How to choose grinding media for the sanding mill
In addition to consideration of factors such as sphericity and low cost, the grinding media of the sand mill should also consider three main factors: particle size, density and chemical composition.
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Particle size
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A filter screen is provided at the exit of the sand mill, and the dispersed slurry is passed therethrough, and the grinding medium of the sand mill must be trapped, so the diameter of the beads must be larger than the diameter of the sieve holes. Experience has shown that the diameter of the grinding ball is at least half the larger than the maximum diameter of the mesh hole, otherwise the screen will often become clogged. Since the beads are inevitably worn during the grinding process, the diameter of the actually used grinding beads should be appropriately enlarged.
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????Smaller beads should be used as much as possible without clogging the mesh, as it provides more abrasive contact points, that is, as long as the beads provide energy, the pigment will disperse better.
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Density
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For the conventional vertical sand mill, the density of the dispersed beads is low, the beads sink and the tendency to sink to the bottom of the sander is less, the wear of the beads and the wear of the sander are also small, but it The resulting dispersion is also small. Therefore, for pigments with small pigments and agglomerates that are easily dispersed, beads with lower density can be used. For pigments with coarsely dispersed pigments and agglomerates, high-density beads should be used. The viscosity should be slightly higher to reduce the deposition of the beads and affect the dispersion.
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Chemical components
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For latex paint production, the commonly used grinding beads for grinding are glass beads, which are relatively transparent and not very resistant to wear and do not cause excessive wear of the sander. High-strength glass beads also show only moderate wear. The wear products of the glass beads themselves are generally invisible and non-abrasive. Most glass beads have almost the same hardness and wear rate.