A Study on the Separation and Iron Recovery from Steelmaking Slag Using Continuous Multi-Stage Magnetic Separation

Seolji Nam; Sungkoo Jo; Hoonha Lee

doi:10.7844/kirr.2025.34.5.53

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2025 Vol.34, Issue 5 Preview Page Next Page

Research Paper

A Study on the Separation and Iron Recovery from Steelmaking Slag Using Continuous Multi-Stage Magnetic Separation 연속식 다단 자력선별을 이용한 제강슬래그 선별 및 철원 회수에 관한 연구

31 October 2025. pp. 53-59

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Abstract

In this study, we developed a continuous multi-stage magnetic separation process to reduce greenhouse gas emissions in steelmaking by using weak magnets to enhance the resource recovery of slag from a basic oxygen furnace (BOF) for use as a raw material in cement production. This process overcomes the limitations of conventional batch-type magnetic separation with strong magnets by classifying the slag into five fractions (M1–M4 and NM) according to their magnetic properties. The results of an experimental evaluation of the proposed method show that the M1 fraction, containing 89.0 wt% Fe, can serve as a substitute for scrap iron, whereas the M2 fraction, with 46.8 wt% Fe, has potential as a sintering feed. Of note, the NM fraction exhibited a high CaO content of 35.4 wt% and can be used as a substitute for limestone in cement manufacturing. Quantitative and qualitative analyses using 3D X-ray computed tomography confirmed changes in the distribution of Fe before and after magnetic separation, which demonstrates that Fe was recovered efficiently and that the utilization of nonmetallic components added value. These findings indicate that the proposed process is technically feasible as an environmentally beneficial strategy for advanced resource recovery of steelmaking by-products.

Keywords

Steelmaking slag

Magnetic separation

Continuous multi-stage process

Resource recovery

본 연구는 철강 산업에서 발생하는 부산물인 전로슬래그를 효과적으로 자원화하고, 이를 시멘트 산업의 원료로 활용하여 온실가스 배출 저감에 기여하기 위한 방안으로 약자석을 이용한 연속식 다단 자력선별 공정을 개발하였다. 기존의 강자석을 이용한 배치식 자력선별 방식의 한계를 개선하기 위해 약자석을 활용하여 슬래그를 M1~M4, NM으로 분류하였다. 실험 결과, M1 시료는 89.0 wt%의 Fe를 포함하여 철스크랩 대체 자원으로 활용 가능하며, M2 시료는 46.8 wt%의 Fe를 함유해 소결 원료로서의 활용 가능성을 확인하였다. 또한 CaO 함량이 35.4 wt%로 높은 NM 시료는 석회석 대체 원료로 시멘트 제조 공정에 활용될 수 있는 가능성을 보였다. 3D X-CT 분석을 통해 자력선별 전후 슬래그 내 Fe 분포의 변화를 정량적, 정성적으로 검증하였으며, 이를 통해 슬래그 내 함유된 철원의 활용과 비금속 자원의 고부가가치화를 동시에 달성할 수 있음을 확인하였다. 따라서 제안된 연속식 다단 자력선별 공정은 제철 부산물의 고도화된 자원화 기술로서 기술, 환경적 측면에서 유의미한 적용 가능성을 제시한다.

키워드

제강슬래그

자력선별

연속식다단공정

자원회수

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Information

Publisher :The Korean Institute of Resources Recycling
Publisher(Ko) :한국자원리싸이클링학회
Journal Title :Resources Recycling
Journal Title(Ko) :자원리싸이클링
Volume : 34
No :5
Pages :53-59
Received Date : 2025-07-24
Revised Date : 2025-08-28; 2025-09-25
Accepted Date : 2025-10-02
DOI :https://doi.org/10.7844/kirr.2025.34.5.53

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

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