 |
|||
|
|
|||
| ||||||||||
|
|  MIL-S-13175H(AR)
AMENDMENT 1
Completeness of extraction will be indicated by the absence of
Polystyrene pellets and should be substantiated by constant
values obtained for the weight of the thimble crucible, and
contents as the extraction procedure continues. For this
purpose remove the thimble crucible from the extraction
apparatus and dry it in an oven for 45 minutes at 80 5 C.
% Polystyrene = A-B X 100
w
Where: A =
Weight of sample and crucible before extraction
Weight of sample and crucible after extraction
B=
Weight of sample
W=
2. Sand. Transfer the contents of the thimble crucible to
a 400 ml beaker using approximately 10 ml. of water. Add 35
ml. of concentrated nitric acid. Cover the beaker with a
watch glass, warm on a hot plate until vigorous reaction stops
and then boil down to a volume of approximately 20 ml. Add 10
ml. of concentrated perchloric acid and boil down to a volume
of 3 or 4 ml. After cooling, transfer the residue in the
beaker to a tared 30 ml. medium porosity fritted glass
crucible. Using small portions of water to effect a
quantitative removal, a wash the contents of the crucible with
at least ten 5 ml. portions of water, at room temperature~
using a glass stirring rod to assure good contact with all
portions of the residue. Aspirate between additions of the
wash water and finally aspirate to dryness. Place crucible,
with residue, in a drying oven maintained at 110 5 C. for
a minimum of sixty minutes. Cool the crucible,and residue in
a desiccator and obtain its weight.
% Sand = C-D X
100
w
Weight of residue and crucible
Where: C =
D=
Weight of crucible
w=
Weight of sample, from Section 1.
2
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals