PHILIPPINE FIBERS AND FIBROUS SUBSTANCES. 241 



3. According to Little, 7 the modern tendency in operating the sulphite 

 process is more toward the use of stronger sulphite liquors than formerly, 

 particularly in Sweden, where liquors carrying 5 per cent or more of 

 total sulphurous acid are being employed to advantage, the quantity of 

 pulp being improved and a better recovery of gas obtained. There is 

 also a tendency toward a shorter time of cooking and there is no longer 

 any doubt but that pulp of first quality can be produced in seven hours, 

 or even less. Of course, this means increased output from the same plant. 

 It will prove to be difficult to make the stronger liquors and to maintain 

 their strength under tropical conditions of temperature, and this fact 

 will place any attempt to manufacture sulphite pulp here at a disadvantage 

 in competition with pulp manufacture in temperate regions. Even in 

 the United States of America and in Canada, considerable trouble in this 

 respect is encountered during the summer months. Only one material 

 advantage would be possessed by pulp manufacturers under the prevailing 

 local conditions of temperature and this could be a smaller loss of heat 

 by radiation, but this gain of course applies to any chemical process of 

 cooking fibers with steam. During the winter months of the year this loss 

 is a very material item of fuel expense in temperate climates. High 

 temperatures have no deleterious effect on the liquors used in the soda 

 process. 



4. The initial expense of installation of the two processes, sulphite 

 and soda, is approximately the same if the most modern equipment is 

 purchased. If there is any difference it is in favor of the soda process. 



5. The cost of maintenance in other places is considered to be about 

 equal between the two, but in the Philippines I am inclined to think that 

 it would be less- for the soda process : First, because this method does 

 not demand quite as many skilled operators, and, second, the sulphite 

 digester linings are a constant source of trouble, whereas the improved 

 form of welded soda digesters leave nothing to be desired in this respect. 



THE SODA PROCESS OX BA1IBOO. 



It was found as the result of repeated trials with caustic soda liquors 

 under varying conditions of strength, pressure and duration of cooking, 

 that bamboo chips prepared as outlined above invariably yielded 43 to 

 45 per cent of air-dry. unbleached fiber under the following conditions: 



(a) Upright cylindrical stationary digestors. 

 (fr) Direct live-steam heat. 



(c) Fifteen to 20 per cent of 76 per cent caustic soda calculated on the 

 air-dry weight of the raw material. 



(d) A duration of cooking of four to six hours. 



(e) A maximum temperature 160° 0. (320° F.) corresponding to a steam 

 pressure of 45 kilos (90 pounds). 



7 Paper Trade Journal (1908), 46, 101. 



