CANE-JUICE CLARIFICATION. 



By CLEVE. W. HINES, M. S., Station Superintendent. 



The clarification of the juice forms one of the most important 

 operations in sugar manufacture, since the higher the purity of 

 the juice to be concentrated, the greater the percentage of su- 

 crose that will crystallize, and the easier it will be to make a 

 marketable sugar. If a high-grade sugar, or even yellow clari- 

 fied sugar is to be made, this work should receive still greater 

 attention. 



Before considering the methods to pursue and the reagents 

 to use, it is well to decide first upon the grade of sugar it is 

 desirable -to make. If ordinary centrifugal sugar testing 96 

 is desired, it will usually be practical to use only lime in the 

 clarification, since in these Islands cane reaches full maturity, 

 and consequently the purity of the normal juice will be quite 

 high, sometimes as high as 90 or 92 (apparent purity). If, 

 however, it is desired to make a white plantation sugar, or gran- 

 ulated sugar, it will be advisable to subject the juice to an 

 acidifying or bleaching treatment, as well as to the lime treat- 

 ment. Usualy sulphurous acid is used for this purpose, but 

 sometimes phosphoric acid, or a form of it, is employed. It is 

 generally best to administer the acidifying agent before the ap- 

 plication of the lime, since this raises the acidity and permits 

 a larger amount of the lime to be used. However, this process 

 is reversed by some manufacturers, and very good results are 

 often reported. 



In the acidifying of any cane juice, care must be exercised 

 that too high an acidity is not reached, since acids have an in- 

 verting effect upon sucrose, thus causing a noticeable loss. This 

 of course depends upon the degree of acidity carried, the tem- 

 perature maintained, and the methods followed during the time 

 the juice remains acid. 



When it is desired to make a high-grade crystal for granu- 

 lated sugar, the clarification must be more complete, and a water- 

 white thick liquor should result, without subsequent treatment 

 by bleaching agents and other chemicals, except the neutralizing 

 of the slightly yellowish tint, which will be mentioned later. 



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