GB/T 3520-2024 "Graphite Fineness Test Method" specifies the determination method of the fineness of graphite products, which is suitable for the experimental analysis of graphite fineness. The standard includes three main test methods: negative pressure sieve analysis method, vibrating sieve machine method and laser diffraction method. The negative pressure sieve analysis method and vibrating sieve machine method are suitable for the determination of graphite fineness with particle size greater than 38 μm. Different equipment and sieve time are used to ensure the accuracy of the test. The laser diffraction method is used for graphite with particle size less than 38 μm. Accurate measurement is carried out using Laser Particle Size Analyzer. The standard also describes in detail the content of sample preparation, instrumentation, experimental steps and result calculation to ensure the repeatability and accuracy of the test.