EXPERIENCE OF USING AMMONIUM BISULFITE IN EXTRACTION AT BRITISH-SUGAR

Trials were carried out using ammonium bisulphite (ABS) as a biocide i n extraction at two British Sugar factories during the 1994/1995 campa ign. It was demonstrated that bacterial activity during extraction can be controlled effectively by maintaining the level of sulphur dioxide in raw juice at 150-200 mg/kg and the extraction temperature above 70 degrees C. There was a reduction in the pressed pulp dry substance co ntent which decreased from 29.1% when formalin was used in extraction to 25.7% when ABS was substituted. There were also several incidents o f high ash sugar (>0.02%) resulting in white sugar returning for repro cessing. Analysis showed that the increase in ash was due to an increa se in the concentrations of potassium, calcium and sulphate. It was po stulated that this was due to the precipitation of a double salt of po tassium and calcium sulphate, Kalussite.