Explain the principle and application Crystallisation

Crystallization is a technique of purifying solid materials by using a suitable solvent. It is based on the difference in the solubilites of the compound and the impurities in a given solvent. The impure compound which is sparingly soluble in a solvent at room temperature gets dissolved in the solvent​ at higher temperature. A saturated solution is made on heating. On cooling the solution, the pure compound crystallises out and is removed by filtration.
Crystallisation is widely used in pharmaceutical industry, agrochemicals, food and cosmetic industry. The ingredients used in these substances are purified by crystallization.