Separation of ZnO from the Stainless Steelmaking Dust and Graphite Mixture by Microwave Irradiation

Abstract

In this study, microwave was used to treat stainless steelmaking dust containing zinc oxide. The effects of heating time, carbon content and zinc oxide content on the removal efficiency of zinc oxide and the reduction efficiency of iron oxide were investigated. Experimental results show that, for the sample with 16% (mass percent, the same below) graphite heated for 10 minutes by 10 kW power microwave, the removal efficiency of zinc oxide is between 80% and 90% and the metallization ratio of iron oxide is between 40% and 60%; Initial zinc oxide content has a slight effect on the removal efficiency of zinc oxide.The results indicate microwave treatment is one of the feasible ways to process metallurgical solid waste containing the metal with low boiling point.

Influence of Different Carbon Content on Reduction of Zinc Oxide via Metal Bath

“…A similar behavior can be observed in the reaction with dissolved carbon listed in (3). A high C content in the iron bath increases the carbon activity and, therefore, the driving force for the reduction of ZnO [6,7,9,10,[17][18][19][20].…”

“…Sci. 2022, 12, 664 2 of 10 Therefore, ZnO*Fe 2 O 3 can be neglected at the trial process temperature described in this paper (1400 • C) [1,2,[6][7][8][9][10][11][12][13][14][15][16].…”

Microwave selective heating of electric arc furnace dust constituents toward sustainable recycling: Contribution of electric and magnetic fields

“…A problem encountered in this approach, is the reaction of Fe3O4 in EAFD with the halogen acids, leading to the formation of iron chloride/bromide, which is carried over to the final leaching solution as Fe 2+ and impairs the extraction of zinc at a high purity [16,17,21]. Since these techniques require significant heat addition, much work has been directed towards studying the use of microwave energy as a heating source for the treatment of EAFD [16,17,[22][23][24][25][26][27]. Ye et al [27,28] reported the possibility of using microwaves for the carbothermic reduction of EAFD with biochar and identified the main heating mechanisms for the system.…”

Microwave-Assisted Reduction of Electric Arc Furnace Dust with Biochar: An Examination of Transition of Heating Mechanism

“…20 Zhou et al and Kim et al also examined the reduction of zinc oxide from dust and found that the dezincification percentage reached 80%−90% rapidly under microwave irradiation. 21 These studies focused on the reduction behaviors of zinc and iron components, with little attention on the other valuable components, like Mn and Cr. Meanwhile, in-depth exploration of the microwave heating mechanism, which controls the reduction performance, 4 has not been carried out.…”

“…To intensify the reduction process, much attention has been devoted to the use of microwave heating for EAF dust treatment in recent years, considering its high thermal efficiency due to volumetric and selective heating features. , It was reported that under microwave irradiation the reduction of metal oxides in the dust could be accomplished in 20 min with a high dezincification percentage (92.79%) using blast furnace slag as the reduction agent . Zhou et al and Kim et al also examined the reduction of zinc oxide from dust and found that the dezincification percentage reached 80%–90% rapidly under microwave irradiation . These studies focused on the reduction behaviors of zinc and iron components, with little attention on the other valuable components, like Mn and Cr.…”