CHAPTER XIY. 



THE CARBONATION* PROCESS. 



The carbonation process, which is quite generally adopted in beet sugar 

 factories, has only been applied to the manufacture of cane sugar in a few 

 instances in Java and India. This process, though very successful in beet 

 factories, gave bad results when first introduced into cane sugar factories 

 owing to the presence of glucose in cane juice, this body not being a 

 constituent of sound beets. It is owing to the efforts of Geerligs and Winter 

 in Java that the process has been made even practicable, but that it will ever 

 be generally adopted is problematical. 



The essential principle of the process is the use of a large quantity of 

 lime in the clarification, giving a very copious precipitate of organic non-sugar, 

 the excess of lime being removed by the passage of carbon dioxide as an 

 insoluble carbonate. Besides precipitating organic matter, the lime acts on the 

 glucose, converting it into saccharic, glucinic, and lactic acids, the proportions 

 of each being dependent on the temperature at which reaction takes place. 



Single Carbonation. In the single process a quantity of lime 

 which, calculated as dry anhydrous lime, amounts to as much as 1 to I'd 

 per cent, of the weight of the cane is added to the juice ; carbon dioxide 

 generated by the combustion of limestone in limekilns is pumped through the 

 juice until the latter is neutral; the juice is all this time at a temperature not 

 exceeding 55 C. ; the temperature is now raised to 90 C., and the juice 

 filtered ; in some cases the juice is filtered en masse, and in others it is allowed 

 to settle and only the scums filtered. 



Double Carbonation. In the double carbonation process the juice 

 is limed as above at a temperature not exceeding 55 C., and carbon dioxide 

 passed in until the alkalinity is one represented by -05 per cent, lime ; the 

 juice is then separated from the precipitate by means of filtration, raised to 

 the boiling point, saturated with carbon dioxide, boiled for a few minutes to 

 break up bicarbonates, and again filtered. 



The point at which the passage of carbonic acid gas is stopped is indicated 

 by a clear, bright coloured juice with a rapidly settling precipitate. 



*I write 'carbonation' in preference to ' carboxatation,' as being etymologically the correct 

 iorm, although the latter spelling is adopted by Geerligs and by Ware. (W. D.) 



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