Views: 1 Author: Site Editor Publish Time: 2022-01-30 Origin: Site
1 the specific gravity of grinding medium is different from that of grinding medium. From the perspective of crushing, it seems that large proportion of grinding medium is beneficial to improve grinding efficiency, which is not the case in practice. At present, the specific gravity of the grinding medium used in industry is in the large range of 2.2-14. Selecting the grinding medium with appropriate specific gravity plays a positive role in improving the grinding efficiency. The ratio is large and the energy consumed is also large. The mechanical energy between grinding media is converted into a large amount of heat energy, which increases the slurry temperature, which intensifies the Brownian movement of particles, resulting in the re agglomeration of ground particles and reduces the grinding efficiency. In addition, the grinding medium with large ratio causes serious uneven radial and axial energy density of the sand mill, which also affects the product quality. According to the author's experience, glass beads or ceramic beads with a specific gravity of 2.3-2.8 can be used as general materials. Of course, zirconia beads with high specific gravity are needed to disperse and crush hard materials with high viscosity.
2 sphericity of grinding medium spherical grinding medium has its own rotation while rotating with the blade
The total kinetic energy is: T = 1 / 2mv2 + 1 / 2jw2
Where: T - total kinetic energy of grinding medium;
M - quality of grinding medium;
V - movement speed of grinding medium;
J -- moment of inertia;
W -- angular velocity of plane motion grinding medium.
In the formula, 1 / 2jw2 is the additional energy generated by the rotation of the grinding medium, resulting in the crushing effect of particle shear and friction. Obviously, the greater the rotation speed W, the greater the additional energy generated. When the sphere is uneven, the rotation motion is blocked, which reduces the additional energy and is not conducive to grinding.
3 surface finish grinding medium and slurry are mixed and loaded into the grinding chamber. While grinding and crushing materials, the medium will also have certain wear. After the worn materials enter the slurry, it is difficult to separate them by the usual method, which will affect the product quality and even change the color of the paint, which is not expected by the manufacturer. For the same material, the wear rate is directly proportional to the surface finish of the grinding medium, so the surface of the grinding medium is required to be smooth to reduce the wear rate.
4 mechanical strength the mechanical strength of grinding medium mainly refers to the bending, compression and impact strength under normal working conditions. Generally, there is no big problem for metal grinding media, while for non-metal grinding media, it is not easy to achieve these indicators. The comprehensive requirement is that there is basically no breakage under the correct use conditions.