Most of the things that we come across in our day-to-day life exist as a mixture of two or more pure substances. We need to separate these pure substances from the mixture in order to use them individually. For example, you must have noticed that we don’t use the flour bought from the vendors directly for cooking chapatti. We use certain separation techniques in order to separate the flour from the impurities attached to it. We generally use sieve plates for the separation of flour from the bran particles or other impurities. These sieve plates allow the fine flour particles to pass through the holes of the sieve plate while the bigger impurities are unable to pass through it and remain on the sieve. This method of separation of particles from a mixture based on the difference in size of particles is known as sieving. It uses sieve plates for separation of coarse particles from finer particles.
Sieve plates have meshed or perforated bottoms which allow only particles of a specific size to pass through it. The size of mesh can vary from one place to another depending upon its application. For example, sieving is also used for separation of husk and stone from wheat. Here we use sieve plates having a greater mesh size in comparison to the one used for separation of flour.
Advantages of sieving;
- Sieving is a traditional and a very easy method of separation since it doesn’t require much of your skills.
- It is a cheap method as the installation cost is very low.
- It takes lesser time in comparison to other methods of separation.
Disadvantages of sieving;
Sieving is defined as a method in which two or more components of different sizes are separated from a mixture on the basis of the difference in their sizes. Thus, it cannot separate two substances in a mixture which have the same size. For example, it cannot separate a mixture of chalk powder from flour.
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