一种测定镁粉中活性镁含量的新装置及其应用

镁粉在镁工业应用中有着举足轻重的地位,其有效成分为活性镁。国内现行测定活性镁含量的标准方法为气体容量法,该方法对测定环境要求较高,需要反应装置具备极好的气密性,测定流程繁复不易操作。以质量守恒定律为依据,设计了一种用于测定镁粉中活性镁含量的新型化学反应装置,并根据装置结构和工作原理建立了一种新的活性镁测定方法。方法综合考虑了反应过程中生成的水蒸气和挥发的氯化氢气体对测定结果的影响,并通过碱石灰的吸水性和与酸中和反应,有效消除其影响。方法能够测定镁粉中质量分数不小于92%的活性镁。方法应用于镁粉样品中活性镁含量的测定,测定结果的相对标准偏差(RSD,n=12)为0.060%~0.084%。采用实验方法测定2个镁粒中活性镁,测定结果与标示值基本一致,测定差值小于YS/T 617.1—2007标准规定的允许差。

A new device for determination of active magnesium content inmagnesium powder and its application

Magnesium powder plays an important role in the industrial application of magnesium. Its effective constituent is active magnesium. The current standard method for determination of active magnesium content in China is the gas volume method. However, the environmental requirements of measurement in this method are high. The airtightness of reaction device should be excellent. Moreover, the measurement procedures are complicated and hardly operated. A new chemical reaction device for the determination of active magnesium in magnesium powder was designed based on the law of conservation of mass. A new method for the determination of active magnesium was established based on the structure and working principle of this device. The effect of water vapor and volatile hydrogen chloride gas generated in reaction process on the measurement result was comprehensively considered in the method. In addition, the influence was effectively eliminated through the water absorption of alkali lime and the neutralization reaction with acid. The proposed method was applicable for the determination of active magnesium in magnesium powder with mass fraction not less than 92%. The content of active magnesium in magnesium powder sample was determined according to the experimental method. The relative standard deviations (RSD, n=12) of determination results were between 0.060% and 0.084%. The proposed method was applied to determine active magnesium in two magnesium particles, and the found results were basically consistent with the reference values. The measurement error was smaller than the allowable difference specified in the standard of YS/T 617.1-2007.