Effects of Slag Composition on H 2 Generation and Magnetic Precipitation from Molten Steelmaking Slag–Steam Reaction

Juncheng Li, Debashish Bhattacharjee, Xiaojun Hu, Dianwei Zhang, Seetharaman Sridhar, Zushu Li

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

In this paper, the effects of slag composition (slag basicity CaO/SiO 2 and FeO concentration) on the amounts of H 2 gas generated and the magnetic spinel phase precipitated as a result of the reaction between synthetic steelmaking slag and steam at 1873 K (1600 °C) were studied by thermodynamic simulation (using Thermodynamic Package FactSage 7.0) and laboratory experiments. The thermodynamic calculation showed that, upon increasing slag basicity (CaO/SiO 2 ) from 1.0 to 2.5, for the reaction of 100 g of slags with 100 g of H 2 O gas, the accumulated amount of the produced H 2 gas increased from 0.17 to 0.27 g, while the amount of magnetic spinel phase first increased and then decreased, with the maximum precipitation of 16.71 g at the basicity of 1.5. When the FeO concentration increased from 15 to 30 pct for the slag with basicity of 2.0, the accumulated amount of the produced H 2 gas increased from 0.17 to 0.28 g, and the amount of magnetic spinel phase increased from 5.88 to 10.59 g. The laboratory experiments were conducted in confocal laser scanning microscope to verify the reaction between 0.2 g of slag and 3.75 L of H 2 O-Ar gas (PH2O=0.2atm). The results indicated that, for 100 g of slags, upon increasing slag basicity (CaO/SiO 2 ) from 1.0 to 2.5, both the produced H 2 gas and magnetic spinel phase first increased and then decreased, with the maximum amounts being 0.09 g of gas and 37.00 g of magnetic spinel phase at the slag basicity of 1.50. For the FeO concentration increasing from 15 to 30 pct, the amounts of both the produced H 2 gas and magnetic spinel phase increased from 0.04 to 0.10 g and from 18.00 to 27.00 g, respectively. The reaction rate between the molten CaO-SiO 2 -FeO-MnO-Al 2 O 3 -MgO slag and the moisture (PH2O=0.2atm) increased with the increasing FeO activity in the slag. The dependence of the reaction rate (mol/cm 2 /s) on FeO content can be expressed as r=(7.67(aFeO)-2.99)×10-7.

Original languageEnglish (US)
Pages (from-to)1023-1034
Number of pages12
JournalMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Volume50
Issue number2
DOIs
StatePublished - Apr 15 2019
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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