SUITABILITY OF LONGLEAF PINE FOE PAPER PULP. 9 



Table 1. — Record of semicovfimercial tests using the sulphate process — Continued. 





Chemicals charged per 100 pounds of chips (bone-dry 

 basis). 



Duration of cooking. 







Cook 

 No. 









SO2 

 com- 





All 

 sodium 





At 

 zero 



At 

 maxi- 



Maximum 



cooking 

 temperature. 





NaOH. 



NaaCOs. 



NazS. 



pounds 



as 

 NazSOa. 



NazSOi. 



com- 

 pounds 

 as NazO. 



Total. 



gauge 

 pres- 

 sure. 



gauge 

 pres- 

 sure. 







Pounds. 



Pounds. 



Pounds. 



Pounds. 



Pounds. 



Pounds. 



Hours. 



Hours. 



Hours. 



"F. 



"C. 



171 



15.0 



0.8 



7.5 



1.0 



7.5 



21.8 



3.0 



0.1 



2.8 



331 



166 



77 



20.0 



1.2 



10.0 



1.3 



9.9 



29.1 



3.0 





2.3 



331 



166 



81 



15.1 



.8 



7.5 



1.0 



7.5 



21.9 



3.0 





2.5 



331 



166 



85 



15.0 



.8 



7.5 



1.0 



7.5 



21.8 



3.0 





2.5 



331 



166 



92 



12.0 



.6 



7.5 



1.0 



7.5 



19.4 



3.0 



.25 



2.5 



331 



166 



98 



12.0 



.6 



6.0 



.8 



6.0 



17.4 



5.0 





4.3 



331 



166 



113 



20.0 



1.1 



10.0 



1.3 



10.8 



29.4 



3.0 



.25 



1.0 



331 



166 



138 



20.0 



1.0 



10.0 



1.3 



10.0 



29.0 



3.0 





2.8 



331 



166 



141 



20.0 



1.1 



5.0 



.7 



10.0 



24.8 



3.0 





2.5 



331 



166 



146 



15.0 



.8 



7.5 



1.0 



7.5 



21.8 



3.0 



.2 



2.3 



338 



170 



147 



15.0 



.7 



7.5 



1.0 



7.5 



21.8 



3.5 



.3 



2.8 



338 



170 



148 



15.0 



.7 



7.5 



1.0 



7.5 



21.8 



3.5 



.2 



3.0 



338 



170 





Digester pres- 





Appar- 





Duration of beater 











sures per square 





ent con- 





treatment. 











inch. 





densa- 





















per 

 square 



tion 











Strength 

 ratio 



Strength 

 factor 



weight 

 of 



Cook 

 No. 







per 

 pound 

 ofchips 

 (bone- 

 dry 

 basis). 



pulp (bone-dry 









Maxi- 



Blow- 



inch 

 at di- 



basis). 



Total. 



At 

 Ught 



At 

 stiff 



of paper. 



of paper. 



papers 

 tested. 





gauge. 



ing. 



gester 

 inlet. 







brush. 



brush. 





















Lbs. per 



























solid 

















Pounds. 



Pounds. 



Pounds. 



Gallons. 



Per 



cord. 



Hours. 



Hours. 



Hours. 







Pounds. 



171 



90 



40 



105 



10.20 



61.2- 



2,172 



3.5 



1.5 



2.0 



0.60 



0.50 



76 



77 



90 



40 



105 



.50 



45.3 



1,609 



3.5 



2.0 



1.5 



1.15 



.91 



31 



81 



90 



50 



103 



.58 



47.9 



1,700 



5.0 



2.5 



2.5 



1.08 



.93 



44 



85 



90 



50 



108 





52.0 



1,846 



7.0 



3.0 



4.0 



.91 



.87 



38 



92 



90 



40 



110 



.49 



48.8 



1,733 



6.5 



2.5 



4.0 



.86 



.70 



28 



98 



90 



40 



108 



.50 



51.8 



1,839 



4.5 



1.0 



3.5 



,60 



.56 



28 



113 



90 



40 



100-95 



.32 



4a 6 



1,725 



6.0 



2.0 



4.0 



.70 



.59 



37 



138 



90 

 90 



40 

 40 



110 



108 





46.1 

 44.2 



1,637 

 1,569 















141 



8.5 



4.5 



4.0 



L02 



.86 



36 



146 



100 



40 



105 





54.9 



1,949 



9.0 



4.0 



5.0 



.72 



.68 



45 



147 



100 



40 



115 



.41 



49.1 



1,743 



6.5 



4.0 



2.5 



.92 



.71 



37 



148 



100 



40 



115 



.63 



48.4 



1,718 



8.5 



4.0 



4.5 



1.02 



.77 



33 



(P. L.— 138, S. L.— 176.) 

 1 A portion of the digester liquor was lost, due to leaks during the early stages of cooking. 



SEVERE COOKING TREATMENTS. 



The effect of more severe cooking treatments, produced mainly 

 by greater initial concentrations and amounts of active cooking 

 chemicals, was evidenced by the thoroughly cooked or overcooked 

 pulps from cooks 77 and 141 (Table 1). The crude pulps were not 

 only free from chips and shives, but also seemed to be soft and 

 fluffy. The papers made from the beaten pulps, however, were of 

 very superior quality with regard to resistance to wear, toughness, 

 and strength, the strength factors being 0.91 and 0.86 for cooks 77 

 and 141, respectively. Both pulps became slightly hydrated during 

 the beater treatments, which produced a parchmentizing effect and 

 increased the strength and toughness. Either of the papers could be 

 24542°— 14 2 



