NORTHERN SUGAR INDUSTRY. 



109 



BEET -SUGAR METHOD BY SINGLE AND DOUBLE CARBONATATION FOE 

 THE DEFECATION OF SORGHUM JUICES. 



This inetliod consists .essentially in adding an excess of lime to the 

 juice, then removing the excess by a current of carbonic dioxide. In 

 the method by double carbonatation a portion of the lime is first added 

 in the cold and the excess removed, and then a second and smaller por- 

 tion of lime is added, the juice being kept at the boiling point and the 

 excess removed as before, the juice remaining neutral or slightly alkaline. 

 The proportion of lime employed depends upon the character of the 

 juice. A number of experiments has been made to determine that pro- 

 portion which gives a good, clear, pure juice, easily filtered at a reason- 

 able expense both of time and carbonic dioxide. A large number of 

 results indicates that for diffusion juices 2 per cent. CaO, and for mill 

 3 per cent. CaO. are the best proportions. 



Table Xo. 1 shows the influence of the lime in raising the coefficient 

 of purity. The coefficient of purity of diffusion juice is never increased 

 in proportion to that of the mill juice, as it contains much less of those 

 substances acted upon by the lime. After the second carbonatation the 

 results as to increase and decrease of coefficient of purity were not very 

 satisfactory. The lime assumes a combination which prevents its being- 

 removed hy the carbonic acid. This will be again referred to in dis- 

 cussing the results given under the table. The taste of the juice after 

 the first carbonatation resembles that of the sap from the maple tree, 

 but after the second it is bitter and unpalatable. The color was brown- 

 ish, due to a slight decomposition of the anoptose. This coloration of 

 the juice could be avoided on a large scale by rapid carbonatation. It 

 is easily bleached- by the use of bisulphite of lime or sulphurous acid. 



Table Xo. 2 gives the proportion of anoptose to the sucrose before and 

 after defecation. After the first defecation, i. the defecation in the 

 cold, the proportion of anoptose to the sucrose is reduced but little, 

 though enough to indicate that it is the cause of the coloring of the juice. 

 After the second carbonatation, hot, there is a \ ery marked reduction 

 in this proportion. The anoptose has evidently combined with the lime 

 forming soluble and insoluble compounds ; the soluble portion giving 

 the deep brown coloration, which the juice acquires at the second def- 

 ecation and the bitter unpleasant taste. Its remaining in solution also 

 accounts for ihe total solids not decreasing in proportion to the amount 

 of anoptose decomposed. The experiments made, show that the method 

 by double carbonatation would not be a success, practically, with the 

 sorghum juice, owing to the large amount of anoptose usually present 

 in the juices of this cane. But the method by single carbonatation is 

 very successful, inasmuch as the juice is not heated in contact with the 

 lime. 



Table Xo. 3. — It is seen from the analyses given in this table that 

 the lime has a marked effect on the nitrogenous bodies present in the 



