PHILIPPINE RAW CEMENT MATERIALS. 213 



Table I. — Analyses of shales and limestones from Batan Island. 



Depth in meters 



Silica (SiO;) 



Alumina (ALOa)" 



Ferric oxide (FejOs) 



Ferrous oxide (FeO) 



Lime (CaO) __ 



Magnesia (MgO) 



Soda (Na«0) 



Potash (K.O) 



Loss on ignition c 



Water below 110° 



Titanium oxide (TiO.) 



Sulphuric anhydride (SO^). 

 Sulphur (S) 



Manganese (MnO) 



Correction 



Total _-. 

 Less 0=S.-, 



Total. 



1.8-48.1 



57.2-61.8 



42.72 



17.231 



2.13 



4.11 



11.12 



3.65 



0.87 



1.44 



■115.58 



1.85 



'>Ab0Te. 



None. 



0.44 



101. 14 

 0.22 



100.92 



35.02 



13.21 



2.13 



3.49 



17.44 



2.84 



1.29 



0.68 



"17. 50 



5.31 



0.77 



None. 



0.61 



Trace. 



100. 29 

 0.31 



114-133 



34.80 



11.70 

 2.69 

 3.47 



17.19 

 2.84 

 L46 

 0.80 



17.19 

 4.90 

 0.95 

 None. 

 0.61 

 0.09 



■' 1. 45 



100. 14 

 0.31 



Lime- 

 stone. 



0.97 

 0.56 

 0.25 

 0.11 

 53.86 

 0.19 



0.16 



43.18 



0.30 



=^ Includes possible phosphoric anhydride (P2O3). 



I" Includes titanic oxide (TiOn). 



<^ A number of chemical changes are involved in this factor including both losses and 

 gains, and the amount of these depends largely on the temperature employed. With the . 

 crucible covered and a moderate heat, carbon dioxide, water and carbonaceous matter 

 are entirely driven off, the sulphides are oxidized to sulphates and all the sulphur is 

 retained as sulphates by the calcium. With continued heating at a slightly higher tem- 

 perature all of the iron is oxidized. With intense heat the sulphates are gradually 

 decomposed with the ultimate loss of the entire sulphur and the alkalies are volatilized. 



"1 Ignited so that very little if any oxidation occurred. 



*> For the oxidation of the sulphur and ferrous iron on ignition. 



About two years ago, W. A. Aiken proposed 

 Lehigh district cement as follows : 



Minimum silica (SiO.) 

 Maximum alumina (AUO3) 

 Maximum iron (Fe-^Oi) 

 Lime (CaO) 

 Maximum magnesia (MgO) 



a theoretical analysis for 



Per cent. 

 21 



3.251=12-25 



62.5-63.25 



3.0 



In order to confirm this theoretical analysis, Mr. Aiken " made very thorough 

 tests on fourteen brands of Portland cement in the laboratory of the New York 

 Subway Construction. Eight of these brands showed an average analysis prac- 

 tically in agreement with the theoretical one; the remaining six failed to comply 

 with the minimum silica and three of these failed to comply with the theoretical 



= Concrete, 8, No. 2, 33 to 34. 



