SUITABILITY OF LONGLEAF PINE FOR PAPER PULP. 13 



Table 3. — Record of seviicommercial' teats using the soda process — Continued. 







Duration of cooking. 











Digester pressures 

 per square inch. 



Steam 

 pressure 



per 



square 



inch at 



digester 



inlet. 



Apparent 

 conden- 



Cook No. 



Total. 



At zero 



gauge 



pressure. 



At maxi- 

 mum 

 gauge 



pressure. 



Maximum cooking 

 temperature. 



Maxi- 

 mum 

 gauge. 



Blowing. 



sation per 

 pound of 



chips 



(bone-dry 



basis). 



102 



Hours. 

 . 3.0 

 6.0 

 6.0 

 6.0 

 9.3 

 4.5 

 6.0 

 7.0 

 7.0 

 8.0 



Hours. 

 0.2 

 .2 

 .2 

 2 

 !3 

 .2 

 . 2 

 '.5 

 .3 

 .3 



Hours. 

 2.5 

 5.3 

 5.5 

 5.0 

 8.3 

 3.8 

 5.0 

 6.0 

 6.0 

 7.0 



"F. . 

 331 

 331 

 338 

 338 

 307 

 361 

 345 

 338 

 338 

 338 



100 

 166 

 170 

 170 

 153 

 183 

 174 

 170 

 170 

 170 



Pounds. 

 90 

 90 

 100 

 100 

 60 

 110 

 110 

 100 

 100 

 100 



Pounds. 

 40 

 45 

 40 

 40 

 40 

 40 

 40 



Pounds. 

 115 

 115 

 110 

 122 

 120 

 142 

 125 

 110 

 115 

 110 



Gallons. 

 0.55 



1361 



.55 



144 



80 



149 





150 





151 



152 



L02 

 55 



176-12 



.94 



176-2 2 





.76 



176-3 2 





.91 









Cook 



Caustic- 

 ity of 

 black 



liquor at 

 end of 

 cook. 



Efficiency 

 tn use of 

 NaOH. 



Yield of crude pulp 

 (bone-dry basis). 



Duration of beater treat- 

 ment. 



Strength 

 ratio of 

 paper. 



Strength 

 factor of 

 paper. 



Eeam 

 weight of 



No. 



Total. 



At light 

 brush. 



At stiff 

 brush. 



papers 

 tested. 



102 



Per cent: 



Per cent. 



Per cent. 

 47.2 

 50.9 

 39.8 

 44.1 

 52.0 

 37.6 

 48.0 

 48.6 

 51.1 

 50.4 



Lbs. per 

 solid cord. 

 1,676 

 1,808 

 1,413 

 1,566 

 1,846 

 1,335 

 1,704 



Hours. 

 4.0 

 6.5 

 6.0 

 6.5 

 9.0 

 6.0 

 8.5 



Hours. 

 2 

 2 

 6 

 2 

 5 

 6 

 4 



Hours. 

 2.0 

 4.5 

 0.0 

 4.5 

 4.0 

 0.0 

 4.5 



0.43 

 .55 



1.04 



1.04 

 .53 

 .91 



1.05 



0.41 



.54 

 .84 

 .84 

 .56 

 .80 

 .90 



Pounds. 

 42 



1361... 







60 



144.... 







48 



149.... 

 150.... 

 151.... 

 152.... 

 176-1 2. 



22.7 

 41.6 

 17.6 

 11.2 



76.7 

 57.3 

 81.9 

 88. 6 



37 

 43 

 46 

 37 



176-22. 





















176-3 2. 













































(P. L.— 138, S. L.— 176; P. L.— 164-1.) 



1 Five pounds of sodium chloride (table salt) per 100 pounds of chips were used in addition to the chemicals 

 indicated. However, it will be shown later that sodium chloride has little or no effect. (See p. 19.) 



2 Shipment L-3a from Mississippi was used as the test material. Data for these three cooks have been 

 published previously in Forest Service unnumbered bulletin, "Paper Pulps from Various Forest Woods," 

 by Henry E. Surface, 1912. Specimens of natural color and bleached pulps accompanied the data. 



Cook 150 afforded a yield of 52 per cent, or 1,846 pounds per soKd 

 cord, but the quality was not so good as in the case of cook 152, the 

 paper being quite weak (strength factor 0.56) with a correspondingly 

 low resistance to wear. The papers resulting from cooks 144, 149, 

 and 151 were all of very good quality, having high strength ratios 

 and good wearing properties, but the yields were considerably lower 

 than for cook 152. 



Soda pulps from longleaf pine tend to be soft and fluffy, even when 

 shghtly undercooked, or chippy. Proper beater treatments will 

 remedy this to some extent, but the pulp does not become so well 

 hydrated nor attain the same smooth, greasy feel during beating as 

 the sulphate pulps, and the resultant papers dO not show the 

 parchmentized effect so characteristic of the sulphate papers. On 

 the paper machine soda stock runs "free," while sulphate stock runs 

 "slow," provided, of course, both kinds of stock are handled simi- 

 larly in the beater. 



