Definition - What does Sieve Analysis mean?
Sieve analysis is an analytical technique used to determine the particle size distribution of a granular material with macroscopic granular sizes. The technique involves the layering of sieves with different grades of sieve opening sizes. The finest sized sieve lies on the bottom of the stack with each layered sieve stacked above in order of increasing sieve size. When a granular material is added to the top and sifted, the particles of the material are separated into the final layer the particle could not pass.
Commercial sieve analyzers weigh each individual sieve in the stack to determine the weight distribution of the particles. The base of the instrument is a shaker, which facilitates the filtering.
Sieve analysis is important for analyzing materials because particle size distribution can affect a wide range of properties such as the strength of concrete, the solubility of a mixture, surface area properties and even their taste.
Corrosionpedia explains Sieve Analysis
Sieve analysis uses sieves of various types, depending on the sieve hole size range. A few sieve types and their nominal aperture ranges are as follows:
- Woven wire mesh sieves: 20 μm – 3.6 mm
- Perforated plate sieves: 1 mm – 125 mm
- American standard sieves: 20 μm – 200 mm
With the sieve type chosen, the actual sifting process can be carried out using various methods, such as:
- Throw-action methods involve applying a vertical force along with a circular motion to rotate granules and reorient them to pass through a sieve hole.
- Horizontal methods uses horizontal circular motions and is the preferred method for long fibrous sample types.
- Tap sieving also uses a horizontal circular motion, but adds regular vertical taps, much like sieving would be performed by hand.
- Air jet sieving uses an air stream to disturb the material during the process.
- In cases where fine powders are present that may clog the system, wet sieving may be used for the sieving process and each layer of the stack is dried and weighed in a secondary step.
After the sieving process, the percent weights of each section of the stack are analyzed by percent weight retained and then percent weight passed. From this data the distribution of granule size can be displayed graphically. The distribution, called a gradation, can be described as one of the following:
- Dense gradation
- Gap gradation
- Narrow gradation
- Open gradation
- Rich gradation
Sieve analysis works well for large granules approximately spherical in shape. Shapes that deviate strongly from spherical, such as a rod shape, or granule sizes that are very small can cause errors to occur in the sieve analysis process.