Analysis of the conversion between the mesh number and particle size of precipitated barium sulfate
- 2020-04-23-

Analysis of the conversion between the mesh number and particle size of precipitated barium sulfate

Often when choosing the particle size of precipitated barium sulfate, many users do not know how to accurately judge and choose the right product. Below we will briefly explain the relationship between product mesh and particle size.

Explanation (1) The inner diameter of the sieve (μm) ≈ 14832.4/mesh of the sieve. The mesh size refers to the size of the raw material particles, which is generally expressed by the large length of the particles. The mesh size represents the size of the standard sieve. In the Taylor standard sieve, the so-called mesh is the number of sieve openings in a length of 2.54 cm (1 inch), and is referred to simply as the mesh.

Taylor standard sieve system: The division of the Taylor sieve system is based on the 200-mesh sieve size 0.074mm, multiplied or divided by the main modulus root (1.141) to the nth power (n=1,2,... .., you get a sieve size that is coarser or finer than 200. If the n-th power of the fourth root of 2 (1.1892) is multiplied or divided by 0.074mm, a series of sieves with finer divisions can be obtained. Size. The larger the mesh, the finer the particles. It is similar to the magnification of the metallographic structure. The plus or minus sign before the mesh indicates whether the mesh of the mesh can be missed. A negative number indicates that the mesh can be missed. Mesh, that is, the particle size is smaller than the mesh size; and a positive number means that the mesh cannot be passed through, that is, the particle size is greater than the mesh size. For example, the particle size is -100 mesh ~ + 200 mesh, which means that these particles can It leaks from the 100-mesh mesh but not from the 200-mesh mesh. When sieving particles of this mesh, the larger mesh (200) should be placed under the small (100) mesh. The large mesh size (200) leaves behind the particles of -100~200 mesh.

The number of meshes is the number of holes, which is the number of holes per square inch. The larger the mesh, the smaller the aperture. Generally speaking, the number of meshes x pore size (number of microns)=15000. For example, the aperture of a 400 mesh screen is about 38 microns; the aperture of a 500 mesh screen is about 30 microns. Due to the problem of open porosity, that is, because of the difference in the thickness of the wire used in weaving the net, the standards in different places are different. There are currently three E types of American standards, British standards and Japanese standards, of which the United Kingdom and the United States Similar, Japan is quite different. Our country uses the American standard, which is calculated by the formula given above. The mesh size comparison table of the American Taylor standard sieve can be found on the following web page for details.

It can be seen from this definition that the size of the mesh determines the size of the screen aperture. The size of the sieve aperture determines the Dmax of the large particles of the sieved powder. Therefore, we can see that the 400-mesh polishing powder may be very fine, such as only 1-2 microns, or it may be 10 microns or 20 microns. Because the aperture of the screen is about 38 microns.

Explanation (two)

1. The mesh refers to the number of empty holes on the screen per square inch hour. 50 meshes means that there are 50 holes per square inch hour. 500 meshes means 500. The higher the mesh number, the more holes. In addition to the perforations of the screen, it is also used to indicate the particle size of the particles that can pass through the screen. The higher the mesh, the smaller the particle size.

2. The particle size of the powder is called the particle size. Due to the complex shape of particles, there are usually several expression methods such as sieving particle size, sedimentation particle size, equivalent volume particle size, and equivalent surface area particle size. The sieve size is the size of the sieve holes that the particles can pass through the sieve, expressed by the number of sieve holes in a 1 inch (25.4mm) wide sieve, so it is called "mesh number". At present, there is no unified powder particle size technical standard at home and abroad, and each enterprise has its own definition and expression method of particle size index. In different places and industries, there are different standards for the screen specifications, so the meaning of "mesh" is also difficult to explain through the above. I hope that you can benefit a lot, and it is more clear in choosing the fineness of precipitated barium sulfate.