电化学方法检测连铸保护渣中氟含量

发布时间：2018-04-25 00:22

  本文选题：氟 + 测定　； 参考：《华北理工大学》2017年硕士论文

【摘要】：氟化钙在连铸保护渣中起着助熔剂的作用,可以降低连铸保护渣的熔点,有利于保护渣的熔化,并降低保护渣的粘度,从而改善液渣的流动性。但在连铸过程中保护渣氟化钙中氟的逸出并进入大气,会对环境造成严重的污染。研究中采用电化学方法进行连铸保护渣中氟含量进行测定。探讨了测定溶液的条件和保护渣样品的分解条件对氟测定的影响。以甘汞电极为参比电极,用氟离子选择电极对电极电势进行氟的测定,氟离子测定时采用的总离子浓度缓冲溶液(TISAB)是:环己二胺四乙酸二钠盐(CDTA)-磷酸氢二钾-磷酸二氢钾(p H5.8),温度为30℃,氟离子浓度在2×10~(-4)~4×10~(-3)mol/L范围内,E和lgc F-呈现良好的线性相关性,线性方程为y=-62.493x-51.89,相关系数为R2=0.9978;实验了连铸保护渣样品分解的不同熔剂效果,确定了在0.1g保护渣样品下,最佳熔剂及用量为:1.2g Na_2O_2+0.6g Zn O,最佳的熔样温度范围为750℃~800℃;通过实验确定了采用热水进行熔渣浸取效果较好;通过标准加入法测定了在保护渣样品中加入氟化钠后氟的回收率,当氟化钠加入量在2%~8%范围内时,氟的回收率在98.9%~103.3%范围内,结果满意。在上述最佳条件下,对4个氟含量在2.27%~7.23%的不同的保护渣样品进行了测定,平行样测定值相符性较好,说明了该测定方法的可行性。
[Abstract]:Calcium fluoride acts as a flux in continuous casting mold flux, which can reduce the melting point of continuous casting mold powder, be beneficial to the melting of mold powder, and reduce the viscosity of mold slag, thus improving the fluidity of liquid slag. However, in the continuous casting process, the release of fluorine from the mold powder calcium fluoride and its entry into the atmosphere will cause serious pollution to the environment. The fluorine content in continuous casting mold powder was determined by electrochemical method. The influence of the conditions for the determination of fluorine and the decomposition condition of the mold powder sample on the determination of fluorine was discussed. The fluorine potential of the electrode was determined by fluorine ion selective electrode with calomel electrode as reference electrode. The total ion concentration buffer solution (TISAB) used in the determination of fluorine ion is: cyclohexanediamine tetraacetic acid disodium salt, CDTA-dipotassium phosphate, potassium dihydrogen phosphate, potassium dihydrogen phosphate, pH 5.8, the temperature is 30 鈩，

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