用氟硅酸钾容量法测定岩石中的二氧化硅,与重量法相比较有简便、快速等优点,但由于种种原因影响着该法的推广应用,其中最主要的原因是测定结果不够稳定。关于该法测定结果不稳定的原因,许多文献有所介绍,但所得结论不尽相同。例如,有人认为熔样时熔融物向坩埚外“爬”造成的,等等。我们通过实验又找到了一个原因,而且可能是更为重要的原因之一,即发生在洗涤与中和游离酸这一过程。在通常采用的方法中,洗涤液系采用氯化钾的乙醇饱 The determination of silicon dioxide in rock by potassium fluosilicate capacity method is simple and rapid compared with gravimetric method. However, due to various reasons, the main reason for the application of this method is that the determination result is not stable enough. Many of the literature on the causes of instability in the determination of the method, but the conclusions are not the same. For example, it is believed that the melt “creeps” out of the crucible as it melts, and so on. We have found one reason through experiments, and probably one of the more important reasons, that is, the process of washing and neutralizing free acid. In the commonly used method, the washing liquid is saturated with potassium chloride and ethanol