【作者】 杨林；

【导师】 张志业；

【作者基本信息】 四川大学 ， 应用化学， 2004， 硕士

【摘要】 电解法制备磷酸二氢钾具有产品纯度高,对环境污染小,工艺流程短,对设备的腐蚀弱的优点。本文测定了电解法制备磷酸二氢钾的基础数据——电导率,在此基础上,对其工艺流程进行了比较系统的研究。本文测定和研究了三种溶液的电导率。一是研究了磷酸和磷酸二氢钾混合溶液的电导率随温度和摩尔比的变化情况。二是NaOH-NaCl-NaClO3混合溶液的电导率随温度和摩尔比的变化情况。三是研究了氯化钾溶液的电导率随温度和浓度变化的关系。通过对实验数据的线性拟合,得到了三种溶液电导率随温度的变化可以采用公式表达,其相关系数(R2)在0.99以上。前两种混合溶液的电导率随摩尔比变化的趋势可以采用关联式表达,其相关系数(R2)在0.98以上。 通过对实验数据的线性拟合,氯化钾溶液的电导率与其浓度的关系符合关联式,其相关系数(R2)也在0.99以上。本文在测得电导率数据的基础上,研究和讨论了三种工艺路线。以氯化钾、磷酸和氢氧化钠为原料联产磷酸二氢钾和氯酸钠的工艺路线(一)还存在一些问题。利用阳离子交换膜电解氯化钾和磷酸生产磷酸二氢钾并副产氢气和氯气的工艺路线(二)是成功的。经过对实验数据的拟合得到该电解槽的实际分解电压为1.67 V;由实验得出适宜的槽压为3.1～3.2 V;最佳的电解温度为80～90℃;所得到的产品磷酸二氢钾的含量为100.31%,已经达到分析纯磷酸二氢钾的标准。以工业级的氯化钾、湿法磷酸为原料生产磷酸二氢钾的工艺路线(三)是可行的,但是由于所用湿法磷酸没有净化,其中的杂质含量太高,影响了电<WP=3>解的正常进行。另外,本文探讨了湿法磷酸中单一杂质对电解的影响,并得出只要氟硅酸含量低于0.19%、Al2O3含量低于1.47%时,电解就能够顺利进行。三氧化铁的含量对电解的影响较小。本文提出了电解湿法磷酸生产磷酸二氢钾的工艺流程。更多还原

【Abstract】 The purity of monopotassium phosphate prepared by electrolysis is very high, the electrolytic process is short, its pollution to the environment is very light, and its corrosion to the equipment is weak. The electric conductivities that are required by the production of monopotassium phosphate are measured; finally, the processes for preparation of KH2PO4 by electrolysis are studied.Electric conductivities of three kinds of solutions are measured and studied in this paper. Firstly, the relationships between electric conductivities of H3PO4-KH2PO4 solutions and temperature and molar ratio are studied. Secondly, the relationships between electric conductivities of NaOH-NaCl-NaClO3 solutions and temperature and molar ratio are studied. Thirdly, the relationships between electric conductivities of potassium chloride solutions and temperature and molar ratio are studied. Additionally, the equation of is obtained by regressing the experimental data, which can express these relationships between electric conductivities of the three kinds of solutions and temperature, and whose correlative coefficients (R2) are more than 0.99. The equaton of can be obtained by regressing the experimental data, which can express these relationships between electric conductivities of the first two kinds of solutions and molar ratio, and whose correlative coefficients (R2) are more than 0.98. By regressing the experimental data, the relationship between electric conductivities of potassium chloride solutions and concentration () can be expressed by, whose correlative coefficients (R2) are more than 0.99. <WP=5>Three kinds of processes are studied and discussed in this paper. The first process is failed, which is for manufacture of monopotassium phosphate and sodium chlorate from potassium chloride, phosphoric acid and sodium hydroxide. The second electrolytic process is successful, which is for production of monopotassium phosphate, hydrogen and chlorine from potassium chloride and phosphoric acid by using a cationic permselective membrane cell. The actual reduce voltage is 1.6748V, which can be got by the regression of experimental data. The proper electrolytic conditions are obtained, the voltage of electrolytic cell is 3.1～3.2V; The temperature of electrolysis is 80～90℃. The content of monopotassium phosphate is 100.31%. The third process is possible, which uses industrial potassium chloride and wet-process phosphoric acid as material, but in this paper the electrolysis doesn’t work, because the concentration of impurity in wet-process phosphoric acid using is too high. Additionally, the influence of the main impurities in wet-process phosphoric acid on electrolysis was studied in this articale. The conclusion is drawn that if the content of fluosilicic acid in wet-process phosphoric acid is less than 0.19% or the content of dialuminium trioxide in wet-process phosphoric acid is less than 1.47%, the elctrolysis would go on wheels. In addition the influence of diiron trioxide on electrolysis is poor. Finally a process is presented in this paper, which prepares monopotassium phosphate by electrolyzing wet-process phosphoric acid and potassium chloride solutions.更多还原