PHILIPPINE RAW CEMENT MATERIALS. 229 



consider that the particles of ash are of the same volume as the particles of coal, 

 and yet only one-tenth their weight, for when the coal burns it leaves its ash 

 in the form of a skeleton. These particles of ash are already in motion and 

 are in the full draft. The gases have a velocity of at least 600 meters per 

 minute, which is quite sufficient to carry the particles up the chimney. It seems 

 probable in view of these facts that what ash does contaminate the clinker comes 

 from the impinging of the flame upon the material in the kiln." 



The sulphur content in nearly all of the Philippine coals which have 

 been analyzed by the Bureau of Science would not be injurious were 

 it accepted as a fact that all of it is absorbed by the cement clinker. The 

 other constituents of the ash may be incorporated into the cement clinker 

 by proper fluxing. When one-half of these are lost to the stack, the 

 additional amount of raw material which must be added is small. It is 

 probable that if the coal is ground to a sufficient degree of fineness the 

 ash particles will be almost entirely swept out of the kiln by the draft 

 and the factor of the ash will become very small. 



There remains the question of the heating value of the coal. The 

 average of 51 samjDles of Fairmont coal ^' which has been considered 

 above as a fuel for burning cement, shows the following analysis and 

 calorific value: 



Water 1.43 



Volatile combustible matter 37.47 



Fixed carbon 53.83 



Ash 7.27 



Sulphur 2.59 



Calories 7,785 



This analysis, which represents a vast territor}' and perhaps the best 

 American fuel for cement kilns, when calculated to the dry coal would 

 have a calorific value of about 7,900 calories. Other coals of less calo- 

 rific value have been satisfactorily used as a fuel for burning cement. 

 The Philippine coals, the analyses of which are given in the table on 

 page 227 when calculated to the dry coal would have a calorific value of 

 about 7,090, 7,110, 6,800, 5,715 and 6,715, respectively, while that of 

 the Australian coal would be 6,775 calories. Wlrile the fuel value of the 

 Philippine coals is not as great as the well-known gas coal of Fairmont, 

 West Virginia, our coals appear to be as good under these conditions 

 as any at present available in the Philippines and neighboring countries 

 and I am of the opinion that they will be very useful as a fuel for burning 

 cement. 



■"Report of the Oeol. Sw. W. Va. (1903), 2, 231. 



