Thermal and Mass Spectroscopic Analysis of BF and BOF Sludges: Study of Their Behavior under Air and Inert Atmosphere

Mamdouh Omran,Guo Chen,Timo Fabritius,Yaowei Yu

doi:10.3390/met10030397

Mamdouh Omran, Guo Chen + Show 2 more

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https://doi.org/10.3390/met10030397

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Journal: Metals	Publication Date: Mar 19, 2020
Citations: 3	License type: CC BY 4.0

Affiliation: Shanghai University, University of Oulu, Yunnan University

Abstract

Differential thermal analysis (DTA), thermogravimetry (TG), and mass spectrometry (MS) were used to study the thermal behavior of the blast furnace (BF) and basic oxygen furnace (BOF) sludges generated from the iron-making industry. The results indicated that under air atmosphere the two types of sludge are different in their thermal behavior. In BF sludge, the exothermic carbon gasification (CO/CO2) reaction dominated the process, while in BOF sludge, the significant reaction occurred at 755 °C and was associated with a slight mass gain owing to the partial oxidation of Fe3O4 to Fe2O3. Under inert atmosphere, the thermal behavior of both BF and BOF sludges were dominated by a reduction reaction. In BF sludge, the endothermic reactions ranged from 785 to 1115 °C due to the reduction of iron oxides as follows: Fe2O3 → Fe3O4 → FeO → Fe. A total mass loss of about 27.78% was observed in the TG curve. While in BOF sludge, the endothermic peaks corresponded to magnetite reduction to iron (Fe). The overall mass loss of the BOF was approximately 16.92%. The mass spectrum of gases evolution for both BF and BOF sludges revealed that CO/CO2 gases were released from the sludges.

Highlights

Basic oxygen furnace (BOF) and blast furnace (BF) sludges are fine wastes produced from the iron and steel industry [1,2]
Hematite was present in the iron ore pellets which had been fed into the blast furnace
The thermal behavior of BF and BOF sludges were examined by TG/Differential thermal analysis (DTA)/mass spectroscopy (MS)

Summary

Introduction

Basic oxygen furnace (BOF) and blast furnace (BF) sludges are fine wastes produced from the iron and steel industry [1,2]. BF sludge consists of fine-grained materials containing substantial quantities of valuable elements (iron oxides and coke), in addition to minor heavy metals such as zinc, lead, and cadmium [4,5]. The mineralogical composition of BF and BOF sludges consist mostly of iron oxide (hematite, Fe2 O3 , and magnetite, Fe3 O4 ) and coke. The approximate quantity of BF sludge and BOF sludge created at the plant is about 60,000 ton per year/dry basis [7]. Up to 500,000 tons of BF sludge has been generated each year in the European steel industry in the past several decades [5,8]

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