GB/T 3813-1983 Method for determination of density of montan wax GB/T3813-1983 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of density of montan wax
Determination of density of montan wax The standard is applicable to the determination of the density of montan wax. UDC 665.44
GB 3813—83
Method points: The ratio of the weight of the wax sample at 20℃ to the weight of water of the same temperature and volume, multiplied by the density of water at 20℃, is the density of montan wax.
1 Apparatus, materials and reagents
1.1 Guangmen pycnometer: inner diameter of about 22mm, inner height of about 70mm, with a ground glass stopper with a small hole of 1.6mm diameter (see figure). 1.2 Electric constant temperature water bath: can maintain a constant temperature of 20±0.5℃. 1.3 Analytical balance: sensitivity 0.0002g.
Drying box.
Mercury thermometer: 0～30℃, graduation is 0.2℃ (should be calibrated in advance). 1.6
Pipette: capacity is 5ml.
Evaporator with handle: 100ml.
Distilled water.
Absorbent cotton.
Qualitative filter paper.
95% ethanol (GB679-80): chemically pure, prepared into 50% ethanol water solution. 2 Determination steps
2.1 Weigh the weight of the clean and dry pycnometer (a) (weigh to 0.0002g, the same below). 2.2 Add 1ml of 50% ethanol water solution to the pycnometer along the wall of the bottle, and then add the distilled water that has been boiled and cooled to about 20℃ into the above empty pycnometer, and then place it in a constant temperature water bath at 20±0.5℃ for 30min. The water level in the constant temperature water bath should be about 1 cm below the mouth of the specific gravity bottle.
Carefully plug the bottle in the constant temperature water bath. Excess water will overflow from the capillary on the plug. At this time, it should be noted that there should be no cavitation in the capillary. Use a small strip of filter paper to absorb the water at the mouth of the capillary on the bottle plug until it is flush with the mouth. Take out the specific gravity bottle, carefully wipe off the water attached to the outer wall of the specific gravity bottle, and then weigh it (6). This value should be checked at least once a month. 2.3 Take about 40g of a representative broken wax sample and put it into a porcelain evaporator with a handle. Then put the porcelain evaporator into a drying oven at 102-105℃. Stir from time to time after the wax sample melts, keep warm for 1 hour, and then let it stand at this temperature for at least 30 minutes. 2.4 Fill a dry, pre-warmed empty pycnometer with melted wax sample to about 2/3 of its height, and then place it in a drying oven at 102-105℃ for 1 hour to allow any air that may be contained to escape (tap or shake the pycnometer to promote air removal, and stir the wax sample with a warm thin glass rod if necessary).
2.5 Cool the pycnometer containing the wax sample to room temperature and weigh it (c). Then add 1 ml of 50% ethanol aqueous solution along the wall of the pycnometer to fill the gap between the wax sample and the bottle, fill it with freshly boiled distilled water cooled to about 20℃, and then place it in a constant temperature water bath at 20±0.5℃ for 1 hour.
In a constant temperature water bath, carefully plug the bottle stopper. After the excess water overflows, there should be no air bubbles left in the capillary. Use a small strip of filter paper to absorb the water from the capillary of the bottle until it is flush with the capillary. Take out the pycnometer, wipe it dry carefully and weigh it immediately (d). National Bureau of Standards 198308-03 Issuedwww.bzxz.net
1984-05-01 Implementation
3 Result calculation,
GB3813--83
0.75~1.20
Wide-mouth pycnometer
The density of lignite wax (°20) is calculated according to the following formula: 3.1
Where: α—weight of empty pycnometer, g; 6
(h+G) -(a+d)
Weight of the pycnometer filled with water, g;
c-Weight of the pycnometer partially filled with wax, g; d--Weight of the pycnometer filled with wax and water, g; 0.9982--Density of water at 20℃, g/cm. X 0.9982
3.2 Take the arithmetic mean of the results of two parallel determinations as the determination result, and the result shall be rounded to four significant figures. 4 Allowable difference
The difference of parallel determinations shall not exceed the following provisions: Allowable (absolute)
Laboratory
Additional remarks:
Different laboratories
This standard was proposed by the Ministry of Coal Industry of the People's Republic of China and was technically managed by the Beijing Coal Chemistry Institute of the Coal Research Institute. The Beijing Coal Chemistry Institute of the Coal Research Institute of Yunnan Province and the Yunnan Coal Chemical Plant were responsible for drafting this standard. The main drafters of this standard are Ye Xianbin, Zhao Cuiying and Yan Lihua. 714
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