168 



The Philippine Jouynal of Science 



1914 



The work of the Bureau of Science on materials from Naga, 

 Cebu,* demonstrated the possibihty of manufacturing good 

 natural cement with a cementation index as high as 2.47 from 

 the available coralline limestones and siliceous clays. The coral 

 sand at Iwahig requires very little grinding. 



The Iwahig sand is a white, powdery material, consisting almost 

 entirely of comminuted coral and shells. A slight residue of 

 dark-colored grains apparently fragments of ferromagnesian 

 minerals is obtained upon panning. The greater part of the 

 sand which was used in the following experiments was taken 

 from Canagaran Beach. The sand on this beach is very clean, 

 and the deposit extends for 5 kilometers along the shore. It is 

 estimated that there is available for each linear kilometer of 

 beach about 15,000 cubic meters of clean sand above the low- 

 tide level. The remainder of the sand came from the beach at 

 Bancaobancaoan near Iwahig, where it is estimated that a quan- 

 tity of 50,000 cubic meters could be obtained by dredging in 

 shallow water. There are available, near Iwahig, at least 125,000 

 cubic meters of this sand. The physical and chemical character- 

 istics of the Iwahig sand are given in Table IV. 



Table IV. — Characteristics of dry Iwahig coral sand. 



Ultimate chemical composition." 



Constituent. 



Loss by igmition.. 



Silica (Si02) 



Alumina 



Iron oxide (R2O3) 



Calcium oxide (CaO) 



Magrnesia (MgO) 



Sodium oxide (Na20)--- 

 Potassium oxide (K2O). 

 Sulphur trioxide (SO3) - 



Chlorine (CD 



Salt (NaCl) 



Per cent. 



44.40 

 1.18 



Granularimetric analysis. 



Sieve No. 



20 



1.08 

 48.00 

 2.46 

 1.80 

 0.16 

 0.72 

 0.37 

 0.61 



30 

 40 



Size Per cent 

 of mesh retained 

 in mm. on sieve. 



0.92 

 0.56 



60 

 100 

 200 



0.47 



0.28 



0.15 

 0.07 



0.10 



0.16 

 0.20 



0.28 

 16.28 

 74.44 



Per cent 



passing 



through 



sieve. 



99.90 



99.84 

 99.80 



99.72 

 83.72 

 25.56 



" Analyzed by F. Peria, chemist, Bureau of Science. 



The data in Table IV show that the sand, in its natural state, 

 is nearly fine enough to use as ground limestone in a cement 

 factory; that the sand contains about 86 per cent of calcium 

 carbonate and 5 per cent of magnesium carbonate; and that 



Reibling, W. C, and Reyes, F. D., This Journal, Sec. A (1914), 9, 127. 



