Sieve analysis

Sieve analysis

Particle size analysis of crushed/ ground products is generally determined using a nest of sieves. Sieves used for scientific purposes are meshes with uniform apertures [openings]. Sieves are designated by mesh numbers such as 200 mesh. Mesh number is the number of apertures per linear inch. It is important to note that mesh number itself does not tell us anything about the size of the opening of the mesh as different standards use different sizes of wires that form the mesh. However 200 mesh has 74 microns aperture in all the standards. Particle size distribution of crushed/ ground products is determined using a nest of sieves. May see the following example. Ground phosphate ore weighing 100 grams has the following size analysis:

Sr. No. Size distribution in terms of aperture opening (mm) Weight % retained Cumulative weight % retained % Weight passing through
1. +125 37.20 37.20 62.80% passing through 125 microns aperture
2. - 125 +106 7.20 44.40 55.60% passing through 106 microns aperture
3. -106 +75 18.30 62.70 37.30% passing through 75 microns aperture
4. -75 +53 2.30 65.00 35.00% passing through 53 microns aperture
5. -53 +38 7.90 72.90 27.10% passing through 38 microns aperture
6. -38 27.10 100

The d80 of the above size distribution table is 187.19 microns which is estimated using Gaudin–Schuhmann equation.
May see the attachment.

[1] Question: What is mesh number. Answer: Number of apertures per linear inch in a sieve.

[2] Question: Which mesh is common in all the standards. Answer: 200 mesh

[3] What is d80 ? Answer: d80 is the size in microns through which 80% of the material passes.

[4] Explain Gaudin – Schuhmann equation .

See the attachment for answer.

[5] Explain Rosin-Rammler equation.

Find the answer in the attachment.

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