Crystallization process of sugar

Crystallization is a process of formation of solid crystals precipitating from a solution through a natural or an artificial method. Crystallization is a separation process, widely applied in the chemical and pharmaceutical industry. The principle of crystallization is based on the limited solubility of a compound in a solvent at a certain temperature, pressure, etc. A change of these conditions to a state where the solubility is lower will lead to the formation of a crystalline solid.

All crystallization processes are aimed at creating a supersaturated solution or melt. The super-saturation is the driving force under whose influence new crystals are formed and present crystals grow.

Crystallization remains the preferred means of separating sugar from the impurities. As the sugar crystal is extremely selective as to what it builds into its lattice, theoretically absolutely pure crystals can be produced by crystallization.

Sugar has a very high solubility in water (solutions range from 10 to 30% water content) so solutions are very viscous. This is a significant constraint in processing. Having prepared sugar crystals, it is necessary to separate them from the mother liquor (molasses). This is carried out in high speed centrifuges.

In making icings, frostings, or candy like fondant and fudge, it is necessary to crystallize the sugar solution. For crystallization to occur, nuclei must form in the solution. To these nuclei the material of the solution is added to form crystals. Both the rate of formation of nuclei and the rate of crystallization are affected by the nature of the crystallizing substance, the concentration, the temperature, agitation, and the impurities present in the solution.
Crystallization process of sugar