Abstract: In order to obtain the good liquidity of slag and optimize the slagmetal separation in ferrochrome process, the investigation of the effect of Al₂O₃ and MgO on the viscosity of Cr-containing slag has great theoretical value. From the viewpoint of microscopic structure, the effect of Al₂O₃ and MgO on the viscosity has been investigated by Raman spectroscopy. Experimental results indicate that the viscosity of Cr-containing slag increases with the increasing Cr₂O₃ and Al₂O₃ content，whereas decreases with increasing MgO at the Newtonian flow region. Combined with Raman spectrum analysis results, the amounts of more polymerised units Q²_Si and Q³_Si  increase with the increasing of Al₂O₃  content, and the less polymerised units Q¹_Si and Q⁰_Si decreases, the number of nonbridging oxygens per Si atom (NBO/Si) participating in the formation of network structure decreases, while the degree of polymerization is greater. Along with the increase of the content of MgO, the more polymerised units Q³_Si transform into the less polymerised Q¹_Si and Q⁰_Si, the NBO/Si ratio increases, and the degree of polymerization gets lower, variation tendency of slag viscosity is consistent with polymerization degree, therefore, through the analysis of contents on the degree of polymerization can directly reflect the variation of viscosity.

Key words:  , Cr-containing slag；viscosity；structure；Raman spectroscopy