Approximately 25 Mt/year of sludge and dust are obtained from the treatment of the exhaust gases produced during the manufacturing of cast iron and steel from blast furnace, converter and continuous casting machines. This waste contains a large amount of valuable elements that could be recycled in the steelmaking process itself. Unfortunately, sludge and dust are difficult to recycle and so most of them are disposed in landfills. In this work, a feasibility study on the use of blast furnace sludge as a reducing agent to produce direct reduced iron from BOF-dust is presented. Self-reducing briquettes containing a mixture of BOF-dust, BOF-sludge and BF-sludge were produced. Thermo-gravimetric and roasting tests were performed in non-isotherm conditions from room temperature to 1170 °C in both argon and air atmospheres. The XRD and SEM analysis performed highlighted the metallization ratio of about 50-60% for air reduced briquette and 60-80% for argon reduced briquette. These results foster the technical feasibility of the use of BF sludge as a reducing agent to produce direct reduced iron (DRI). The use of BF-sludge as C-source for BOF dusts reduction lead to a cost saving estimated to 1500 M€/year worldwide.

Experimental analysis on the use of BF-sludge for the reduction of BOF-powders to direct reduced iron (DRI) production

MOMBELLI, DAVIDE;DI CECCA, COSMO;MAPELLI, CARLO;BARELLA, SILVIA;
2016-01-01

Abstract

Approximately 25 Mt/year of sludge and dust are obtained from the treatment of the exhaust gases produced during the manufacturing of cast iron and steel from blast furnace, converter and continuous casting machines. This waste contains a large amount of valuable elements that could be recycled in the steelmaking process itself. Unfortunately, sludge and dust are difficult to recycle and so most of them are disposed in landfills. In this work, a feasibility study on the use of blast furnace sludge as a reducing agent to produce direct reduced iron from BOF-dust is presented. Self-reducing briquettes containing a mixture of BOF-dust, BOF-sludge and BF-sludge were produced. Thermo-gravimetric and roasting tests were performed in non-isotherm conditions from room temperature to 1170 °C in both argon and air atmospheres. The XRD and SEM analysis performed highlighted the metallization ratio of about 50-60% for air reduced briquette and 60-80% for argon reduced briquette. These results foster the technical feasibility of the use of BF sludge as a reducing agent to produce direct reduced iron (DRI). The use of BF-sludge as C-source for BOF dusts reduction lead to a cost saving estimated to 1500 M€/year worldwide.
2016
BF-sludge; BOF-dusts; Direct reduced iron (DRI); Iron sponge; Recycling; Self-reducing briquettes; Chemical Engineering (all); Safety, Risk, Reliability and Quality; Environmental Engineering; Environmental Chemistry
File in questo prodotto:
File Dimensione Formato  
1-s2.0-S0957582016300349-main.pdf

Accesso riservato

: Publisher’s version
Dimensione 2.81 MB
Formato Adobe PDF
2.81 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/997765
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 32
  • ???jsp.display-item.citation.isi??? 25
social impact