Daren ANNUAL REPORT 
We can, however, attack the problem from another standpoint, 
making use not of the formula, but of the percentage composition of the 
clay, which according to the above formula would be: 
Per cents. 
SiliGae nice aie ieee meas ea Che ae inte fae Ta 63.40 
PAW Hola cHl0Ys Reap eRnapEMm RR Din Cone anun ee las dre OUie eee Sot ges PAL OD 
HSrriCsO RIG 6 oie aoe scheme ie Enea ee re 7.44 
Chemicaltwater ae eee eer Re eat 2 7.61 
The limiting formula 1(3CaOSiO,)+7(2CaOAl,O,) can at once 
be translated into terms of parts by weight; since 3 molecules of calcium 
oxide are required for one of silica, we can say that 3x56=168 parts 
by weight ot lime are needed for 1X60=60 parts of silica, or for one 
part of silica 2.8 parts of calcium oxide are required. In terms of the 
carbonate (3X100)—+60=5 parts are needed for one part of silica. 
Likewise we find that one molecule of alumina requires 2 molecules of 
lime, and hence one part of alumina must have 1.1 part of lime, or 
200+102=nearly two parts of carbonate. The calculation now becomes 
very simple: 
63.40 parts of silica demand 63.4*5=317.09 parts of carbonate. 
21.55 parts of alumina demand 21.55x2= 43.19 parts of carbonate. 
360.28 
100 parts of clay demand hence 360.28 parts of carbonate or I part must 
have 3.6 parts of the limestone, which is practically the same as the ratio 
obtained in the first problem. 
The Limitations of the Chatelier Formula.—The Chatelier formula 
does not give entire satisfaction, however. For instance, taking the 
formula 
17CaAQ), 5SiIOs, ALOs, O22) (0% 
we find the percentage composition to be: 
Per cents. 
PaO eho Je oe ak re gee ae ose Soe sana Arg ee grin 68 .54 
LTC ae EN a ec ceierer Say erty are ine Oe eee a aC Soe 21.60 
PAU DUGGUE GU: We AUN IS Peace incre arty Tat apne Jon REE he de des 7.34 
Herr GhO M1 6 ce Seen Ne oats © eee ee re rare D3 
It will be noticed that the content of lime is higher than that of 
the average Portland cement. We assumed, however, that no fluxes 
were present; in using a clay with other fluxes like potash and soda 
the percentage of the calcium oxide would be reduced somewhat. This is 
due to the fact that the formula used is an ideal one, which requires ideal 
conditions of blending, that 1s, perfect pulverization which cannot be 
obtained in practice. However, it might be perfectly feasible to produce a 
‘* 
R. 
oe 
