﻿90 RICHMOND. 



Table No. S.—Sxlpiiite digestions on Philippine woods (quick-cooking process). 



Kind of 



wood and 



experiment 



No. 



Composition of 

 liquor. 



Duration of 

 digestion. 



Maxi- 

 mum 



temper- 

 ature 



carried. 



Yield of pulp. 





Screen- 

 ings. 



Total 

 S0 2 . 



Com- 

 bined 

 SOo. 



Avail- 

 able 

 S0 2 . 



Time to 

 reach 

 maxi- 

 mum 



temper- 

 ature. 



Total 

 time. 



Un- 

 bleached. 



Bleached. 



ing 



powder 



con- 

 sumed. 



Lauan: 



] 



2 



3 . __ 



Mayapis: 

 1 



2 _ _ 



3 „ . 

 Cupang: 



1 ____ 

 2. _ _ 

 3 



Per 

 cent. 



3.6 



3.5 



3.75 



3.52 

 3.45 

 3.75 



3.6 



3 



3.75 



Per 

 cent. 



1.6 



1.2 

 1.78 



1.63 

 1.35 

 1.78 



1.2 



Per 

 cent. 



2.0 



2.3 



1.97 



1.89 

 2.10 

 1.97 



2.4 



Hours. 

 4 

 5i 

 ih 



5i 

 4i 



4 



4 

 4i 



Hours. 

 12 

 11 

 11 



°C. 

 160 

 150 

 155 



Per 

 cent. 



42.2 



44.4 



46 



47.27 

 44.75 

 46 



46.76 



49.4 

 47 



Per 

 cent. 



Per 



cent. 



Per 

 cent. 



1.8 

 1.75 



43.3 



13.4 



1 

 9 151 

 11 150 

 11 155 







42.35 



14 



1.4 



3.0 







10 

 16 

 11 



145-155 

 160 

 155 



43.02 



8.51 



1.78 



1.97 











The following conclusion are drawn from the experimental data which 

 have been tabulated and from the general appearance and feel of the 

 resulting pulps : 



A certain excess of sulphurous acid over the amount necessary to 

 form the bisulphite of the base is desirable, first, because it tends to 

 prevent the formation, and separation of the monosulphite of calcium, 

 which is extremely hard to wash out and which is liable to cause specks 

 throughout the pulp; second, it is a more economical liquor to prepare. 

 However, too great an excess of free acid is sure to produce a brown pulp 

 similar to those resulting when sulphurous acid is used alone without any 

 base being present. The liquor should contain about twice as much 

 available acid — that is, acid combined as the bisulphite of the base and 

 acid absolutely free, as is combined in the form of the mono or normal 

 sulphite. Such a liquor will allow of digestions at the maximum 

 temperature of 160° and at even higher ones, without danger of burning 

 the chips if no gas is blown off during the cooking operation. A liquor 

 of this composition will complete the cook in from ten to twelve hours if 

 the charges have previously been thoroughly steamed and four hours are 

 consumed in reaching the maximum temperature ultimately carried. 



Remarks. — The sulphite digestions were regulated entirely by the 

 temperature and no gas was blown off at any time. The chips were 

 invariably steamed before the sulphite liquor was run in, and just suf- 

 ficient liquor barely to cover the well-tamped charge was used. A heavy, 

 perforated lead disc placed on top of the wood kept all the chips sub- 

 merged. No device to induce circulation of the liquor during the boiling 



