigated in detail. It was demonstrated that zinc purification (%) increases with increasing temperature. The highest zinc refining (%) was obtained at 1200°C for 120 minutes. A kinetic study was also undertaken to determine the activation energy of the process. Activation energies were 242.77 kJ/mol for the zinc recovery with powder forms, 261.99 kJ/mol for the zinc recovery with pellet forms respectively. It was found that, initially, the reaction was chemically controlled

Carbo-Chlorination of Silica: Thermodynamic Simulation and Experimental Study

“…Several routes were used to extract metal from some metallic oxide such as carbo-thermic reduction 26 , electrolysis from molten salt for some active metals 27 and carbo-chlorination. As it was thermodynamically favorable for the formation of chlorides, Ilic et al 28 discussed the chlorination of nickel oxides and nickel ferrites with or without additives and found that the chlorination degree of Ni, Fe, Cr increased with the increase in the quantity of coal.…”

Extraction of zinc from zinc ferrites by alkaline leaching: enhancing recovery by mechanochemical reduction with metallic iron

“…Several pyrometallurgical and hydrometallurgical processes (Jankovi et al, 2014;Langová and Matýsek, 2010;Morcali et al, 2012;Shawabkeh, 2010) have been proposed for the treatment of zinc ferrites. Pyrometallurgical methods are costly owing to high energy consumption and their emissions of toxic gases are considered an environmental problem; hydrometallurgical methods are preferred for process economy and environmental reasons (Copur et al, 2004).…”

Designing of Synergistic Waste Mixtures for Multiphase Reactive Smelting

“…The pyrometallurgical methods for treatment of the EAF dust are preferred, because of the difficulty in leaching of the Franklinite (ZnFe 2 O 4 ) [3][4][5]. Carbon reduces the leaching residue into iron and zinc at high temperatures, so the combination of these two methods can be applied [6]. Mill scale is generated in steelmaking industry; it mainly consists of iron oxides and relatively small amounts of the sulfur, phosphorus, and alkalis [7].…”