Abstract:

In the process of industrial purification of crude zirconium tetrachloride by using NaCl-KCl molten salt system,in-clusions are enriched in the molten salt system,causing the deterioration of the NaCl-KCl molten salt system.The effect of the main inclusion ZrO₂on the surface tension,viscosity and density of the NaCl-KCl molten salt system was studied by using the rotation method,the pull tube method and Archimedes principle.The results showed that the surface tension of molten salt system with a certain ZrO₂ content decreased with the increase of temperature between 660~740 ℃,and the viscosity was greatly affected by temperature.When the mass content of ZrO₂ was 0%,10%,15% and 20%,the density was independent of temperature,but when the mass content of ZrO₂ was 5%,the density was greatly affected by temperature.When the tempera-ture is constant,the surface tension of molten salt firstly remained stable and then rapidly decreased with the increase of ZrO₂ content;the viscosity gradually increased with the increase of ZrO₂ content;the density increased firstly and then decreased with the increase of ZrO₂ content and then remained stable and unchanged.

Key words: NaCl-KCl molten salt, purification of crude ZrCl₄, surface tension, viscosity, density