Original Article

Study on preparation of high-strength briquettes and optimization of properties of magnetic powder from steel slag

¹ School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing 10083, PR China
² Iron-making Plant, Baoshan Iron and Steel Co., Ltd., Shanghai 200941, PR China
³ Material Science and Engineering, KTH Royal Institute of Technology, Stockholm, SE-100 44, Sweden

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Received: 10 July 2025
Accepted: 2 February 2026

Abstract

Aiming at the high energy consumption and increased carbon emission problems in the utilization of steel slag magnetic powder sintering, this paper proposes to use cold press molding and then heat treatment process to prepare it into a high-strength agglomerate and put it directly into the blast furnace. Steel slag magnetic powder as the main iron-containing raw materials, with a small amount of iron ore powder to improve the particle size composition, and systematically explore the binder type, moisture addition, molding pressure, particle size composition and heat treatment system on the strength of the agglomerate. The results showed that cement and PSB binder could give better strength of agglomerates at room temperature and high temperature compared with pregelatinized starch, bentonite and water glass; among them, the loss of iron grade of agglomerates prepared by PSB binder was the smallest. The optimized process parameters were: moisture addition of 5%, molding pressure of 87.6 MPa, and heat treatment regime of 600 ° C-40 min. The compressive strength of steel slag magnetic powder agglomerates prepared under these conditions reaches 2295 N at room temperature, 2 m drop strength about 9 times, and high temperature compressive strength about 2200 N at 700 °C, which meets the requirements of blast furnace on the strength of the charge, and provides a feasible way for the high-efficiency and low-carbon utilization of steel slag magnetic powder.