摘要
通过探讨现有水玻璃成分和模数的测试方法,归纳出了影响其测试过程和结果的各种因素;利用酸度计确定了水玻璃中SiO2的滴定终点为pH 5.1,与甲基红-溴甲酚绿混合指示剂的变色点相符,该混合指示剂变色较甲基红敏锐。测试分析证实,NaF作为反应物其加入量对测试结果有显著影响,加入量不足会导致模数测试结果偏低,NaF的加入量一定要过量;在测定SiO2时,以KF代替NaF,溶液澄清,易于观察,有利于滴定终点的判断,KF法简便、快捷,但测试结果较国标法略低。采用甲基红-溴甲酚绿混合指示剂并用KF代替NaF进行滴定分析水玻璃成分和模数是最好的方法。
The determination methods and influence factors of composition and modulus of sodium silicate were provided. It is available to replace the methyl red indicator with Bromocresol green-Methyl red mixed indicator （BGMR）, and the titration process is easier and faster during the determination of the modulus of sodium silicate because the color change of BGMR is more obviously at the titration end point, and the back titration process by sodium hydroxide standard solution can be omitted. It was also discussed by using KF instead of NaF during the titration process to determine SiO2. The result prove that the solution is cleaner than normal and easy to judge the end point, but the modulus is slightly lower. Using BGMR mixed indicator and KF is a good method to realize rapid determination of modulus and composition of sodium silicate.
出处
《铸造技术》
CAS
北大核心
2013年第3期351-354,共4页
Foundry Technology
关键词
水玻璃
模数
甲基红
溴甲酚绿
指示剂
KF
sodium silicate
modulus
methyl red
bromocresol green
indicator
KF
