Comparison of electric arc furnace dust treatment technologies using exergy efficiency

Multiple methods exist to treat electric arc furnace dust (EAFD), aiming at high metal recovery and low landfilling needs. However, a technology that is energy efficient and recovers both Zn and Fe has only recently been developed to a commercial scale with the Rotary Hearth Furnace. Various other technologies have been proposed as alternatives to the historically preferred Waelz Kiln process. This gate-to-gate study presents an objective method to compare the overall thermodynamic performance and efficiency of treatment technologies through the use of an exergy analysis incorporating the dominant factors without the need of examining every process detail. In addition, the influence of the EAFD zinc content on the exergy efficiency of both the Waelz Kiln and Rotary Hearth Furnace process was studied. The efficiencies of these high temperature metal recovery processes were also compared to the efficiency of the newly proposed In-Process Separation technology.