146 The Forest Products Laboratory 



problem would make available many cheap woods whicli cannot now 

 be used and to a decided extent assist in overcoming the wood shortage. 



The possibility opened by the use of liquid sulphur dioxide, which 

 can be obtained from the smelters, in the manufacture of sulphite acid 

 has been a subject of much speculation, and while semi-commercial 

 scale studies have pretty clearly indicated the results to be expected, 

 it still remains for a mill scale demonstration to be made. The largest 

 source of this material is, of course, in the West, and in addition to 

 offering an outlook for an extremely ob j ectionable nuisance, it would 

 go far to eliminate the damage to which all vegetation in the vicinity 

 of a smelter producing such fumes is subjected. 



In line with the policy of conservation of by-products, investiga- 

 tions have been planned and carried out on the uses of waste sulphite 

 liquor for the production of alcohfol, binders, tanning materials, etc. 

 When one considers that approximately one-half the weight of the 

 wood is dissolved during the course of the coking treatment and ordi- 

 narily runs to waste, some idea may be gained of the immensity of this 

 problem. It may be that in time to come, the relative importance of 

 the products of pulping may be reversed, as was done in the coke in- 

 dustry. 



Hardly a sulphite mill exists but that experiences trouble with 

 "pitch", and in spite of this, but little has been accomplished along the 

 lines of pitch elimination. The laboratory equipment is too small to 

 permit a comprehensive study to be made of this problem, but analyses 

 in conjunction with changing cooking conditions will doubtless throw 

 a great deal of light on the subject. 



The study of fundamental cooking conditions in the soda and 

 sulphate processes led to the development of a modified method of 

 producing sulphate pulp. By this method decreased chemical and 

 steam consumption and increased yields were obtained, and while it 

 has been impossible to conduct an entirely satisfactory mill scale trial, 

 no doubt exists that this method is worthy of wide use. 



Although sulphate pulp is not usually considered as easy bleach- 

 ing, indications are that it can be successfully bleached, yielding a fair 

 color with a higher ultimate yield than w ood pulped by the soda or sul- 

 phite process. A pulp- and paper-making trial has just been com- 

 pleted where southern pine pulped by the sulphate process has been 

 bleached, and used to a large extent in the production of a satisfactory 



