CHEMICAL ANALYSIS
The contents of Volatile Matter, Ash, Fixed Carbon and Iron
are obtained according to the following procedures:
(Preparations)
1. Pick up one piece out of the testing lot of Carbon Rods.
2. Remove completely the impregnation ingredient by heating.
3. Pulverrize approxinmately half of the test piece to -200mesh
in a mortar bowl.
4. Dry the pulverized powder in a drying oven at 110 degree C.
5. Prepare an electric furnace (900 degree C. or higher), and
a ceramic crucible of 5cc.
VOLATILE MATTER
---------------
1. Measure weight (W1) of the empty ceramic crucible.
2. Put approximately 1 gram of the dried powder sample in
the crucible, measure its weight (W2), and put a cap on it.
3. Heat it up for 7 minutes in the electric furnace which is
heated up to 850 degree C. beforehand.
4. After heating, immediately more the crucilbe into a desiccator
for cooling.
5. After cooling down to the room temperature, remove the cap, and
soon meausre weight (W3) of the crucible.
6. Calculate the content of Volatile Matter (V%) according to the
following formula:
W3 - W1
V% = ( 1 - ---------- ) x 100
W2 - W1
ASH CONTENT
-----------
1. Scceeding to the Volatile Matter Test, put the crucible in
the furnace again, and continue to heat it for 3 hours at
750 degree C. without the cap.
2. After cooling, meaure weight (W4) of the crucilbe, and calculate
the Ash Content (A%) according to the following formula:
W4 - W1
A% = ( 1 - ---------- ) x 100
W2 - W1
FIXED CARBON
------------
Fixed Carbon (F%) = 100 - (V + A )
IRON CONTENT
------------
1. Take 0.3g of the pulverized sample powder, and mix it with
2.5g of E-Mix. (It is the mixture of Light Magnesia and Absolute
Sodium Carbonate, the mix ratio of which is 2:1 .)
2. Put 0.5g of E-Mix on the bottom of a ceramic crucible.
3. Put the sample powder in the crucible.
4. Heat the crucilbe for 1.5 hours at 800 degree +/- 50 degree C. in
the well ventilated Electric Oven untile the sample mix is completely
ashed.
5. Put the residue in a 200ml beaker, and add 20ml of distilled water.
Dissolve the contamination in the crucilbe with 15ml of Hydrochloric
Acid. transfer the solution to the beaker, and wash the crucilbe
with water.
6. Boil the solution for about 5 minutes to dissolve all solid substances,
and dilute the solution to 100ml. ("A" Solution)
7. Dilute 5ml of "A" Solution with water to 50ml, and take out 10ml
into a beaker.
8. Add to this solution the following:
1ml of Hydrochloric Acid
1ml of Hydroxylamine Hydrochloride Solution (10 W/V%)
5ml of Ammonium Acetate Solution ( 25 W/V%)
2ml of -Phenanthroline Solution (0.1 W/V%)
9. Dilute with water to 25ml. After standing for 20 minutes to
develop color, take the solution into the Photometric Cell of
Atomic Absorption Analyzer.
10. Measure the absorbancy at the wave-length of approximately 400mƒÊ
according to JIS K 00115 general Rules for Atomic Absorption
Analysis.
11. Correct the value by repeating the blank tests, and find the most
appropriate Iron Content value from the Calibration Curve,
preparation of which is as follows:
1) Dissolve 7.02g of Ferrous Ammonium Sulfate ( FeSO4(NH4)2SO4. 6H2O )
in the mixture of 2ml of Hydrochloric Acid and water (1:1) .
2) Transfer to a 1000ml volumetric Flask, and dilute with water
to the mark. Pipette 10ml of this solution into another 1000ml
volumetric Flask, and dilute with water to the mark. Thus,
Iron Standard Solution is obtained. 1ml of this solution contains
0.01mg of Iron.
3) Take several aliquots varying from 0 to 7ml of this Standard Solution.
4) Repeat the procedurers above, and prepare the calibration curve
in relation with Iron Content and Absorbancy.
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