CONTROL OF DECAY IN PULP AND PULP WOOD 
17 
Even though the equipment used in this instance is not comparable 
with mill equipment, the results show the relative effect of decay 
upon this type of loss. 
PREPARATION OF SULPHITE PULP 
Both sound and decayed spruce, hemlock, and aspen were cooked 
by the sulphite process in the laboratory digester, imder conditions as 
nearly uniform as possible. In Table 3 are indicated the conditions 
of cooking and the respective yields. The data on cooks Nos. 351 
and 336, of sound aspen and sound spruce, respectively, were taken 
from the laboratory records of previous tests and were used for 
purposes of comparison. 
Table 3. — Sulphite cooks of sound and decayed woods 
[Yield percentages are based on oven-dry weights of wood and pulp] 
Bleach 
Sample 
No. 
Cook 
No. 
Pulp 
No. 
Description 
Time 
of 
cook 
Max. 
temp. 
Total 
SO 2 
Free 
SO 2 
Com- 
bined 
SO 2 
Yield 
of 
crude 
Yield 
of 
screen- 
Yield 
of 
screened 
(35 p.ct. 
avail- 
able 
pulp 
ings 
pulp 
chlor- 
ine) 
Hours 
°C. 
P.ct. 
P.ct. 
P.ct. 
P.ct. 
P.ct. 
P.ct. 
P.ct. 
336 
2540 
Spruce, sound 
8.25 
153 
5.86 
4.56 
1.30 
47.1 
0.4 
46.7 
14 
~~~2545~ 
7 
2547 
Spruce, decayed... 
8 
152 
5.34 
4.10 
1.24 
44.6 
.8 
43.8 
14 
2560 
8 
560A 
do 
8 
155 
5.50 
4.37 
1.13 
47.4 
.6 
46.8 
16 
2560 
10 
560 
do 
8 
153 
5.50 
4.35 
1.15 
45.9 
.8 
45.1 
16 
2546 
6 
2548 
do 
8 
152 
5.45 
4.28 
1.17 
43.9 
.4 
43.5 
14 
2541 
9 
2555 
do.... 
8 
153 
5.56 
4.45 
1.11 
39.6 
1.2 
38.4 
20 
2554 
4 
554 
Hemlock, sound... 
8 
153 
5.38 
4.36 
1.02 
46.6 
.5 
46.1 
36 
2542 
2 
542a 
Hemlock, decayed. 
8 
152 
5.44 
4.33 
1.11 
44.9 
.7 
44.2 
26 
2542 
3 
542b 
do 
8 
153 
4.92 
3.83 
1.09 
46.6 
.8 
45.8 
35 
2542 
5 
542c 
do 
8 
153 
5.36 
4.27 
1.09 
46.8 
.7 
46.1 
44 
351 
50 
Aspen, sound 
8.25 
152 
5.50 
4.20 
1.30 
47.5 
.1 
47.4 
12 
"""2552" 
1 
5521 
Aspen, decayed... 
7 
153 
4.28 
3.14 
1.14 
42.1 
.0 
42.1 
19 
PREPARATION OF SODA PULP 
Soda cooks were made only on decayed specimens of the three woods. 
The cooking conditions were maintained as nearly uniform as possible 
except in the case of the aspen, for which a larger amount of chemical 
was used. In Table 4 are given the cooking data. The data shown 
for cooks Nos. 109 and 228, on sound spruce and sound hemlock, re- 
spectively were taken from the laboratory records for purposes of 
comparison. 
YIELD OF PULP 
The yield of screened sulphite pulp obtained from the decayed 
spruce woods did not vary greatly from each other, except in one case, 
nor were they much lower than the yield from sound spruce. The 
exceptional yield, which was abnormally low, was that from the re- 
jected wood, No. 2541. None of the hemlock woods was sufficiently 
decayed to show a pronounced decrease in yield. The aspen pulps 
showed a lesser yield with greater amount of decay. 
523°— 25f 2 
