Sugar Production Process
General process information
The beet is thoroughly washed before processing to remove all traces of clay and sand.
In order to extract the sugar, the beet is first cut up into elongated slices.
Sugar is then extracted from the beet by diffusing it out with hot water. Beet slices are fed in continuously at one end and hot water at the other end. A solution of sugar emerges from one end and the exhausted beet slices emerge from the other. The exhausted beet slices, or pulp, are mixed with molasses then dried and sold as an animal feed.
The remains are referred to as the raw juice. This contains about 14% sugar and is black in color.
At the diffusion stage other substances are extracted from the beet as well as the sugar. But before sugar can be produced in a white crystalline form it is necessary to remove as many of these non-sugars as possible. This part of the process is referred to as juice purification.
The main raw materials used in the purification are lime and carbon dioxide gas which are got by burning limestone in a kiln. These substances are added to the juice causing non-sugars to be precipitated out of the solution. The solid material is then filtered off. After juice purification the juice has a light yellow color.
The purified juice is a sugar solution containing approximately 14% sugar and 1% non-sugars. Concentrating the Juice is done by boiling off water from the Juice in large vessels known as evaporators. On leaving the evaporators it contains approximately 60% sugar.
In order to turn the sugar into a crystalline form it is now necessary to evaporate still more water. This is done at a reduced temperature and pressure in large vessels known as vacuum pans. Syrup is fed to the pans and as the water is evaporated off, the crystals of sugar begin to grow. The contents are then discharged into large holding vessels known as crystallizers.
Centrifuges are used in order the separate the sugar from the syrup. The syrup is spun off and the sugar crystals remain. The wet sugar is then dried, screened, cooled and sent to large bulk storage silos.