Phases Reconstruction and Foaming Modification of Basic Oxygen Furnace Slag on Its Grindability

Ruiheng Xiang,Dandan Wan,Jiazhan Wei,Rongjin Liu,Jintao Fan,Cheng Hu,Ping Chen

doi:10.3390/cryst11091051

Abstract

Basic oxygen furnace (BOF) slag is a main byproduct produced during the converter steelmaking process. The poor grindability of BOF slag limits its added-value application. In this paper, the grinding characteristics of unmodified and reconstructed BOF slag were compared. Additionally, the grinding property of reconstructed steel slag was also studied after SiC foaming. The results show that the solid solution of divalent metal oxides’ RO phase, considered as the hardly grinding phase, discomposes after lime-bauxite reconstruction. The characteristics of BOF slag were tested through particle size analysis, XRD, SEM and MIP. The SSA (specific suface area) and the particle diameter of unmodified BOF slag could reach 303.1 m2/kg and 51.75 µm after 10 min of grinding, but that of reconstructed BOF slag could reach 354.5 m2/kg and 18.16 µm after the same grinding time, respectively. The grinding efficiency of steel slag was obviously increased and the particle characteristics were improved after foaming modification. BOF formed as a porous structure after SiC foaming; its porosity, SSA, and particle diameter can reach 31.79%, 424.4 m2/kg, and 24.36 μm and increased by 10.31%, 19.72%, and 39.04%, compared with the reconstructed steel slag of undoped foaming agent, respectively, and the grindability was further improved. A theoretical basis for large-scale BOF slag utilization is provided.

Highlights

College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China; GuangXi Key Laboratory of New Energy and Building Energy Saving, Guilin University of Technology, Guangxi Engineering and Technology Center for Utilization of Industrial Waste Residue in Building
It is estimated that Portland cement production accounts for nearly 7% of the total global CO2 emissions annually [2,3]
Lime and bauxite were selected as tempering components to reconstruct the Basic oxygen furnace (BOF) slag at a high temperature of 1290 ◦ C according to previous study [20], in order to increase the content of C2 S and C4 AF as the main mineral components of BOF slag and reduce the content of the RO phase

Summary

Introduction

College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China; GuangXi Key Laboratory of New Energy and Building Energy Saving, Guilin University of Technology, Guangxi Engineering and Technology Center for Utilization of Industrial Waste Residue in Building. The grinding characteristics of unmodified and reconstructed BOF slag were compared. The grinding property of reconstructed steel slag was studied after SiC foaming. The grinding efficiency of steel slag was obviously increased and the particle characteristics were improved after foaming modification. SiC foaming; its porosity, SSA, and particle diameter can reach 31.79%, 424.4 m2 /kg, and 24.36 μm and increased by 10.31%, 19.72%, and 39.04%, compared with the reconstructed steel slag of undoped foaming agent, respectively, and the grindability was further improved. CO2 gas emissions from cement and concrete production are becoming a global concern, and many researchers are working on the development of silicate cement substitutes to produce less environmentally damaging cementitious materials. In recent years, increasing attention has been paid to the use of waste and by-products from industrial production as a partial solution to environmental and ecological problems

Methods

Results

Conclusion