A study of the viscous properties with NaF additions in the CaO-SiO 2-12 mass pct Na 2O based slags

Gi Hyun Kim, Il Sohn

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Abstract

The viscous behavior of the CaO-SiO 2-12 mass pct Na 2O based slag system with various concentrations of NaF has been studied using the rotating spindle method. NaF additions decreased the viscosity by interacting with bridged oxygens in the complex silicates and depolymerizing the network structure of the molten slag. NaF was particularly effective at lowering the viscosity in small amounts, but beyond 8 mass pct NaF, the effect was not as pronounced. A comparison between additions of NaF and CaF 2 revealed NaF to be more effective at decreasing the viscosity for 1523 K and 1573 K (1250 °C and 1300 °C). From the slopes of the Arrhenius relationship for viscosity, the activation energy of viscous flow was found to be between 128 kJ/mol to 115 kJ/mol, which were lower than the values for the same amount of CaF 2 additions. Both a temperature effect and a compositional effect on the molten slag structure and subsequently the viscous behavior were observed. The Fourier transformed infrared (FTIR) spectra taken for the CaO-SiO 2-12 mass pct Na 2O-8 mass pct NaF slag samples quenched from 1623 K to 1773 K (1350 °C to 1500 °C) revealed that the temperature effect on the viscosity was observed at temperatures below 1673 K (1400 °C).

Original languageEnglish
Pages (from-to)1218-1223
Number of pages6
JournalMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Volume42
Issue number6
DOIs
Publication statusPublished - 2011 Dec 1

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All Science Journal Classification (ASJC) codes

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

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