Zn还原法制多晶硅副产物ZnCl_2的电解回收

Electrolytic Recovery of ZnCl_2 Byproduct from Zinc Reduction Method for Polysilicon Rroduction

Zn还原法制多晶硅会产生大量的ZnCl2副产物,在不添加其他辅助电解质情况下,成功利用ZnCl2熔盐制备出了Zn,纯度可达70.74%,验收了工艺的可行性。结果表明,在400～550℃范围内,随着电解温度的升高,熔盐电导率逐渐升高,有利于电解反应。但是继续升高温度至700℃时,ZnCl2蒸气压迅速上升到63.204kPa,挥发造成损失十分严重,且易堵塞出气管,反应温度控制在550℃左右较合适。另外,此工艺由于受ZnCl2本身属性的约束,离产业化还有一定距离。

Zinc reduction method for polysilicon production would produce large amounts of ZnCl2. This paper successfully prepared Zinc by ZnCl2 molten salt electrolysis with no other supporting electrolytes, the purity is up to 70.74%. The results show that in the range of 400--550 ℃, the molten salt conductivity gradually increases with the elec- trolysis temperature going up, which is conducive to the electrolysis reaction. But when the temperature goes up to 700 ℃, ZnCl2 vapor pressure rose rapidly to 63. 204 kPa, ZnCl2 losses are very serious by volatilization, and easy to plug the trachea. So the reac- tion temperature is controlled at about 550 ℃ appropriately. In addition, this process due to the constraints of ZnCl2 itself is has a long way to achieve industrialization.