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Preparation of Eutectic KNO3-NaNO3-sorbitol Propellant With Stirring
Summary: my usual method of eutectic KNO3-NaNO3-sorbitol 35-30-35 propellant preparation is described.
KNO3:and NaNO3 reagent grade "pure for analysis". Moisture content 0.1-0.2%. They were milled together with coffee mill, crystals measured 50 microns to 300 microns.
Sorbitol: pharmaceutical grade. Moisture content 0.2-0.3%.
50 g batch of thoroughly mixed powdered KNO3-NaNO3-sorbitol propellant mixture was placed in glass beaker and heated on temperature controlled heat plate with magnetic stirrer. Temperature was measured with thermometer at the bottom of the beaker.
0 min, temperature 22C. The thickness of propellant layer is 5 sm
10 min, 100C, sorbitol starts to melt, occasional stirring with thermometer is started
20 min, 120C, all sorbitol melts
30 min, 160C, magnetic stirring is started
40 min, 180C, complete dissolution of nitrates is achieved (video1, video2)
Propellant is poured into paper dishes.