正交试验对熔盐氯化条件的优化

Study on optimal conditions on molten salt chlorination process with orthogonal experiment

为减少干法后处理中氧化物钙热还原环节所产生的放射性废盐数量,需要将废盐中的氧化钙转化成氯化钙以重复利用。以无水氯化氢作氯化剂,采用气体鼓泡法对氯化钙熔盐中的氧化钙进行氯化。通过单因素试验研究熔盐液面高度、反应温度、氯化氢过量值和流量对熔盐氯化率的影响;借助正交试验和极差分析考察影响因素的主次顺序,寻求最优条件组合;利用方差分析检验分析结果的正确性。最终确定熔盐氯化条件的较优组合:熔盐液面高度为75 mm、反应温度为830℃、氯化氢过量60%、氯化氢流量为0.4 L/min,各因素主次顺序为氯化氢过量值、熔盐液面高度、氯化氢流量、反应温度。该工艺可使熔盐的氯化率稳定在95%以上。

To reduce the amount of radioactive spent salt that generated in the direct oxide reduction process in the dry reprocessing of spent nuclear fuel,the calcium oxide that in the spent salt needs to be converted into calcium chloride for recycling.ln this study, anhydrous hydrogen chloride was used as the chlorinating agent, and the calcium oxide in the molten calcium chloride was ehloridized by bubbling method.The influences of factors,such as mohen salt level,reaction temperature, the excessive value and the flow rate of hydrogen chloride, on the chlorination rate were investigated by single factor experiment.The order of the influencing factors was researched by orthogonal experiment and range analysis, and the best combination of condition was obtained.Then the exactness of the results was verified by square variance analysis.At last, the optimal conditions were determined,that were molten salt level was 75 ram,reaction temperature was 830℃, excessive value of hydrogen chloride was 60%, and flow rate of hydrogen chloride was 0.4 L/min.The most important factor was the excessive value of hydrogen chloride, followed by molten salt level, flow rate of hydrogen chloride, and reaction temperature. In this process, the value of chlorination rate can be kept at more than 95%.