Thermodynamic analysis of zinc status in the upstream eaf offgas cleaning systems associated with in-process separation of zinc from EAF dust

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, zincrich 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.