This standard specifies the definition, principle, equipment and materials, test procedures, result calculation, test error and test report for the determination of bulk density, apparent porosity and true porosity of dense shaped refractory products. GB/T 2997-2000 Test method for bulk density, apparent porosity and true porosity of dense shaped refractory products GB/T2997-2000 Standard download decompression password: www.bzxz.net

GB/T 2997—2000
This standard adopts ISO5017:1998 "Dense shaped refractory products-Determination of bulk density, apparent porosity and true porosity". This standard has the following differences from ISO5017:
The conventional method and arbitration method are used for immersion test specimens; the liquid used for immersion test specimens is changed from distilled water or suitable organic liquid to self-contained water or organic liquid containing suitable organic liquid, and the provisions for test error are added.
This standard makes revisions to GB/T2997—1982 in the following aspects: the water absorption test item is cancelled;
The sample size is changed from the original maximum edge length of no more than 80mm to the ratio of the longest dimension to the shortest dimension of no more than 2:1; the method of sample diffusion is revised:
The accuracy of porosity calculation is changed from 1% to 0.1%. This standard replaces GB/T 2997-1982 from the date of implementation. This standard is proposed by the State Metallurgical Industry Bureau. This standard is under the jurisdiction of the National Technical Committee for Standardization of Refractory Materials. The main drafting unit of this standard is Luoyang Refractory Materials Research Institute. The main drafters of this standard are Zheng Xianghua, Zhang Qing and Liu Linmei. GB/T 2997-2000
ISO Foreword
TSO (International Organization for Standardization) is a joint organization of international standardization members (ISO members). International standards are usually formulated by ISO's standardization technical committees. Each member country has the right to participate in the activities of the professional technical committees of its own interest. International organizations, governments and non-governmental organizations associated with ISO can also participate in this work. ISO has a close cooperative relationship with the International Electrotechnical Commission (EC) in all aspects of electrotechnical standardization. The draft international standard adopted by the technical committee must be voted on by members, and 75% of the votes must be in favor before it can be published as an international standard. International Standard ISO5017 was formulated by ISO/TC33 Technical Committee for Refractory Materials. The revised second edition replaces the first edition (IS0) 5017:1988). 1 Scope
National Standard of the People's Republic of ChinabZxz.net
Test method for bulk density, apparent porosity and true porosity of dense shaped refractory products. GB/T 2997—2000
eqvISo5017.1998
Replaces GB/T 2997-1982
This standard specifies the definition, principle, equipment and materials, test procedures, result calculation, test error and test report for the determination of bulk density, apparent porosity and true porosity of dense shaped refractory products. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. The versions shown are valid when the standard is published. All versions are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T5071—1997 Test method for true density of refractory materials GB/T7321—1987 Sample preparation regulations for testing dense shaped refractory products GB/T8170—1987 Rules for rounding off values ​​
3 Definitions
This standard adopts the following definitions.
3.1 Bulk density (pr) The ratio of the mass of a dry material with pores to its total volume, expressed in g/cm' or kg/m\. 3.2 Total volume (V,)
The sum of the volumes of solid matter, open pores and closed pores in a porous material. 3-3 True density (o)
The ratio of the mass of a dry material with pores to its true volume, expressed in g/cm\ or kg/m\. 3.4
True volume
The volume of solid matter in a porous material. 3.5Open pores
Pores that can be filled with liquid when immersed.
Closed pores
Pores that cannot be filled with liquid when immersed. 3-7
Apparent porosity (π.)The ratio of the volume of all open pores in a porous material to its total volume, expressed in %. Approved by the State Administration of Quality and Technical Supervision on November 17, 2000 and implemented on June 1, 2001
3.8Eloged porosity ()GB/T 2997-2000
The ratio of the volume of all closed pores in a porous material to its total volume, expressed in %. 3.9 True porosity (yuan) The sum of apparent porosity and closed porosity, expressed in %. 3.10 Dense shaped refractory product dense shaped refractory product Shaped refractory product with a true porosity of less than 45%. 4. Weigh the mass of the sample, and then determine its volume by liquid static weighing method, calculate the apparent porosity and bulk density, or calculate the true porosity based on the true density of the sample (determined according to GR/T5071). 5. Equipment and materials 5.1 Electric heating T drying box: control accuracy ±6℃. 5.2 Balance: graduation value is 0.01, 5.3 Container with overflow pipe. 5.4 Vacuuming device: capable of reducing the absolute pressure to no more than 2500Pa (0.025bar), and capable of measuring the pressure used. 5.5 Dryer. 5.6 Thermometer.
5.7 Liquid specific gravity balance or hydrometer: the graduation value is 0.001g. 5 8 Diffusion liquid: tap water or industrial pure organic matter. 5.9 Immersion tank.
6 Test specimens
6.1 Number of test specimens: as specified in the technical conditions of the product or agreed upon by the relevant parties. 6.2 The test specimens shall be made into prisms or cylinders with a volume of 50cm2 to 200cm. The ratio of the longest dimension to the shortest dimension of the test specimen shall not exceed 2:1.
6.3 The cutting position of the test specimens shall be carried out in accordance with GB3/T7321. Notes
1 When it is impossible to prepare a test specimen with a specified size from the sample, the two parties may negotiate to use a test specimen with other sizes and indicate it in the report. 2 If the density of the test specimen is obviously uneven, then the position of the test specimen shall be determined by negotiation between the two parties and indicated in the report. 6.4 The appearance of the test specimen shall be flat and free of cracks visible to the naked eye. 7 Determination steps
7.1 Determination of the mass (m) of dry sample
Before weighing, the dust and fine particles attached to the surface of the sample should be brushed off, and the sample should be dried in an electric drying oven at 110 (5)℃ to a constant weight. Dry until the difference between the last two weighings does not exceed 0.1%, and cool naturally to room temperature in a dryer. Weigh the mass (ml) of each sample with an accuracy of 0.01g
7.2 Immersion of the sample
There are two methods for immersing the sample:
7.2.1 Conventional method
Put the sample in an immersion tank and place it in a vacuum container. Evacuate it until the residual pressure is less than 2500Pa. Keep the sample under this vacuum for about 5 minutes, then slowly inject the diffuse liquid within about 3 minutes until the sample is completely covered, and continue to evacuate for 5 minutes. Stop the vacuum, take out the immersion tank, and let it stand in the air for 30 minutes to allow the sample to fully immerse. 6
7.2.2 Arbitration method
GB/T 2997—2000
Put the sample in the immersion tank and place it in a vacuum device. Evacuate until the residual pressure is less than 2500Pa. Keep the sample at this vacuum for 15min. Then disconnect the overflow tank from the vacuum pump. If the sample in the immersion tank is no longer degassed and the pressure no longer increases, connect the immersion tank to the vacuum pump and start injecting the immersion liquid. Within 3min, the immersion liquid covers the sample by about 20mm. After maintaining this residual pressure for about 30min, turn off the vacuum pump, take out the immersion liquid, and let it stand in the air for 30min. 7.3 Determination of the mass (m2) of the saturated sample suspended in the liquid Quickly move the saturated sample to the overflow liquid in the container with an overflow pipe. When the overflow liquid completely submerges the sample, hang the sample on the hook of the balance and weigh the mass (m2) of the saturated sample suspended in the immersion liquid, accurate to 0.01°C: Measure the immersion liquid temperature, accurate to ±1°C. 7.4 Determination of the mass of saturated sample (m.)
Take the sample out of the immersion liquid, carefully wipe off the excess droplets with a cotton towel saturated with the immersion liquid, but do not suck out the liquid in the pores, and quickly weigh the mass of the saturated sample in the air (m.) to an accuracy of 0.01g. 7.5 Determination of immersion density
Determine the density of the liquid (0 mg) at the test temperature. It can be directly determined by a hydrometer or a liquid specific gravity level, accurate to 0.001 g/cm2. If it is plain water, then, between 15℃ and 30℃, it is considered to be 1.0 g/cm2. B. Calculation of results
8.1 Apparent porosity (yuan) is calculated according to formula (1): x (%) = m × 100
8.2 Bulk density (%) is calculated according to formula (2): mi
X Pina
m, —m2
Where: Lu e —-density of the liquid at the test temperature. 8.3 True porosity (yuan) is calculated according to formula (3): (%) = × 100
Where: 0 —true density of the sample, expressed in g/cm2 Note: A. Carry out in accordance with the provisions of GB/T 5071.
8.4 Closed porosity is calculated by formula (4):
e-T-
8.5 Porosity value is accurate to 0.1%. Bulk density value is reported to 2 decimal places, and the required number of digits is processed according to GB/T8170. 9 Test error
9.1 The retest error of the same sample in the same laboratory, the same test method, and the same block of samples shall not exceed: Bulk density: 0.02g/cm;
Apparent porosity, true porosity, closed porosity: 0.5. 9.2 The retest error of the same sample in different laboratories, the same test method, and the same block of samples shall not exceed: Bulk density: 0.01 g/cm;
Apparent porosity, true porosity, closed porosity: 1.0%. 10 Test Report
The test report should include the following contents:
a) Name of the testing organization;
b) Name of the entrusting unit
c) Implementation standard;
d) Name and number of the specimen:
GB/T 2997---2000
e) If the specimen size and sampling location are different from the standard or determined by negotiation between the two parties, the specimen size and sampling location must be reported; f) Single value and average value of the test results;
multiple) Name of the immersion liquid used in the test:
h) Test personnel;
i) Test date.
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