133
6
The remaining syrup after the first centrifugation
is transferred to the next crystallization stage,
which operates completely analogously. In this
second stage, the refined sugar is produced. In
the last step, the evaporation crystallization is
often followed by cooling crystallization in order
to separate as much sugar as possible.
mixture is formed in the first crystallizer. The
crystals are separated in a large centrifuge (1.5 t
per batch) and washed with water or steam. The
washing water is returned to the process. The
crystals thus separated are the purest type of
sugar, the so-called white sugar. High-quality
white sugar has a sucrose content of 99.95%.
. Fig. 6.21 Extraction of sucrose from sugar beets (simplified process flow diagram)
6.3 · Disaccharides