Sieve analysis

A sieve analysis is a practice or procedure used to assess the particle size distribution of a granular material. The size distribution is often of critical importance to the way the material performs in use. It can be used for any type of non-organic or organic granular round materials including sands, clays, granite, feldspars, coal, soil, and a wide range of manufactured powders. It can also be used for grain and seeds.

Additional recommended knowledge

Daily Sensitivity Test

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Essential Laboratory Skills Guide

Procedure

A typical sieve analysis involves a nested column of sieves with wire mesh cloth.

A representative weighed sample is poured into the top sieve which has the widest openings. Each lower sieve in the column has smaller openings than the one above. At the base is a round pan, called the receiver.

The column is typically placed in a mechanical shaker. The shaker shakes the column for a fixed amount of time. After the shaking is complete the material on each sieve is weighed. The weight of the sample of each sieve is then divided by the total weight to give a percentage retained on each sieve.

Limitations of sieve analysis

Sieve analysis in general has been used for decades to monitor material quality based on particle size. For coarse material, sizes that range down to #100 mesh (150μm), a sieve analysis and particle size distribution is accurate and consistent.

However, for material that is finer than 100 mesh, dry sieving is significantly less accurate. This is because the mechanical energy required to make particles pass through an opening and the surface attraction effects between the particle and the screen increase as the particle size decreases. Wet sieve analysis can be utilized where the material analyzed is not affected by water. Flowing water flushes fine material through the sieve much more efficiently than shaking the dry material.

Sieve analysis assumes that all particle will be round or nearly round and will pass through the square openings. For elongated and flat particles a sieve analysis will not yield reliable results, as the particle size reported will be based on an assumption of similar sizes in three dimensions.

Additional information

When using sieve columns each sieve has a US Standard Sieve No., this number usually corresponds to mesh size, but with the coarser sizes like No. 8 to No. 18, the Sieve No. does not equally match with the mesh size. For the finer sieves like 100 M, 200 M, and 325 M the Sieve No. and mesh do match. Therefore, care must be taken to either identify a grade by Sieve No. or by mesh size, but realize one may not substitute for the other. Use of the modern opening-size system (now mandated world-wide, including the US) avoids this problem.

See also

• Soil Gradation