Different components of a mixture are separated in unrequired components from a mixture or sometimes, useful components from a mixture. order to either separate the to separate more than one useful components from mixture.
For example, grain purchased from shops can contain several impurities such as pieces of stone, husk, broken grains, etc. Thus, grain is separated from these impurities to make it edible. Similarly, after preparing tea, we strain it to remove the used tea leaves from tea.