Basic Study on the Recycling of a Waste MgO-C Refractory Material as a Flux for EAF Steelmaking

Jei-Pil Wang; Hang-Goo Kim; Min-Seok Go; Dong-Hun Lee

doi:10.7844/kirr.2021.30.6.53

All Issue

2021 Vol.30, Issue 6 Preview Page Next Page

Research Paper

Basic Study on the Recycling of a Waste MgO-C Refractory Material as a Flux for EAF Steelmaking 전기로 폐 MgO-C계 내화재의 제강원료 활용 가능성 연구

31 December 2021. pp. 53-60

PDF XML

Abstract

In EAF steelmaking industries, MgO content in slag increases due to the addition of dolomite flux to protect refractory lines of furnaces and improve the desulfurization capability of slag. In addition, coal powder is injected in the molten steel bath to increase the energy efficiency of the process. In this regard, the utilization of waste MgO-C refractory material as a flux was examined because it has high amounts of MgO (>70%) and graphite carbon (>10%). A series of experiments were carried out using industrial EAF slag with added light burnt dolomite and waste MgO refractory material from a Korean steel company. The results for the addition of the two fluxes were similar in terms of slag basicity; therefore, it is expected that waste MgO-C refractory material can successfully replace dolomite flux. In addition, when the waste MgO-C refractory material was added as flux, slag foaming phenomenon was demonstrated because of the reaction between the graphite from the refractory material and iron oxides in the slag.

Keywords

Light burnt dolomite

Steel making

Slag

MgO

Refractory materials

현재 EAF 전기로 제강공정에서는 슬래그 중의 MgO 함량을 증가시켜 탈황능과 내화재 수명을 개선시키고자 돌로마이트(백운석) 용제(Flux)를 첨가하고 있으며, 또한 에너지효율을 증가시키기 위해 용강 중에 가탄재를 취입하고 있다. 이러한 견지에서 폐 MgO-C계 내화재를 재활용하는 연구를 진행하였다. 폐 MgO-C계 내화재는 MgO(>70%)과 탄소(>10%)를 대량 함유하고 있기 때문이다. 이런 목적으로 제강 슬래그를 대상으로 해서 폐 MgO-C계 내화재를 첨가하는 효과를 실험하였고 그 결과를 경소 돌로마이트를 첨가한 결과와 비교하여 폐 MgO-C계 내화재 재활용 효과를 평가하였다. 폐 MgO-C계 내화재를 사용해서 얻은 결과가 슬래그 염기도 측면에서 경소 돌로마이트를 사용한 결과와 유사하게 나타남으로써 기존 경소 돌로마이트 대체 가능성을 확인하였다. 특히 폐 MgO-C계 내화재를 사용한 경우에는, 폐 내화재에 다량 함유된 흑연 성분에 의한 슬래그 중의 철산화물과의 환원반응으로 CO가스가 발생하여 생긴 크고 작은 기포들이 관찰되었으며 이로써 슬래그 Foaming 효과를 기대할 수 있는 것으로 확인하였다.

키워드

경소 돌로마이트

제강

슬래그

MgO

내화재

References

Liesbeth Horckmans, Peter Nielsen, Philippe Dierckx, et al., 2019 : Recycling of refractory bricks used in basic steelmaking : A review, Resources, Conservation & Recycling, 140, pp.297-304. 10.1016/j.resconrec.2018.09.025

Kun Mok Shon, Jang Su Kim, Si Wan Kim, et al., 2002 : Recycling of waste refractory materials for steel, Ceramist, 5(5), pp.35-42.

POSCO Chem-Tech, 2011. KR. KR20110124661A.

Mohammed Tayeb, Andre N. Assis, Seetharaman Sridhar, et al., 2015 : MgO Solubility in Steelmaking Slags, Metallurgical and Materials Transactions B 46(3), pp.1112-1114. 10.1007/s11663-015-0352-8

Ping Wang, Qing-min Meng, Hong-ming Long, et al., 2006 : Influence of Basicity and MgO on Fluidity and Desulfurization Ability of High Aluminum Slag, High Temp. Mater. Proc., 35(7), pp.669-675. 10.1515/htmp-2015-0006

K. S. Kwong., J. P. Bennett., 2000 : Balancing MgO for Foamy Slag and Refractory Protection, D.L. Schroeder & Associates, Twenty Second Annual Symposium, Process Systems for Electric Furnace Steelmaking, Orlando, Florida, 9-10 November 2000.

Deisi Vieiraa, Rodolfo Arnaldo Montecinos de Almeidaa, Wagner Viana Bielefeldta, et al., 2016 : Slag Evaluation to Reduce Energy Consumption and EAF Electrical Instability, Materials Research, 19(5), pp.1127-1131. 10.1590/1980-5373-MR-2015-0720

Young Hwan Kim, Jung-Min Yoo, Hyung-Sic Um, 2019 : Effect of Carbon Materials on the Slag Foaming in EAF Process, Journal of the Korean Institute of Resources Recycling, 28(2), pp.40-45.

A. P. Luz, T. A. Ávila, P. Bonadia, et al., 2011 : Slag Foaming: Fundamentals, Experimental Evaluation and Application in the Steelmaking Industry, Refractories Worldforum, 3(2), pp.91-98.

Kyei-Sing Kwong and James P. Bennett, 2002 : Recycling practices of spent MgO-C refractories, Journal of Minerals & Materials Characterization & Engineering, 1(2), pp.69-78. 10.4236/jmmce.2002.12005

A.N. Conejo, R.G. Lule, F. Lopez, et al., 2006 : Recycling MgO-C refractory in Electric Arc Furnaces, Resources Conservation and Recycling, 49(1), pp.14-31. 10.1016/j.resconrec.2006.03.002

Rodolfo Montecinos Almeida, Deisi Vieira, W. V. Bielefeldt, et al., 2017 : MgO Saturation Analisys of CaO-SiO₂-FeO- MgO-Al₂O₃ Slag System, Materials Research, 21(1).

Marcus Kirschen, 2020 : Visualization of Slag Data for Efficient Monitoring and Improvement of Steelmaking Slag Operation in Electric Arc Furnaces, with a Focus on MgO Saturation, Metals - Open Access Metallurgy Journal, 11(1), pp.17. 10.3390/met11010017

Marcus Kirschen, In-Ho Jung and Gernot Hackl, 2020 : Phase Equilibrium Diagram for Electric Arc Furnace Slag Optimization in High Alloyed Chromium Stainless Steelmaking, Metals, 10(6), pp.826. 10.3390/met10060826

Alena Pribulova, Peter Futas, Jozef Petrík, et al., 2018 : Comparison of cupola furnace and blast furnace slags with respect to possibilities of their utilization, Arch. Metall. Mater., 63(4), pp.1865-1873.

James Bennett, Kyei-Sing Kwong, 2010 : Thermodynamic Studies of MgO Saturated EAF Slag, Ironmaking & Steelmaking, 37(7), pp.529-535. 10.1179/030192310X12706364542669

Fruehan, R J., Li, Y., Brabie, L., 2003 : Dissolution of magnesite and dolomite in simulated EAF slags, ISSTECH- Conference Proceedings, pp.799-812, Iron & Steel Society International Technology Conference and Exposition, Indianapolis, IN., USA, 2003.

Information

Publisher :The Korean Institute of Resources Recycling
Publisher(Ko) :한국자원리싸이클링학회
Journal Title :Resources Recycling
Journal Title(Ko) :자원리싸이클링
Volume : 30
No :6
Pages :53-60
Received Date : 2021-11-26
Revised Date : 2021-12-17
Accepted Date : 2021-12-20
DOI :https://doi.org/10.7844/kirr.2021.30.6.53

Resources Recycling ISSN:2765-3439(Print) 2765-3447(Online) 자원리싸이클링

All Issue