For some years, the problem of the elimination of the calco-carbonic purifi
cation process has been studied by using alternative technologies. Some of
them, firstly studied in the laboratory and then in pilot plants, are based
on the direct concentration, under reduced pressure and countercurrently,
of the raw juice, which is then crystallized by cooling. The raw sugar obta
ined needs to be refined in order to be turned into commercial white sugar
and such a process is based on steps of solution, filtration and recrystall
ization.
In this paper the possible application of cooling crystallization as a meth
od of beet or cane sugar purification is discussed. The cooling crystalliza
tion experiments made both under laboratory conditions and on a pilot plant
are reviewed. The authors conclude by presenting a picture of the situatio
n as regards adopting the cooling crystallization technique by taking into
account the possibility of utilizing plants which do not automatically requ
ire high investment costs. The results of laboratory tests carried out on m
icrofiltered syrups are presented and discussed.