SUITABILITY OF LONGLEAF PINE FOR PAPER PULP. 
19 
The yields shown in Table 6 varied from 65.7 per cent for 14.5 
pounds of total Na 2 per 100 pounds of wood to 36.8 per cent for 
72.5 pounds of total Na 2 0. The conditions indicated for cook 31 
afforded the best results with regard to both yield and quality of 
pulp produced. With the higher yields the pulps were harsh and 
had less resistance to wear. Nevertheless, wrapping papers of 
medium grades could be made from these pulps. The pulp from 
cook 30 was of good quality, with strength and wearing properties 
equal to that from cook 31, but the yield was not so high. Cooks 
43, 26, and 38 were duplicates of each other, and show the accuracy 
attained in the yield determinations. The pulps from these three 
cooks were soft and fluffy, and had poor strength and wearing prop- 
erties, due to overcooking. 
Table 6. — Effect of varying amounts of all sodium compounds on the yield of pulp. 
Weight of chips charged (bone-dry basis) pounds. . 0. 996 to 1. 007 
Water in chips per cent. . 10. 2 to 11. 5 
Causticity of liquor charge do 53. 2 to 54. 3 
Sulphidity of liquor charge do 27. 4 to 27. 9 
Initial volume of digester liquors per pound of chips (bone-dry basis) gallons. . 0. 675 to 0. 683 
Duration of cooking, total hours. . 3. 
Duration of cooking, at zero gauge pressure do 0. 1 
Duration of cooking, at maximum gauge pressure do 2.0 to 2.3 
Maximum gauge pressure per square inch pounds. . 90 
Total duration of beater treatment (at light brush only) hours. . 0, 1, or 2 
Liquor 
charge, initial concentrations. 
Chemicals charged per 100 pounds of 
chips (bone-dry basis). 
Yield of 
Cook 
No. 
crude 
(bone- 
All so- 
dium 
com- 
pounds 
as Na 2 0. 
All so- 
NaOH. 
Na 2 S. 
Na 2 S0 4 . 
NaOH. 
Na 2 S. 
Na 2 S0 4 . 
dium 
pounds 
as Na 2 0. 
dry 
basis). 
Grams. 
Grams. 
Grams. 
Grams. 
per liter. 
per liter. 
per liter. 
per liter. 
Pounds. 
Pounds. 
Pounds. 
Pounds. 
Per cent. 
40 
17.6 
8.8 
8.8 
25.5 
10.0 
5.0 
5.0 
14.5 
65.7 
39 
21.2 
10.6 
10.6 
30.7 
12.0 
6.0 
6.0 
17.4 
60.2 
31 
26.3 
13.1 
13.1 
38.1 
15.0 
7.5 
7.5 
21.7 
52.0 
30 
35.6 
17.8 
17.8 
51.3 
20.0 
10.0 
10.0 
28.9 
47.0 
43 
88.2 
45.3 
45.3 
128.3 
49.8 
25.0 
25.6 
72.5 
36.8 
26 
88.8 
44.4 
44.4 
126. 8 
50.0 
25.0 
25.0 
171.4 
37.6 
38 
88.2 
44.1 
44.1 
127.6 
50.0 
25.0 
25.0 
172.4 
36.6 
(P. L.— 138, S. L.— 3&.) 
1 The Na 2 values for cooks 26 and 38 differ mainly because of different amounts of Na 2 C0 3 which are not 
separately recorded in the table. 
EFFECTS OF SODIUM CHLORIDE. 
A few tests were made to determine whether or not the use of 
sodium chloride in conjunction with caustic soda would result in firmer 
and less fuzzy pulps, more resistant to wear, than are ordinarily pro- 
duced with the soda process. If this were possible a process might be 
developed to produce pulps similar to those obtained with the sulphate 
process without the disagreeable odors so characteristic of it. Table 7 
shows a comparison between cooks made with caustic soda alone and 
with caustic soda and sodium chloride. It is not probable that sodium 
