Conductometric Determination of Graphite in Propellants by Use of Leco Conductometric Carbon Determinator

摘要

A conductometric method is proposed for the determination of graphite in propellants. The method is applicable to the macro and semi-micro range. A 0.02 to 0.3 gram-sample is dissolved in 10 m1 of nitric acid by heating on the steam bath. If tin is present, 3 drops of hydrofluoric acid are added to prevent the precipitation of metastannic acid and occlusion of organic matter. The solution is filtered through a small Gooch crucible wrapped in aluminum foil to prevent contamination by tarry matter from the adapter. The Gooch is washed with hot dilute nitric acid (1 to 1), water, acetone, and water in that order. It is then heated at 900 - 1000C. in a ceramic tube in a current of oxygen and the carbon dioxide is determined conductometrically using a Leco Conductometric Carbon Determinator. Such factors as the best means for dissolving the sample, possible segregation, preparation of calibration curve, time for combustion, mechanism of the combustion, and interferences are considered. (Author)