: MATERIA] - - . BY. 
drawn by a small lo- . .' mil] the - d iq 
an inclii s >le and drain. I I 
- Iried in tin "S 
L, and then carried to the mill- 
mill- Si . " vant "rock emery** type, and I tin 
a fine powder, in which condition it I 
: he mixer. The marl was weighed &i - I lirectly to thj 
mixer, no preliminary treatment being necessary. The avera o 
..t clay and about ~h per cent marl. 
The mixing was carried on in a mixing pan 1*2 feet in diar 
which two large roll* I in diameter and 16-inch 
iid and mixed the materials thoroughly. The mixture was 
sampled and analyzed, after which it wa> carried by a belt 
o mills, where the mixii _ - pleted and the -lurr 
• • _ 4 to I 
_ . . - iss :.g from the pug mill were cut into a numbe 
s, « s to giv< s • £ by 4 inches io -ize. Thi 
bricl - then placed on slats, which were loaded on : 
run into the drying turn - I e tunne - ted by wasl _ 
from the kilns, and from twenty-four to thirty-six hours were require- 
to dry the bri 
The bricks after drying were fed into dome kiln>. of which thei 
. . and which wen* charged with alternate la 
slurrylc I - The coke charge for a kiln wa- about 4 i 
This produce _ ' - s of clinker at each burning, thus giving 
fuel consumption of about % J ( ' per cent, a- compared with the 4 
or more required in the rotary kilns using wet material-. From I 
to forty hours were required for burning the charge. Aft* . 
ing the clinker was -hoveled out. picked over by hand, and r< 
in a Blake crusher, Smidth ball mills, and David-en tube mills. 
The cement mixture ready for burning will commonly contain fra 
74 t ~~ ' per cent of lime carbonate, or an equivalent proport 
lime oxide. Several analyses : oal cement mixture- ai- _ 
the table below. Ana; s - - 1. with its relatively high percental 
of magnesia, i.- fairly typical of Lehigh Valley practice. Analys 
i o show mixture- low in lime, while analy 
blythe best proportioned of the four, especially in 
silica and alumina plus iron. Thi> ratio, for ordinary pn 
- - oould be about ~2.d or 3 to 1. a- the cement -et- quicker ai 
has les- ultim ' si _" - : be percentage of alumina increas - 
the alumina percentage be carried too high, moreover, the mixta 
will give a fusible, sticky clinker when burned, causing trouble in A 
kilns. 
>ractice. An;. - 
-'.- No. 4 is probl; 
rd to the ratf 
. for ordinary mi: 
