The fineness standard of first-class fly ash mainly relates to the sieve allowance of the 45 m square hole screen. According to the national standard, the 45 m square hole screen allowance of the first-class fly ash is not more than 12%, which also means that the pass rate of 45 m should reach 88%. In the micronized powder industry, this standard is often mentioned.
In addition, for the first-class fly ash, it can also be processed by Raymond mill equipment, which can reach about 400 mesh fineness and the screening rate is as high as 90%.
As for why 45 m was used as a criterion, it is related to its equivalent of 325 mesh. Mesh is a way to express the size of the particles, the larger the mesh, the smaller the particles. The particle size of 45 m corresponds to 325 mesh, so it was selected as the criterion for judging the fineness of first-class fly ash.
In general, the fineness of the first-order fly ash is measured by the sieving allowance of the 45 m square bore sieve, which is not more than 12%, which is equivalent to the particle size of 325 mesh. This fineness standard is of great significance to ensure the quality and performance of fly ash.
However, more in-depth questions about the specific impact of the fineness of the first grade fly ash on its application performance and why 45 m was chosen as the judgment criterion may require more expertise and research to answer. Therefore, while it is not possible to elaborate on these issues here, it is hoped that the above information will provide you with some basic concepts and background knowledge about the fineness of primary fly ash.
Please note that since the fineness of the first grade fly ash involves multiple aspects and factors, in practical applications, further research and ** are required according to the specific situation and requirements. At the same time, it is recommended to consult experts in the relevant field or consult relevant literature for more detailed and accurate information for relevant professional knowledge and research.