over with the distillate during steaming. Mechani- 

 cal losses in handling the liquors and in analysis 

 are also involved in this figure. The main dis- 

 crepancy seems to be due to decomposition occa- 

 sioned by the alkali in dissolving the more or less 

 complex resinous content of the wood. 



TABLE 3 

 Soda Cooks for Pulp 



Experiment Number. 



1 2 3 4 5* 6 7 8x 



Ratio of Liquor to Wood.. 7.5 14.0 6.7 13.5 8.16 9.6 10.0 5 

 Ratio of Na2O to Wood-% 24 28 27.9 35.0 19.8 16.5 18.1 18.5 

 Strength of Alk. Liquor 



% Na20 3.2 2.0 4.172.6 2.421.721.8 3.7 



Causticity of Alkali-% 94.3 94.8 81.0 94.5 96.0 94.5 



Time at 100 Pounds 



Pressure Hours 2.254.0 3.5 3.252.752.5 2.753.0 



Turp. Recovered 



Gals, per Cord 2.0 0.3 000 2.932.6 



Yield of Pulp on Dry Basis 



% of Resinous Wood ... 22.5 22.3 22.8 25.2 25.9 27.0 24.0 

 Yield of Pulp on Dry Basis 



% of Actual Wood ... 41.5 41.0 41.8 46.4 47.7 49.7 44.2 



*Black Liquor from Preliminary Extraction used as Cooking Solution 

 Soda Cook on Smaller Chips. 

 xDirect Soda Cook of Resinous Chips. 



Production of Pulp 



The more pertinent data on the soda cooks have 

 been assembled in Table 3. For the sake of con- 

 venience, caustic soda was used in reducing the 

 wood to pulp. In Expt. 5 the solution used for 

 cooking was the black liquor from the preliminary 

 extraction of rosin, which had been strengthened 

 with caustic soda to salt out most of the resinate. 

 The sulphate process would have yielded better 

 fibre, but in these investigations there seemed no 

 necessity of complicating the treatment by the 

 addition of sodium sulphide. 



In the first seven experiments, the chips which 

 had been subjected to alkali extraction and washing 

 were used as raw material. In Expt. 8 a single 

 steaming of the wood was employed. The pressure 

 was held at about 30 pounds for 3 hours in order 

 to disintegrate the rosin and to distil the turpentine 

 without decomposition thereof. The pressure was 

 then raised to 100 pounds for final pulping. 



The first two ratios liquor/ wood and Na20/ wood 

 are based on the dry weight of the extracted 



46 



