The experiences of three campaigns with the carbonate process are discussed. By applying this process, part of the non-sugars is transformed in ammonium- carbonate resp. ^bicarbonate, especially when thin juice is treated with ion exchange resins. By evaporation ammonia and carbonic acid are eliminated from the treated solution and partly recovered. The result is a sugar solution with corresponding lower non-sugars content.
The surplus of ammonium carbonate in the regeneration process is recovered from the regeneration solution by evaporation and the relatively small losses are made up by ammoniacal water and lime kiln gas.
The exclusive use of sodium- or magnesiumchloride for desorbing colouring matters and of ammonium carbonate as regenerant excludes the danger of inversion in the ion-exchangers. Therefore the process can be applied at about 70°C. The resulting juice is almost completely decolorized and thermostable. In the following treatment^ the advantages are a simpler boiling scheme and, an improved sugar quality.
At the Enns plant, 450 m3 of softened thin juice were treated this way in 90 minutes and about 1,5 tons of non-sugars removed and the corresponding quantity of sugar gained. By the fact that mainly alkali compounds are removed the purity of the remaining final molasses is lowered.
Details about the necessary auxiliary materials in relation to the removed non-sugars are specified.
This process can be properly adjusted to various conditions : it is, for example, possible to increase the removal of non-sugars by using additional ion exchangers.
Proceedings: CITS 1971
pdf download: CITS1971-389-409.pdf