THECUBAREVIEW 25 



THE MANUFACTURE AND USE OF LIME FOR CANE 

 LANDS AND SUGAR MANUFACTURE 



By Cleve W. Hines, M. S., Sugar Tcchnolouist. 



Lime hus been mimifactureil on a rather small sc.ilc in the Pliilippine Islands since time 

 immemorial. This prothu^t, nevertheless, has invariably been of a low grade, due largely to the 

 hick of attention in selecting siiitaV)le carbonate rocks as well as to the very crude systems 

 employed in l)m-ning the lime. 



For the most jiart no kilns were used at all in this work until recently, or if a sort of kiln 

 were employed, it consisted only of a small vertical shaft near the side of a hill and quite often 

 this was not even lined with heat-resisting material. The usual system of burning the lime 

 consisted of piling up a small amount of wood in a shallow excavation which was later covered 

 with the shells or other forms of lime rock and the whole carefully covered with earth. In order 

 to have a free circulation of air for the combustion of the fuel, hollow bamboo tubes were 

 inserted in a vertical ])osition at the top as well as others in a horizontal ])08ition near the base 

 of the cone-shaped heap. 



The lime manufactured by these crude methods answered very well for the making of 

 mortars for ordinary building purposes, and the sugar planters were even content to use this 

 low-grade material in clarifying their cane juices, but with the advent of modern methods in 

 sugar manufacture the poor grades of Ume were no longer acceptable in this work. It was 

 therefore necessary for these factories to secure their lime from abroad. Accordingly, many 

 tons of high-grade lime were imported into the Islands each year for use in the factories. It 

 is interesting to note that after seeing the results of the use of a good grade of Ume in the mod- 

 ern factories even the muscovado factories have found it more desirable to \ise the high-grade 

 material in the clarification of their juices, although it costs more than the low-grade product, 

 since a better sugar is obtained. 



The price of imported Ume as well as the freight thereon has gradually advanced during the 

 past several years until this material is now an item of importance to the sugar producer. With 

 a view to reducing this unnecessary expense many planters in the sugar-producing provinces 

 are looking forward to the production of high-grade lime locally. 



There is no good reason why any lime should be imported into the Islands since the 

 extensive deposits of calcium carbonate here are ample to supply all the requirements of the 

 Islands for ii long time to come as well as to provide material for export. 



The use of lime on cane-sugar plantations covdd ill be dispensed with since it fills a very 

 important place in both the field and factory. Its effect on growing cane is observed from the 

 time the young cane is starting until the crop is harvested. In this connection, it forms a 

 necessary plant-food material, sweetens the soil, improves its condition for the development of 

 soil bacteria and improves its mechanical condition, as well as performing various other func- 

 tions which will be discussed later. 



The principal use to which lime is put in the sugar factory is in the precipitation of im- 

 purities contained in the juice subsequent to its concentration. There are few systems of 

 clarifying juices which do not employ tliis reagent. One of the latest systems devised for 

 clarifying juices removes practically all of the sugar, even from the molasses, with no other 

 reagent than the constituents of lune rock, namely, calcium oxide and carbon dioxide. In addi 

 tion to its important use as clarifying reagent, tliis material serves as an excellent germicide- 

 keeping down bacterial infection throughout the factory. 



Occurrence 

 The element calcium is a mineral which is very active in its pure state, and therefore it 

 never occurs in nature in this condition. It readily combines with oxygen and other elements 

 forming the various comiwunds, many of which are extremely stable. When the oxide combines 

 with carbon dioxide, hme rock is found. This occurs in various stages of purity depending 

 largely upon its derivation. The extremely pure crystalline form known as calcite or Iceland 

 spar is a special primistic crystal extensively used in making Nicol prisms for polariscopes. 



