SUITABILITY OF LONGLEAF PINE FOR PAPER PULP. 13 
Table 3. — Record of semicommercial tests using the soda process — Continued. 
Cook No. 
Duration of cooking. 
At zero 
At maxi- 
Total. 
gauge 
pressure. 
mum 
gauge 
pressure. 
Hours. 
Hours. 
Hours. 
3.0 
0.2 
2.5 
6.0 
.2 
5.3 
6.0 
.2 
5.5 
6.0 
, 2 
5.0 
9.3 
.3 
8.3 
4.5 
.2 
3.8 
6.0 
_ 2 
5.0 
7.0 
. 5 
6.0 
7.0 
.3 
6.0 
8.0 
.3 
7.0 
Maximum cooking 
temperature. 
Digester 
pressures 
per square inch. 
Steam 
pressure 
per 
square 
Maxi- 
inch at 
mum 
Blowing. 
digester 
gauge. 
inlet. 
Pounds. 
Pounds. 
Pounds. 
90 
40 
115 
90 
45 
115 
100 
40 
110 
100 
40 
122 
60 
40 
120 
110 
40 
142 
110 
40 
125 
100 
110 
100 
100 
115 
110 
Apparent 
conden- 
sation per 
pound of 
chips 
(bone-dry 
basis). 
102. . . 
1361.. 
144... 
149... 
150... 
151... 
152... 
176-1 2 
176-2 2 
176-3 2 
331 
331 
338 
338 
307 
361 
345 
338 
338 
338 
166 
166 
170 
170 
153 
183 
174 
170 
170 
170 
Gallons. 
0.55 
.55 
.80 
1.02 
.55 
.94 
.76 
.91 
Cook 
No. 
Caustic 
black i— 
liquor at 
end of 
cook. 
in use of 
NaOH 
Yield of crude pulp 
(bone-dry basis). 
Duration of beater treat- 
ment. 
Total. 
At light 
brush 
At stiff 
brush. 
Strength 
ratio of 
paper. 
Strength 
factor of 
paper. 
Ream 
weight of 
papers 
tested. 
102.... 
1361... 
144.... 
149.... 
150.... 
151.... 
152.... 
176-1 2. 
176-22. 
176-3 2. 
Per cent. 
Per cent. 
22.7 
41.6 
17.6 
11.2 
76.7 
57.3 
81.9 
Per cent. 
47.2 
50.9 
39.8 
44.1 
52.0 
37.6 
48.0 
48.6 
51.1 
50.4 
Lbs. per 
solid cord. 
1,676 
1,808 
1,413 
1,566 
1,846 
1,335 
1,704 
Hours. 
4.0 
6.5 
6.0 
6.5 
9.0 
6.0 
8.5 
Hours. 
2 
2 
6 
2 
5 
6 
4 
Hours. 
2.0 
4.5 
0.0 
4.5 
4.0 
0.0 
4.5 
0.43 
.55 
1.04 
1.04 
.53 
.91 
1.05 
Pounds. 
0.41 
.54 
.84 
.84 
.56 
.80 
(P. L.— 138, S. L.— 176; P. L.— 164-1.) 
i Five pounds of sodium chloride (table salt) per 100 pounds of chips were used in addition to the chemicals 
indicated. However, it will be shown later that sodium chloride has little or no effect. (See p. 19.) 
2 Shipment L-3a from Mississippi was used as the test material. Data for these three cooks have been 
published previously in Forest Service unnumbered bulletin, ''Paper Pulps from Various Forest Woods," 
by Henry E. Surface, 1912. Specimens of natural color and bleached pulps accompanied the data. 
Cook 150 afforded a yield of 52 per cent, or 1 ; 846 pounds per solid 
cord, but the quality was not so good as in the case of cook 152, the 
paper being quite weak (strength factor 0.56) with a correspondingly 
low resistance to wear. The papers resulting from cooks 144, 149, 
and 151 were all of very good quality, having high strength ratios 
and good wearing properties, but the yields were considerably lower 
than for cook 152. 
' Soda pulps from longleaf pine tend to be soft and fluffy, even when 
slightly undercooked, or chippy. Proper beater treatments will 
remedy this to some extent, but the pulp does not become so well 
hydrated nor attain the same smooth, greasy feel during beating as 
the sulphate pulps, and the resultant papers do not show the 
parchmentized effect so characteristic of the sulphate papers. On 
the paper machine soda stock runs "free," while sulphate stock runs 
"slow," provided, of course, both kinds of stock are handled simi- 
larly in the beater. 
