Optimization of the Microwave-Assisted Carbothermical Reduction Process for Metals from Electric Arc Furnace Dust with Biochar

Anton Anzulevich,Dmitrii Pavlov,Alexander Fedii,Dmitrii Kalganov,Leonid Butko,Zhiwei Peng,Valentin Tolkachev,Vasiliy Buchelnikov

doi:10.3390/met11111765

Anton Anzulevich, Dmitrii Pavlov + Show 6 more

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https://doi.org/10.3390/met11111765

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Abstract

The main purpose of this work was to extract valuable metals from EAF dust with the addition of biochar, using microwaves to control and optimize the carbothermical reduction process. To achieve better microwave penetration and the most homogeneous electromagnetic heat source distribution possible in a sample, the content of EAF dust and biochar in centimeter-size spherical particles prepared by the pelletization process was considered to be radially heterogeneous. The content of EAF dust was determined experimentally and the effective permittivity, permeability, and thermal conductivity of the EAF dust as well as biochar–EAF powder mixture were determined using effective medium approximation. The microwave heating of a multilayered pellet of biochar-containing EAF dust was simulated and investigated. The influence of the distribution of the components within the pellet on the effectiveness of the microwave heating was investigated, as was the influence of the biochar conductivity. The interaction of the pellet with both plane waves in free space and with H10 mode waves in a single-mode waveguide was considered. The most optimal distribution of EAF dust and biochar within the pellet for the reduction process was determined.

Highlights

EAF dust is a metallurgical waste produced in the EAF steelmaking process
The relevance of the problem is due to the need to use the accumulated EAF dust and biochar
For the case when the volume fraction of EAF in dust increases linearly from 0 in the core of the pellet to 0.8 in the shell, the fastest heating occurred at a biochar conductivity of 1010.6 s−1 (Figure 8)

Summary

Introduction

EAF dust is a metallurgical waste produced in the EAF steelmaking process. The output of EAF dust is about 1–2% of the EAF charge [1]. Biochar or hydrolysis lignin is a carbon-containing waste produced by the pulp and paper industry [2]. The relevance of the problem is due to the need to use the accumulated EAF dust and biochar. It is important to learn how to use these wastes as a secondary raw material. It is known [3,4] that it is possible to perform the microwave-intensified reduction of Zn, Fe, and Pb from briquettes consisting of carbon and EAF dust under a C/Fe mass ratio of 0.25

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