— ZACATON AS A PAPER-MAKING MATERIAL.
21
experimentally on a small scale, and doubtless in many cases this attitude is justified. Experimentation on a small scale has its own valuable sphere of usefulness, but great care should be exercised in its commercial interpretation. Therefore, with a view to giving this material a more reliable or commercial paper value the work was continued on a larger scale, more nearly under mill conditions and at a place where the services of actual mill emploj^ees could be secured for the work.
The
employed
work was of the upright stationary by 10 feet high and heated by direct steam. The cooked charge was "blown" in the regular manner into a blow pit of ordinary construction, where it was drained and washed free from black liquor. After screening in the regular manner the stock was bleached with mill bleach liquor in a beating engine and bleach chest, washed free from bleach residues, made into the desired furnish, and suitably beaten, after which it was run through a Jordan refiner and then to a Fourdrinier paper machine. The greater part of this whole work was performed by the regular digester
for this
type, measuring about 2 feet in diameter
mill employees. 1
The material used for the .four cooks of this test was dry, but had previously molded to some extent, being the same as that used in cooks Nos. 4, 5, and 6. Table shows the cooking conditions and
V
the yields of the four cooks.
Table V.
Conditions of cooking and total yields of fiber of four cooks of zacaton grass.
Cook.
Charge,
bone dry.
Pounds.
No. 7.. No. 8
Caustic
soda added.
Per
Hours under
Yield,
bone drv,
pressure.
of total fiber.
Pounds.
cent.
175 182 192 186
No. 10 o
Concentration of Cooking caustic pressure. soda.
20
41
100
19
90
90
18 16
90 90
38.6 33.4 44.6 45.2
5 6 5 6
a The charge in the digester was covered with water and heated to a steam pressure of 50 pounds per square inch for 1 hour, after which the water extract was all drained off and the residue cooked in the regular
manner.
The higher yield of total fiber in cooks Nos. 9 and 10 is due to the lower percentage of soda added and the fact that its concentration was lowered by the water remaining in the grass after extraction. The general appearance of the pulp of these four cooks was very similar; they were soft feeling, bulky, and had a very silky luster. Screening was done on a No. 10 cut screen, and in place of a pulp thickener the screened stock was run over the wet end of a Fourdrinier paper machine and taken off at the first press. This procedure left the stock in fine condition to be transferred to the bleach beater. iMuch
assistance
and information was furnished by
S.
D. Warren
&
Co.,
Cumberland
Mills,
Me.
