BULLETIN No. 620 #3 
Contribution from the Forest Service 
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SxA,2 
HENRY S. GRAVES, Forester 
Washington, D. C. 
PROFESSIONAL PAPER 
EFFECT OF VARYING CERTAIN COOKING CONDITIONS IN 
THE PRODUCTION OF SULPHITE PULP FROM SPRUCE. 
By S. E. Lunax, Chemist in Forest Products. 
——aas 
CONTENTS. 
Page. Page. 
Purpose of the experiments. -..............- 1 | Effect of varying the ratio of free to com- 
Piersuiphiteyprocesse-ee cies a: - 6 = 2-2 ees 2 bined SO, or the amount of lime in ‘the 
Kandstomwoodsused ss. asses ees. -ces- 2 ae 3 cooking liquonseeee: eee pai ea 14 
Present methods of operation................ 4 | Effect of varying total sulphur dioxide..._... 18 
HLAIMOLbeStS Se ee ae eee je leeches eis. 5 | Effect of varying the temperature of cooking. 19 
ANSORTENIS s c'o. e505 6505 Se Lau One Ona ee 5 | Summary of results. ...... Pee Seale Se 21 
Method of conducting experiments.......... 7 | Methods of analysis and other tests........-- 22 
Analysis of cooking liquor....... pete oes = 22 
March 14, 1918 - 
PURPOSE OF THE EXPERIMENTS. 
Forest products investigations of the Forest Service include the 
study of problems connected with the manufacture of pulp and paper 
from wood, so as to utilize waste material from the lumber and other 
industries wherever possible, to°increase the efficiency of present 
methods of making pulp, and to determine the practicability of making 
pulp from woods hitherto little used or considered unfit. Bulletins 
have been issued on the soda, sulphate, and ground-wood processes 
showing the effect which the different fundamental variables have on 
the resultant pulp. This bulletin supplies similar information for 
the sulphite process, and shows what effect the amount of combined 
sulphur dioxide (SO,), the total sulphur dioxide, and the temperature 
have upon the color of the paper, the duration of the cooking period, 
the yield of pulp and screenings, and the consumption of bleach. 
‘The original patent for the making of sulphite pulp states that it 
can be produced with or without the addition of a base to the 
cooking liquor but that a lighter product can be obtained when a 
NotE.—Acknowledgement is made to Mr. O. L. E. Weber, formerly of the Forest Products Laboratory, 
and Dr. Otto Kress, in charge of the section of pulp and paper, Forest Products Laboratory, for many 
valuable suggestions and much helpful advice. 
14646°—18—Bull, 620-——1 
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