MIL --- DTL --- 150E
4.4 Tests.
4.4.1 Appearance. Visually examine approximately 50 grams (g) of the specimen for form
and color.
4.4.2 Moisture. Heat a moisture dish and its stopper in an oven at 100° to 110°C for 1 hour,
cool in a desiccator, and weigh to the nearest milligram (mg). Transfer approximately 10 g of
the specimen to the dry dish. Stopper and weigh to the nearest mg. Heat unstoppered in an
oven at 100° to 110°C for 1 hour. Cool in a desiccator. Replace the stopper and weigh to the
nearest mg. Repeat the heating for 1/2 hour periods until successive weighings differ by no
more than 1 mg. The total time of heating shall not exceed 5 hours. Calculate the percent mois-
ture as follows:
Percent moisture = 100A
W
where: A = Weight loss in grams after heating, and
W = Weight in grams of specimen.
4.4.3 Assay (as KClO3).
(a) Ferrous ammonium sulfate solution. Dissolve 40 g of ferrous ammonium sulfate
[Fe(NH4)2(SO4)2S6H2O] in a cold 5 + 95 solution by volume of sulfuric acid and dilute to 1 liter
with the sulfuric acid solution. Titrate with 0.1N potassium permanganate solution and calcu-
late the volume in milliliters (mL) of potassium permanganate solution equivalent to 1 mL of
the ferrous ammonium sulfate solution. Determine equivalency under the same conditions of
test as in (b) except that no potassium chlorate will be present.
(b) Procedure. Weigh to the nearest 0.1 mg approximately 0.8 g of the specimen. Dis-
solve in water and dilute to 500 mL in a volumetric flask with water. Transfer a 50 mL aliquot
to a 500 mL Erlenmeyer flask and dilute to 150 mL with water. Add 10 mL of a 1 + 2 solution
by volume of sulfuric acid. Insert a Bunsen valve in the flask and heat the contents almost to
boiling. Add 50 mL of the ferrous ammonium sulfate solution prepared as specified in (a) by
means of a pipet and boil the solution for 2 minutes. Cool the solution, loosen the valve, add
5 mL of concentrated phosphoric acid and 10 mL of a 10 percent solution of manganese sulfate.
Titrate the excess of ferrous ion with 0.1N potassium permanganate solution to a faint pink end
point. Calculate the percent potassium chlorate as follows:
0.2043A(B - C)(100 - D)
Percent potassium chlorate =
W
where: A = Normality of the potassium permanganate solution used,
B = Milliliters of the potassium permanganate solution equivalent to the total
volume of ferrous ammonium sulfate solution added,
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