废水中氰化物加压水解反应动力学及工艺条件的优化

Kinetics of pressured hydrolysis reaction of cyanides in wastewater and the optimization of reaction conditions

研究了含氰废水的加压水解反应动力学及反应条件。结果表明,KCN的加压水解反应对CN-符合一级反应动力学规律;在不同pH和水解温度下,KCN溶液中CN-加压水解反应速率常数不同;该水解反应平均活化能为33.2kJ/mol。实验证明,升高温度、增加溶液pH均可提高CN-的去除率;当pH>12时,CN-的去除率随pH变化趋缓。通过正交试验得出含氰废水加压水解的最佳处理条件为处理时间80min、温度180℃、pH为11.0,该条件下,对CN-质量浓度达300mg/L的含氰废水进行处理,CN-的去除率达91%以上。

Kinetics and reaction conditions of pressured hydrolysis of cyanides in wastewater is studied. The result shows that pressured hydrolysis of CN- in potassium cyanide (KCN) solution follows the firstorder reaction kinetics. The constants of reaction rate of CN- in potassium cyanide (KCN) solution are different under different pH and pressured hydrolysis temperature;The average activation energy of pressured hydrolysis is 33.2 kJ/mol. It is proved that with the increasing of temperature and pH,the removal rate of CN- gets higher, but it gets lower when pH is above 12.The orthodoxy trials show that the best reaction conditions of pressured hydrolysis of cyanide are as follows: treatment time is 80 min; temperature is 180 ℃;pH is 11.0. Under these conditions, the removal rate of CN- reaches more than 91% in cyanidecontaining wastewater with 300 mg/L of CN-.