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Research SummaryPyrometallurgical Processing How would you… …describe the overall significance of this paper? This paper describes a new technology to process electric arc furnace (EAF) dust. Instead of conventional heating, microwave heating is utilized, which gives different heat transfer and mass transfer mechanisms. …describe this work to a materials science and engineering professional with no experience in your technical specialty? Microwaves can heat zinc ferrite in the EAF dust quickly and efficiently. This is advantageous for the reduction of zinc ferrite to iron and zinc metals in a mixture with carbon. The reducing atmosphere environment prevents the reoxidation of zinc. Conventional heating processes yield zinc oxide instead of zinc metal. …describe this work to a layperson? Electric arc furnace dust is a hazardous material collected from the emissions of steel mills and contains iron, zinc, and other metals. Recycling of the material is difficult and expensive. This microwave technology offers a new heating method, which has high efficiency for the EAF dust recycling.An ideal treatment for electric arc furnace (EAF) dust is to cost-effectively process the dust on site to generate high-value products. Microwave heating has the potential to be the ideal approach. In this study, testing was conducted to evaluate the feasibility of treating EAF dust under microwave radiation to produce iron metal and zinc metal instead of zinc oxides as coproducts. Microwave processing time and fixed carbon addition amounts were investigated. Different carbons with high fixed carbon contents were also tested and no significant influence was observed. Products of both metallic zinc-rich particles and metallic iron-rich residuals exhibited high purities, which satisfy recycling feedstock requirements.

In searching for a low cost adsorbent for mercury removal from flue gas, this study focuses on the utilization of unburned carbons from fly ash as the substitute material for the costly activated carbons. In this first paper of the series, various separation technologies are introduced for the extraction of unburned carbon from different sources of fly ash. The unburned carbons have been efficiently separated from clean ash, which is a value-added product for the concrete industry, with the separation technologies such as gravity separation, electrostatic separation, and froth flotation. Carbon concentrate with a LOI (Loss On Ignition) value of 67~80% has been generated from the processes. Characterization of the carbon products has been performed to determine the physical and chemical properties of the material. It has been found that the unburned carbon particles had a porous structure, which is similar to the activated carbon. The BET surface area of these materials was in a range of 25~58m 2 /g. The majority of the pores are in the range of macropore, and some parts of the surface were embedded with glass spheres. There is a linear relationship between the LOI value and the carbon and sulfur content in the carbon concentrate. Chemical analysis indicated that the mercury content in unburned carbon was much higher than the other separation products, which suggests that the carbon has certain ability to capture mercury from flue gas.

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The effects of catalyst and external electric field on hydrogen storage were evaluated for mesoporous nickel oxide and magnesium oxide. When Pt was introduced into the metal oxides, the capacity of hydrogen adsorption increased remarkably. Furthermore, the measurements of hydrogen adsorption were also carried out on metal oxides by using piezoelectric materials PMN-PT to generate the external electric field. It was observed that the external electric field can increase hydrogen uptake by 37.5% for nickel oxide and 25% for magnesium oxide in a pressure range from 0 to 60 bar. Our DFT calculations support this electrical field enhancement.