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MIL-A-3850
tion to boiling, and slowly add 10 ml. of a 10-
reached. Make the electrical connections,
percent solution of barium chloride to the
place the bomb in a bucket of cold water, and
ignite the sample. After 10 minutes remove
boiling solution. Continue boiling for 15 min-
utes, and then allow to stand for 2 hours at
the bomb from the water and release the
a temperature just below the boiling point.
pressure at a uniform rate, so that the oper-
ation requires a t least 1 minute. Open the
Filter the barium sulfate precipiate through
bomb, and examine the contents for traces
a tared filtering crucible and wash thoroughly
of unburned sample. If any traces are found
with hot distilled water. Dry the crucible and
the determination shall be discarded and an-
its contents in an oven, and then ignite at a
other test performed.
temperature of 850 50C. Cool in a desic-
cator and weigh. Calculate the increase in
4.4.2.1.3 Dissolution, precipitation, and cal-
weight of the crucible to percent sulfur con-
culation. --The dissolution and precipitation
tent of the sample, as follows:
of the material shall be carried out as speci-
fied in 4.4.2. The calculation of percent sulfur
content shall be performed as specified in
4.4.2.
where: A = weight of barium sulfate pre-
cipitate, grams.
4.4.9 Ether-extractable matter. --Transfer
W = weight of sample, grams.
an accurately weighed sample of approxi-
mately 4 grams of the lump-free material to
4.4.2.1 Alternative method. --The sulfur
an extraction thimble, and extract with ether
content may also be determined with a Parr-
using a tared extraction flask and a Soxhlet
type oxygen bomb, using oxygen from an
extractor, or equivalent. Use a hot-water bath
external source.
or a steam plate as the source of heat, adjust-
ing the applied heat so that ether drips from
4.4.2.1.1 Apparatus.
the reflux condenser at the rate of 2 to 3 drops
4.4.2.1.1.1 Bomb. -- Self-sealing oxygen
per second. Continue the extraction for at
combustion bomb equipped with a double
least 8 hours. Remove the extraction flask
valve (see 6.3),
and evaporate the ether by heating on a steam
bath until approximately 26 ml, of the ether
4.4.2.1.1.2 Cup. --Stainless steel cup of a
solution remains. Complete the evaporation
capacity of 6.5 ml.
to dryness by blowing a slow current of dry
air over the solution, Dry the flask to constant
4.4.2.1.1.3 Firing wire. --Iron-nickel-chro-
weight in a vacuum desiccator containing sul-
mium alloy wire of 0.0063-inch nominal di-
furic acid, Calculate the gain in weight of the
ameter.
flask to percent ether-extractable matter.
4.4.2.1.2 Ignition --The firing wire shall
4.4.4 Volatile matter.
be clean and so arranged that it will touch
4.4.4.1 Apparatus.
the sample when the cup is placed in position
in the bomb. Place 5 ml. of distilled water in
4.4.4.1.1 Crucible. -- A platinum crucible
the bomb to saturate the oxygen used for
with a capacity of approximately 20 ml. (ap-
combustion with water" vapor. Place an ac-
proximately 25 mm. in diameter and 35 mm.
curately weighed portion of approximately
deep), and equipped with a closely fitting
0.4 gm. of the sample in the cup. Place the
platinum cover.
cup in the bomb, and close the bomb. Tighten
4.4.4.1.2 Burner. --A Mekker-type burner
the bomb cover firmly to avoid blowing the
having a top approximately 42mm. in diame-
sample from the cup, and allow the oxygen
ter, and giving a flame approximately 16 cm.
to flow into the bomb. Cease the addition of
high (see 6.4). The temperature of the flame
oxygen after a pressure of 40 atmospheres is
3

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