THERMODYNAMIC ANALYSIS OF ZINC STATUS IN THE UPSTREAM EAF OFFGAS CLEANING SYSTEMS ASSOCIATED WITH IN-PROCESS SEPARATION OF ZINC FROM EAF DUST Naiyang Ma 1 1 ArcelorMittal Global R&D - East Chicago Laboratories; 3001 E Columbus Dr.; East Chicago, IN 46312, USA Keywords: Electric arc furnace dust; Zinc; Recycling; In-process separation; Thermodynamics Abstract Electric arc furnace dust is a listed hazardous solid waste and is thus subjected to a high treatment cost. Development of cost-effective technologies to recycle the dust is always a challenge. There are two critical problems in existing recycling practices of electric arc furnace dust: (1) iron in the dust is not recovered and is lost in slags or residues; (2) recovery of zinc from zinc-lean electric arc furnace dust is more costly. Strategy of in-process separation of zinc from electric arc furnace dust, being aimed at producing two recyclable electric arc furnace offgas byproduct streams, zinc- rich one and iron-rich one, has been recently proposed to attack these two problems. However, suitability of facilitating this strategy in electric arc furnace offgas cleaning systems has been questioned. In this study, thermodynamic analysis on zinc status in the upstream electric arc furnace offgas cleaning systems was carried out to examine possibilities of applying in-process separation strategy in producing cleaner byproducts of both zinc-rich dust and iron-rich dust for complete recycling of the electric arc furnace dust. Introduction Due to high flexibility, strong capability of recycling scrap, low energy consumption and low CO2 emissions, electric arc furnace (EAF) steelmaking has grown greatly in the worldwide range. At present, about 63% steel in the United States, 50% steel in Europe and 29% steel worldwide are produced by electric arc furnaces .[1-3] However, along with steel production, electric arc furnaces also generate EAF dust. EAF dust generation rate varies from furnace to furnace, depending on raw materials, steel grades and operating conditions. On average, EAF dust generation rate is about 15 kg per ton steel. [4-6] In 2014, steel production was 88.3 million tons in the United States and 1,661.5 million tons globally. [7] Therefore, it can be estimated that in 2014, EAF dust generation was about 834,000 tons in the United States and 7.23 million tons worldwide, respectively. EAF dust is a listed hazardous solid waste in most of the countries on this planet. There are generally two methods which are allowed for treating the hazardous EAF dust. One is to chemically stabilize the EAF dust first and then dispose the treated dust at well-lined landfills. The other is to send the EAF dust to zinc recyclers if the EAF dust contains sufficiently high level of zinc. However, there are a series of critical issues with current EAF dust treatment. First, treating EAF dust with both landfilling and recycling is rather expensive and has imposed a heavy financial burden on EAF steelmaking companies. Technologies are badly needed for relieving EAF 29 REWAS 2016: Towards Materials Resource Sustainability Edited by: Randolph E. Kirchain, Bart Blanpain, Christina Meskers, Elsa Olivetti, Diran Apelian, John Howarter, Anne Kvithyld, Brajendra Mishra, Neale R. Neelameggham, and Jeff Spangenberger TMS (The Minerals, Metals & Materials Society), 2016