Synergetic valorization of basic oxygen furnace slag and stone coal: Metal recovery and preparation of glass-ceramics.

Yong Lin,Timo Fabritius,Baijun Yan,Qifeng Shu

doi:10.1016/j.wasman.2021.08.044

Yong Lin, Timo Fabritius + Show 2 more

Open Access

https://doi.org/10.1016/j.wasman.2021.08.044

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Abstract

A synergetic valorization method was proposed to convert the basic oxygen furnace (BOF) slag and stone coal into ferroalloy and glass-ceramic in this work. Effects of reduction time, temperature, and the mass ratio of BOF slag to stone coal on the reduction were studied. The reduction mechanism was investigated by in-situ observation and dissolution experiments. The effect of sintering temperature on the properties of glass-ceramics prepared from the final slag was further studied. The in-situ observation results indicate that the reduction reactions occurred mainly in the temperature range of 1673-1793K. The reduction ratio of oxides and size of metal droplets can be improved by increasing reduction time, temperature, and decreasing stone coal addition. The recovered ferroalloys consisted of Fe, Mn, P, and V, which has the potential of returning to the steelmaking process or extracting vanadium. The modified final slag was suitable material for preparing glass-ceramic. Wollastonite-based glass-ceramic with a maximum bending strength of 95.83MPa was prepared, which could be applied as abrasion-resistant and building decoration materials. Therefore, the present technological route can convert two kinds of industrial solid waste into two kinds of cleaner products and achieve the target of "zero waste".

Highlights

Basic oxygen furnace (BOF) slag originates from the oxide slagging agent, impurities in pig iron, and erosion of furnace lining
A valorization method of BOF slag by reducing with stone coal was proposed in this work
Ferroalloys were produced by reducing BOF slag with stone coal, and glass-ceramics were prepared by the final slag

Summary

Introduction

Basic oxygen furnace (BOF) slag originates from the oxide slagging agent, impurities in pig iron, and erosion of furnace lining. The BOF slag consists of 40–60 wt% CaO, 10–20 wt% SiO2, 10–30 wt% FexO, 5–15 wt% MgO, 0–5 wt% P2O5, 0–5 wt% MnO and other minor components (Das et al, 2007; Naidu et al, 2020; Fisher and Barron, 2019; Guo et al, 2018a,b). Various application methods have been proposed for the treatment of BOF slag (Das et al, 2007; Naidu et al, 2020; Fisher and Barron, 2019). The utilization of BOF slag is limited by the huge output, fluctuation of composition, high treatment cost, shrinking civil engineering and infrastructure market, and more stringent environ mental regulations, etc. (Naidu et al, 2020; Fisher and Barron, 2019; Guo et al, 2018a,b)

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