This standard specifies the test method for the fineness of graphite products. This standard is applicable to the fineness test of flake graphite and microcrystalline graphite products. GB/T 3520-1995 Test method for graphite fineness GB/T3520-1995 Standard download decompression password: www.bzxz.net
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National Standard of the People's Republic of China Determination method for fineness of graphite Determination method for fineness of graphite1 Subject content and scope of application This standard specifies the test method for the fineness of graphite products. This standard is applicable to the fineness test of flake graphite and microcrystalline graphite products. 2 Reference standards GB/T3518 Flake graphite GB/T3519 Microcrystalline graphite GB6003 Test sieve GB9909 Technical conditions for standard sieve oscillator for laboratory use3 Terms GB/T3520-95 Replaces GB3520-83 Sieving end point: When the sample is screened at the specified time, the screening continues for a certain period of time. When the ratio of the mass of the sieve to the sample mass is less than 0.3%, the screening reaches the end point. www.bzxz.net 4 Inspection method 4.1 Principle of the method The fineness of graphite products is expressed as the percentage of the mass of the residue or the undersize to the mass of the sample after the sample is sieved through a standard sieve with a specified aperture under certain conditions. Two methods are specified in this standard and have equal validity. 4.2 Screening method (I) 4.2.1 Equipment and instruments Rotary air flow screen: working negative pressure 20006000Pa; Standard sieve: should meet the requirements of GB6003; Electric drying oven: temperature adjustment range 0~300℃, sensitivity of the temperature controller ±1℃, balance: sensitivity 0.001g, stopwatch; f. Brush. 4.2.2 Inspection steps 4.2.2.1 Collect 200g of screening test sample according to the sampling method specified in GB/T3518 and GB/T3519. Weigh 5g of sample with moisture less than 1% (accurate to 0.001g), put it into the standard sieve with bottom, and spread the sample evenly on the sieve surface. 4.2. 2. 3 Install the standard sieve with sample on the sieve seat of the rotary airflow sieve, and pour the fine sample in the sieve bottom into the sample in the sieve, and cover it with the sieve cover approved by the State Administration of Technical Supervision on February 7, 1995 and implemented on October 1, 1995. Start the airflow sieve and start the timer at the same time, and control the working negative pressure at 2×10'Pa~3×10°Pa. Use a small wooden hammer to tap the sieve cover or sieve frame so that the sample attached to the sieve cover or sieve frame falls onto the sieve surface. Sieve for 1 minute. 4.2.2.4 Take out the standard sieve together with the sieve cover, use a brush to sweep the sample attached to the inner periphery of the sieve cover and sieve frame into the sieve, and then pour the sieve residue into a container for weighing. 4.2.2.5 Check and sieve the weighed sieve residue according to 4.2.2.3 for 15 seconds. If the sieving end point is not reached, continue sieving for 15 seconds. Repeat this process until the sieving end point is reached and perform the final weighing. 4.2.2.6 Calculation of results: The percentage of sieve residue and undersize is calculated according to formula (1) and formula (2) (keep two decimal places). m×100 a(%) = 2(%) = (1 - ±) × 100 Wherein: 1——Percentage of sieve residue, %; T2——Percentage of undersize, %, m—Sample mass, g; -Mass of sieve residue, g. Take the arithmetic mean of two test results with an absolute error of less than 2.0% as the reported data. Otherwise, re-sample the test. 4.3 Screening method (II) 4.3.1 Equipment and instruments Sieve vibrating machine: should comply with the relevant provisions of GB9909; a. Standard sieve: should comply with the requirements of GB6003; Electric drying oven, temperature adjustment range 0~~300℃, temperature controller sensitivity ±1℃, balance: sensitivity 0.01g; e. Stopwatch; f, brush. 4.3.2 Inspection steps ·(2) 4.3.2.1 Weigh 50g (accurate to 0.01g) of a sample with a moisture content of less than 1%, pour it into a standard sieve with a sieve bottom, and install it on a vibrating sieve machine for screening. The screening time is determined by the fineness of the sample. Samples mainly larger than 75μm are screened for 10min; samples mainly smaller than 75μm and larger than 45μm are screened for 20min; samples mainly smaller than 45μm are screened for 30min. 4.3.2.2 When the screening time is reached, stop the machine, pour out the material at the bottom of the sieve, and screen it on the vibrating sieve machine for 1min. If the screening end point has not been reached, continue screening for 1min. Repeat this process until the screening end point is reached. Start weighing the material on the sieve or the material under the sieve. 4.3.2.3 Calculation of results: proceed as in 4.2.2.6. Additional Notes: This standard was proposed by the State Building Materials Industry Bureau. This standard is under the jurisdiction of Shandong Nanshu Graphite Mine. This standard was drafted by Weiyang Nonmetallic Mineral Research Institute and Shandong Nanshu Graphite Mine. The drafters of this standard were Zhao Guirong and Zhan Yuchun. 276 Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.