UNITED STATES DEPARTMENT OF AGRICULTURE 





BULLETIN No. 



Contribution from the Forest Service 

 HENRY S. GRAVES, Forester 



suf^^Lru 



Washington, D. C. 



PROFESSIONAL PAPER 



March 14, 1918 



EFFECT OF VARYING CERTAIN COOKING CONDITIONS IN 

 THE PRODUCTION OF SULPHITE PULP FROM SPRUCE. 



By S. E. Lunak, Chemist in Forest Products. 



CONTENTS. 



Purpose of the experiments 1 



The sulphite process ^ 2 



Kinds of wood used 3 



Present methods of operation 4 



Plan of tests 5 



Apparatus 5 



Method of conducting experiments 7 



Effect of varying the ratio of free to com- 

 bined S0 2 or the amount of lime in Ithe 



cooking liquor •. 14 



Effect of varying total sulphur dioxide 18 



Effect of varying the temperature of cooking. 19 



Summary of results 21 



Methods of analysis and other tests 22 



Analysis of cooking liquor 22 



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 (S0 2 ), 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 



