GB756324A - Improvements in and relating to the recovery of sugar - Google Patents

Abstract

In the extraction of sugar from sugar-containing liquor of natural origin, the liquor, after dilution if necessary, is treated e.g. at 60 DEG -62 DEG and preferably not above 72 DEG C., with a soluble aluminium compound such as the sylphate or magnesium sulphate conjointly with an alkali metal carbonate e.g. sodium carbonate, at a temperature low enough to avoid the formation of saccharates thereby precipitating and bringing down colloidal organic impurities. The aluminium compound or magnesium sulphate may be added first and the alkali-metal carbonate thereafter, the relative proportions being such that the final pH of the liquor is between 5 and 6. After separating the treated liquor from the precipitate the liquor may be bleached and then passed over cation and anion base exchanges e.g. of the synthetic resin type whereby inorganic impurities are removed and most of the sucrose is inverted. In an example 3,000 c.c. of a 25 per cent solution of blackstrap molasses diluted with slightly chlorinated water (2 p.p.m. chlorine) were heated to 62 DEG C. and 200 c.c. of 40 per cent solution of crystalline aluminium sulphate in distilled water were first added and then 100 c.c. of 19,66 per cent solution of anhydrous sodium carbonate in distilled water were added, and the liquid decanted and filtered and treated with animal charcoal. The decolourized liquor was then passed through anionic and cationic base exchangers of the resinous type, which treatment also removes those ionised particles (e.g. phosphates and ammonia) left by the animal charcoal, the liquid thereafter being concentrated in vacuo up to over 65 per cent of invert sugar.