Cooling crystallization of microfiltered raw juice and of traditional thick juice: a comparison

It is well-known that in beet sugar technology the purification of raw juice is achieved using milk of lime produced from calcium carbonate. For several years now, researchers have been trying to find alternative processes to eliminate the use of milk of lime by utilizing new technologies based on microfiltration, chromatographic separation and cooling crystallization, With the aim of giving the industry all the information necessary to make a choice, a direct comparison between the cooling crystallization of traditional thick juice and of microfiltered and softened raw juice produced in the same West European sugar factory was made. A four-stage crystallization scheme was used, Both the quality of sugar and the total crystallization yield through proper mass balances was accounted for. Whereas in case of conventional syrup one EU-No.1 and one EU-No. 2 quality sugars were obtained, only one EU-No. 2 quality sugar was obtained for microfiltered raw juice. A particular aspect taken into consideration was the morphology of the crystals obtained from these two types of juices which, of course, was related to the different non-sucrose compounds contained in them. For the cooling crystallization tests, a small pilot plant was utilized.