IX, A. 1 West and Cox: Philippine Cement Raw Materials 97 



The results indicated that there is no advantage, commensurate 

 with the additional labor and expense involved, in using a 

 mixture rather than tuff alone as siliceous material. 



It is easier to obtain a satisfactory clinker from a natural 

 cement rock (argillaceous limestone) than from mixtures of 

 limestone with siliceous materials, because in the former case 

 the materials are already chemically combined. Therefore, it 

 probably would be still less difficult to burn mixtures of tuff 

 and impure limestone, such as would actually be used in cement 

 manufacture, than mixtures of tuff and pure limestone, because 

 the impure carbonate already contains a certain amount of 

 combined silicates. 



The most available limestone in the vicinity of Manila is that 

 from Binangonan. If tuff were utilized for the commercial 

 manufacture of cement, it would probably be preferable to locate 

 the plant on the Pasig River near Manila adjacent to the tuff 

 deposit and transport the limestone to the mill. 



The calculation of a cement mixture of volcanic tuff and Bi- 

 nangonan limestone would be as follows: 



According to the calculation in accordance with the formula described 

 under the discussion of Danao clay, 100 parts tuff would require 166.21 

 parts calcium oxide. The remainder of the calculation would be as follows : 



1.19 X 1.4 = 1.67 



53.78 



55.45 parts calcium oxide equivalent to calcium oxide 

 plus magnesium oxide in 100 parts Binan- 

 gonan limestone." 



1.12 X 2.60 - 2.91 



0.08 X 1.10 = 0.09 



0.07 X 0.70 = 0.05 



0.06 X 0.78 = 0.05 



3.10 parts calcium oxide equivalent to unavailable 

 elements in 100 parts limestone. 



55.45 — 3.10 = 52.35 parts calcium oxide available in 100 parts 



limestone. 

 166.21 / 52.35 = 3.175 parts Binangonan limestone required by 1 



part tuff. 



The Binangonan limestone and volcanic tuff combined accord- 

 ing to this calculation will yield the products shown in Table 

 XVI. 



" Based on analysis given in No. 18, Table II. 



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