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|  MIL-T-50009A
man. Form a good meniscus on
4.5.2.2.2 Four percent gels. Results of con-
the water collected in the bottom
sistency tests on 4 percent gels within each
set of duplicates shall agree within 50 g.
of the trap by wiping the sur-
face of the trap wall at the inter-
Tests shall be repeated until this condition is
face level, exerting a firm pres-
met, using fresh gel preparation.
sure on the trap wall. Free any
droplets of benzene caught in the
4.5.3 Granulation. Prepare a nest of sieves
water phase with the policeman.
No. 6, 20, and 100 conforming to Specifica-
Remove water adhering to the
tion RR-S-366, and place a receiving pan at
policeman by twirling the police-
the bottom. Place 50.0 g of the specimen on
man in the upper benzene phase.
the No. 6 sieve, cover, and assemble in a
mechanical shaker geared to produce 300
(d) Protect the top of the condenser
15 gyrations and 150 10 taps of the striker
tube by a calcium chloride tube
per minute. Vibrate for 5 minutes with the
or equivalent, except during the
tapper in operation. Weigh portions retained
rinsing and scrubbing operations.
on each sieve and calculate the amounts on a
(e) At all times during the distillation,
percentage basis.
maintain the heating medium at
a level about 1/4 inch below the
4.5.4 Moisture. Weigh out rapidly, to the
level of the suspension in the liter
nearest decigram, approximately 25 g of the
flask.
specimen and immediately disperse in 500
10 ml of benzene in a round bottom liter
(f) Make a blank determination by sub-
flask. After the sample has been dispersed
jecting 500 ml of benzene to the
( approx. 5 min. ) determine the moisture
same treatment as the suspension
content in accordance with method 3001.5 of
and correct all determinations ac-
Fed. Std. 791 with the following exceptions
cordingly.
and additional details:
(g) Determine the efficiency of recovery
(a) Use the entire 500 ml of suspension
by treating similarly 500 ml of
instead of the 100 ml specified.
benzene to which 0.50 ml of water
has been added. If, after correc-
(b) Heat the flask by means of a
tion for the blank, the apparatus
liquid bath or an electric heating
fails to recover 0.50 0.05 ml
mantle. Maintain the temperature
of water, tighten all connections
o f the bath or heating mantle
and repeat the test. No determi-
at 140 5C. during the distil-
nation shall be made with ap-
lation period.
paratus which has not demon-
(c) Distill for 2 hours. Wash down the
strated satisfactory recovery.
condenser tube with three 10-ml
(h) Ground glass connections may be
portions of benzene, scrubbing
used in the apparatus in place of
the tube at the same time with a
the tight-fitting corks, Care shall
stiff brush to loosen water drop-
be exercised to prevent the en-
lets. Resume the distillation for
trance of atmospheric moisture
an additional hour; then re-
by condensation on such joints.
peat the washing and scrubbing.
Remove the condenser and loosen
4.5.5 Chlorides. Weigh 5.00 0.01 g of
the water droplets adhering to
the specimen into a 400-ml beaker. Add 20
t h e side wall of the wrap by
ml of 6 N nitrate acid, and carefully heat
policing clown with a glass rod
until dissolved. Transfer the solution quanti-
equipped with a rubber police-
5
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