SUGAR BOILING AND CRYSTALLIZATIOX-IX-MOTION 393 



was not tiU a little before 1900 that attention began to be paid to them in 

 the cane sugar industry, where the pioneer work was done in Java At first 

 cr\'stal]ization-in-motion was appHed to grained products. A grained 

 massecuite was discharged from the pan into a receiver and cooled for 

 severed hours in motion, \nth the result that the sugar in supersaturated 

 solution deposited on the crystals, whereas if cooled at rest this sugar would 

 separate out as ven,' fine individual cr\-stals, which would not be capable of 

 immediate recover\'. This scheme, while giving an enhanced recover}' of 

 iirst product and eliminating one or more stages in the system of repeated 

 boilings, could never avoid the necessity for boihng low-grade products 

 "with the presence of the accompanying low-grade sugars, the disposal and 

 marketing of which is so difficult. The next step, which also originated in 

 Java, was the attempt to obtain aU the sugar in one operation, and was kno^\•n 

 as the " First sugar and molasses process." To do this it would be necessary' 

 to reduce the purity of the massecuite en masse to at least 65° purity %\ithout 

 any previous separation of crystals. Accordinglj', the syrup massecuite was 

 boiled very thick and was then mixed in the pan \\ith exhausted molasses 

 until the predetermined purity of the strike was obtained. After cooling 

 in motion, if everything had gone weU, first sugar and exhausted molasses 

 resulted, a part of which were removed from process, and a part retained for 

 subsequent operations. It was, however, very hard to obtain marketable 

 sugar from these strikes, and eventuall}- the process was abandoned. After 

 much experimentation, however, schemes have since been developed whereby 

 the low products are entirely suppressed, and the juice is separated into a 

 marketable sugar and waste molasses \\ithin 96 hours of its extraction from 

 the cane. These processes are described below. Accumulated experience 

 has shown that a massecuite of 55 to 60 polarization gravity purity when 

 boiled to the proper water content and cooled in motion for about 60 hours 

 can be separated into a medium grade sugar and waste molasses. By wash- 

 ing, the crystals can be made of 96 test, but in practice no attempt is made 

 to thus treat them. 



The best method of obtaining them as marketable sugar is that de\ised 

 by Spencer at Tinguaro, in Cuba. In this scheme the crystals are dropped 

 wet from the centrifugals, mingled with molasses from a high-grade strike, 

 and pumped to the tanks wherein is the high-grade massecuite ^\ith which 

 they are cured, and \\ith the sugar from which they appear as marketable 

 product. Alternatively the sugar may be used as seed grain or be remelted, 

 either of which schemes is inferior to the one described above. In actual 

 practice one of two routines is foUowed, known as a two or a three-massecuite 

 process. 



Tuv-Masseciiife Process. — The polarization gra\ity purities selected are 

 75 for the first product and 55-60 for the second. On commencing 

 operations, a strike is boiled from s\Tup alone and separated at once into 

 crj'stals and molasses. The latter are taken back into the pan \rith s\-nip 

 in such quantit}- as to give a mixed strike of 75 purit\-. From this with 

 efficient boihng molasses of 45 purity' will result. From now on ever\'' strike 

 of s\Tup massecuite is reduced to this test b\- the addition of the circulating 

 45 test molasses. As the routine continues the 45 test molasses increases 

 in quantity, and when enough has accumulated a strike of 55-60 test is 

 boiled. This is discharged into crystallizers and cooled in motion for about 

 60 hours, when the temperature should have fallen to about 100° F. On 

 dr\ing this material it should separate into a sugar and exhausted molasses 



