Classification of the grades of powders

Classification of powders according to I.P

powders
Official Standards of powders

1) Course powder:

Powders of which all particles pass through a sieve with a nominal mesh aperture of 1.70 mm (No. 10 sieve) and not more than 40.0 percent through a sieve with a nominal mesh aperture of 355 μm (No. 44 sieve) is called coarse powder.

2) Moderately Coarse powder:

A powder in which all particles pass through a sieve with a normal mesh aperture of 710 µm (No. 22 sieve) and not more than 40% through a sieve with a normal mesh aperture of 250 um (60 sieve) is called “moderately coarse powder.”

3) Moderately Fine Powder:

If all the particles of a powder pass through a sieve with a nominal aperture of 355 µm (No. 44 sieve) and not more than 40.0 % through a sieve with a nominal mesh aperture of 180 µm (No. &. sieve), it falls in this group.

4) Fine powder:

In case all the particles pass through a sieve with a nominal mesh aperture of 180 μm (No. 85 sieve), it is called fine powder.

5) Very fine powder:

If all the particles of the powder pass through a sieve with a nominal mesh aperture of 125 μm (No. 120 sieve), it is said to be a very fine powder.

Also read: Principle construction, and working of ball mill

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