In order to cleanly and efficiently extract zirconium from zircon sand (the main component is ZrSiO
4), sodium hydroxide sub-molten salt was used to decompose ZrSiO
4 in this study. When ZrSiO
4 reacts with sodium hydroxide sub-molten salt, the formation of
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In order to cleanly and efficiently extract zirconium from zircon sand (the main component is ZrSiO
4), sodium hydroxide sub-molten salt was used to decompose ZrSiO
4 in this study. When ZrSiO
4 reacts with sodium hydroxide sub-molten salt, the formation of Na
2ZrSiO
5 (a water-insoluble product) considerably affects the separation efficiency of Zr and Si and increases production cost. Thus, it is necessary to control the formation of Na
2ZrSiO
5. The influence of NaOH content, reaction temperature, reaction time, and NaOH/ore mass ratio on the formation of Na
2ZrSiO
5 were systematically investigated. The optimum reaction parameters for the inhibition of Na
2ZrSiO
5 formation were as follows: 80% NaOH content, 245 °C reaction temperature, 4:1 NaOH/ore mass ratio, 10 h reaction time, and 400 r/min agitation speed. These results indicate that ZrSiO
4 is decomposed to Na
2ZrO
3 and Na
2SiO
3 by reacting with NaOH, realizing the separation of Zr and Si, and then the reactions between Na
2ZrO
3 and Na
2SiO
3 result in the formation of Na
2ZrSiO
5, during the decomposition of ZrSiO
4 using NaOH sub-molten salt. The sub-molten salt decomposition process can realize the clean extraction of zirconium, which is conducive to the sustainable development of zirconium resources.
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