Improvements relating to processes for regenerating decolourising resins

摘要

A bed of decolorising synthetic resin is brought to a pH value corresponding to neutrality by flushing it, after regeneration with alkali, with a solution of an ammonium salt having a weakly acid reaction, and finally with water. A filter containing 3,200 litres of resin was regenerated with 4,800 litres of a 5 per cent. sodium carbonate solution. The filter was washed with 13,000 litres of water, its pH then being in the range 11 to 12. It was then flushed with 3,000 litres of a 5 per cent. ammonium chloride solution, the pH of the liquid finally flowing out of the filter being 6. Finally, the filter was washed with 5,000 litres of water. Sugar syrup of 58 DEG Brix and having a pH of 7 was then passed through. The effluent syrup had a pH of 7.2 and was 97 per cent decolorised. There was no formation of invert sugar. The ammonium salt solution concentration is preferably 5 to 10 per cent. but may be 20 per cent. An alternative salt is ammonium sulphate. Specifications 650,706 and 698,353, [Group VI], are referred to.ALSO:A bed of decolorizing synthetic resin is brought to a pH value corresponding to neutrality by flushing it, after regeneration with alkali, with a solution of an ammonium salt having a weakly acid reaction, and finally with water. A filter containing 3,200 litres of resin was regenerated with 4,800 litres of a 5 per cent sodium carbonate solution. The filter was washed with 13,000 litres of water, its pH then being in the range 11 to 12. It was then flushed with 3,000 litres of a 5 per cent ammonium chloride solution, the pH of the liquid finally flowing out of the filter being 6. Finally the filter was washed with 5,000 litres of water. Sugar syrup of 58 DEG Brix and having a pH of 7 was then passed through. The effluent syrup had a pH of 7.2 and was 97 per cent decolorized. There was no formation of invert sugar. The ammonium salt solution concentration is preferably 5 to 10 per cent but may be 20 per cent. An alternative salt is ammonium sulphate. Specifications 650,706 and 698,353 are referred to.