This standard specifies the method for determining the ash content of papermaking raw materials. This standard is applicable to the determination of ash content of various papermaking raw materials. GB/T 2677.3-1993 Determination of ash content of papermaking raw materials GB/T2677.3-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Fibrous raw material-Determination of ash Subject content and scope of application
This standard specifies the method for determining the ash content of papermaking raw materials. This standard is applicable to the determination of ash content of various papermaking raw materials. 2 Reference standards
GB2677.1 Sampling of samples for analysis of papermaking raw materials GB2677.2 Determination of moisture content of papermaking raw materials
3 Terminology
GB/T 2677.3-93
Replaces GB2677.3-81
Ash content refers to the ratio of the mass of the mineral residue remaining after carbonization and burning of the sample to the mass of the sample, expressed as a percentage. 4 Instruments
4.1 Porcelain crucible (30mL or 50mL). www.bzxz.net
4.2 Electric furnace.
4.3 Temperature-controlled high-temperature furnace
4.4 Desiccator (the color-changing silica gel inside should remain blue). 4.5 Analytical balance: sensitivity 0.0001g.
5 Test steps and calculation of results
5.1 Prepare samples according to GB2677.1, then weigh 2~3g of sample (accurate to 0.0001g) and place it in a porcelain crucible (4.1) that has been pre-burned to a constant mass (while weighing another sample to determine the moisture content according to GB2677.2), first burn it carefully on an electric furnace (4.2) to carbonize it, then move the crucible into a high-temperature furnace (4.3), burn it in the temperature range of 575±25℃ until there is no black carbon in the ash, take out the crucible and cool it in the air for 5~10min, then place it in a desiccator (4.4), cool it for half an hour and weigh it, then put the crucible into the high-temperature furnace, repeat the above operation, and weigh it until the mass is constant.
Ash content 2 (%) is calculated according to formula (1):
m×100
Mass of crucible after ignition, g;
Wherein: mi
m2--Mass of crucible containing ash after ignition, g; m
Mass of absolutely dry sample, g.
(1)
Report the result as the arithmetic mean of two determinations, accurate to the second decimal place. The error between the two determinations: Approved by the National Technical Supervision Committee on Wood on March 1, 1993, 202
Implemented on October 1, 1993
For raw materials, it should not exceed 0.05%, and for non-original raw materials, it should not exceed 0.2%. 5.2 Some grass raw materials contain more silicon dioxide in their ash. When burning, the ash is easy to melt and form lumps, making it difficult to burn out the black carbon. In this case, the burning time can be extended until the ash becomes lighter. If the black carbon still cannot be burned out, the following method can be tried.
Weigh 2-3g of sample (accurate to 0.0001g) in a porcelain crucible that has been burned in advance and has a constant mass (at the same time, weigh another sample to determine the water content), use a pipette to draw 5mL of magnesium acetate ethanol solution [dissolve 4.05g of magnesium acetate Mg (Ac), ·4H,0 in 50mL of distilled water, dilute to 1000mL with 95% ethanol (chemically pure) and inject into the porcelain crucible containing the sample. Use platinum wire to stir carefully until the sample is completely wetted, wash the sample attached to the platinum wire with a very small amount of water, evaporate and carbonize on a low heat, move to a high-temperature furnace, burn in the temperature range of 575±25℃ until there is no black carbon in the ash, operate according to (5.1), and weigh until the mass is constant. At the same time, do a blank test, take 5mL of magnesium acetate ethanol solution into another porcelain crucible that has been burned and has a constant mass, evaporate to dryness on a low heat, move to a high-temperature furnace and burn in the temperature range of 575±25℃ until the mass is constant. The ash content (%) is calculated according to formula (2):
m×100
blank test residue mass, g;
where: m -
masample ash mass, g;
m—absolute dry sample mass, g.
6 Test report
The test report should include the following items:
a. The number of this national standard;
Necessary instructions for the method of use;
Any abnormal phenomena during the test,
Instructions on the operation and conditions that may affect the test results. Additional notes:
This standard is proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Paper Industry. This standard is drafted by the Paper Industry Scientific Research Institute of the Ministry of Light Industry. This standard refers to the American standard TAPPI T211 om85 "Ash in Wood and Pulp". This standard was first published in 1981.
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