mm 



UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 620 



Contribution from the Forest Service 

 HENRY S. GRAVES, Forester 



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 . . . 



The Sulphite Process 



Kinds of Wood Used 



Present Methods of Operation . . 



Plan of Tests 



Apparatus 



Method of Conducting Experiments 



Page 

 Effect of Varying the Ratio of Free to 

 Combined SO, or the Amount of Lime 



in the 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 Otner Tests . 22 



Analysis of Cooking Liquor ..... 22 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1918 



