48 PHILIPPINE AGRICULTURAL REVIEW. 



REAGENTS USED IN CLARIFICATION. 



There is a great variety of reagents at the command of the 

 sugar manufacturer, each of which has certain merits over 

 others, and all are valuable in their place when properly used. 

 It will therefore be the duty of the operator to select those 

 which best meet his individual conditions. 



It is the purpose of this article to give a brief survey of the 

 more common reagents which, under certain conditions, may 

 be used to advantage in these Islands. 



Lime. This is perhaps one of the most common and most 

 widely used of all the reagents. Since the object in view is to 

 increase the purity of the juice, it is obvious that the purest rock 

 obtainable should be used in the preparation of the lime. An- 

 other reason why a good lime should be employed, is that one 

 of the main impurities of the lime rock is magnesium, which, 

 when mixed with cane juice, becomes very troublesome in the 

 incrusting of the evaporator tubes, thus greatly lowering the 

 coefficient of heat transmission. 



Much of the lime on the market in the Philippines has been 

 made without any attempt to select pure clean limestone or 

 shells. This is not suitable for putting into cane juice, and will 

 result in a great deal of trouble whenever used in modern evap- 

 orating plants. There is, however, an abundant supply of lime- 

 stone found in various parts of the Philippines, which analyses 

 show to be almost free from impurities, and which will make a 

 most excellent lime for clarifying purposes if burned properly. 

 At present there is no modern plant for burning this rock on a 

 large scale and consequently much of the work is done in a very 

 crude and unsatisfactory manner. Most of the lime for clarifi- 

 cation, in modern sugar factories, is imported, and constitutes 

 a very heavy expense. If a lime kiln were installed in conjunc- 

 tion with some of our sugar factories, fresh and well-burned 

 lime might be made as needed. The carbon dioxide could be 

 used in the juice clarification, as is done in Java, and thus a 

 good grade of plantation sugar could easily be manufactured. 

 Any excess of burned lime might very readily be sold to other 

 factories, which now use only high-priced imported lime. 



The lime used should be of the unslaked type, and should be 

 protected from the air until a short time before using. The 

 process of preparing this consists of heating lime rock to a very 

 high temperature, in a kiln for that purpose, whereby the lime- 

 stone is broken into two component parts, expressed by the 

 following chemical equation: CaCO ;t (limestone) heated to high 

 temperature ->CaO (calcium oxide) -f CO, (carbon dioxide). 



