熔盐电解法的气体研究及其对电解的影响

Gas of Molten Salt Electrolysis and Its Impact on Electrodeoxidation

采用离子色谱、火焰吸收等方法分析反应器中的残渣和尾气凝液,结果表明:残渣的主要成分为FeCl_2/FeCl_3、NiCl_2、CrCl_2/CrCl_3和CaCl_2,其中以铁的氯化物含量最高;凝液主要由HCl、HClO、H_2O以及金属氯化物所组成。分析认为反应器内的气体包括:Cl_2、HCl、HClO、H_2O、金属氯化物蒸气和通入的氩气等。模拟计算表明,在常用的1.0L/min的氩气流量下,难以将反应器内的HCl、HClO等腐蚀性气体及时排出反应器,它们与反应器内壁发生反应形成金属氯化物,对设备造成严重腐蚀,并且会对电解过程产生一定的影响。通过模拟计算不同流量的氩气在反应器内的流动状况,并结合尾气吸收实验,确定在2 h的预电解期,氩气通入量宜改为5.0 L/min。在不同的氩气通入方案下电解TiO_2发现,改进后的氩气通入方案有利于电解速度的提高,且设备的腐蚀情况有所缓解。

Ion chromatography and flame atomic absorption were used to analyze condensates collected at various temperatures and slag.The results show that the main components of slag are FeCl2/FeCl3,NiCl2,CrCl2/CrCl3 and CaCl2;the condensates are made up of CaCl2,HCl,HClO,H2O and metal chlorides.The gas in reactor includes Cl2,HCl,HClO,H2O,Ar and metal chlorides.The 1.0 L/min argon flow in reactor at 850°C was simulated,indicating that it is very difficult to vent the HCl,HClO,et al,so these gases react with reactor wall to produce metal chlorides,which leads to serious corrosion.At the same time,HCl and HClO could influence electrodeoxidation.Based on simulation and tail gas absorption experiment,argon flow increases to 5.0 L/min in 2 h of pre-electrolysis,which can effectively vent the HCl,HClO,et al.This improvement could enhance the electrolysis velocity and resolve the corrosion problem.