PRODUCING SODA PULP FROM ASPEN. 



47 



Table 9. — Amounts of mechanical, soda, and sulphite wood pulps used in the United 



States. 



Kind of pulp. 



Total pulps. 



Imported pulps. 



• 19091 



18992 



19091 





Tons. 

 1,323,000 

 304, 000 

 1,200,000 



Per cent. 

 4"7 

 11 

 42 



Tons. 

 586, 374 

 171, 959 

 416, 230 



Per cent. 

 50 

 15 

 35 



Tons. 

 119,500 

 9,500 

 172, 400 



Cost. 



$2, 723, 000 





398, 000 





8, 142, 000 







Total 



2, 827, 000 



100 



1, 174, 563 



100 



301,400 11.263.000 







' 



1 Bureau of the Census— Paper and Wood Pulp Statistics; preliminary report for 1909, issued Apr. 26, 

 1911, p. 3. 



2 Bureau of the Census— Bulletin 99 of the Twelfth Census, pp. 10, 12, 1901. 



RECORDS OF THE SERIES TESTS. 



Tables 10 to 14 give the data for the several groups of tests in which the cooking 

 conditions were varied in series. 



EXPLANATION OF DATA. 



The following column headings may need explanation: 



Water in chips. — The quantity of water or moisture in the chips as charged is ex- 

 pressed in percentage of water based on the calculated bone-dry weight of the chips. 



Initial concentrations of digester liquors. — The caustic soda (NaOH) and the sodium 

 carbonate (Na 2 C0 3 ) concentrations are determined by analysis of the stock soda 

 solution, and are calculated on the basis of total liquid in the charge, including mois- 

 ture in the chips. The total sodium oxide (Na 2 0) is calculated from the proportions 

 of NaOH and Na 2 C0 3 , each reduced to the sodium-oxide basis. Grams-per-liter 

 concentrations may be converted into the equivalent pounds per gallon by multi- 

 plying by 0.00834. What is sometimes erroneously called percentage concentrations 

 may be obtained by dividing grams-per-liter concentrations by 10. 



Causticity of liquor. — This represents the ratio of sodium oxide in the caustic soda 

 to the total sodium oxide. 



Initial volume of digester liquors. — The digester liquors consist of the stock soda solu- 

 tion and water charged, together with the water in the chips as charged. 



Chemicals charged. — The quantities of the several chemicals charged are their dry 

 weights based on the chemical formulae indicated. 



Duration of cooking. — Compare data with figure 3. 



Apparent condensation. — This is obtained by subtracting the amount of digester 

 liquors at the start of the cook from the amount of liquid in the digester (as read from 

 a water gauge) just before relieving the pressure, and blowing the digester at the end 

 of the cook. It affords a rough measure of the amount of water condensing from the 

 steam used for cooking. 



Yields. — The yields of total crude pulp, screenings, and screened pulp are calcu- 

 lated to a bone-dry basis, and are expressed as a percentage of the calculated bone- 

 dry weight of the chips. The total crude pulp is the total fibrous material and un- 

 cooked chips blown from the digester. 



Yields of pulp per solid cord. — In calculating yields to pounds per cord of wood a 

 "solid cord" is considered equivalent to 100 cubic feet of solid wood, green volume, 

 knot free. For the aspen tested, the calculated bone-dry weight per " solid cord " was 

 2,668 pounds. The yield of bleached pulp, which is given on the air-dry basis (10 per 

 cent moisture), is computed by deducting the loss on bleaching and considering 90 

 pounds of bone-dry pulp equal to 100 pounds of air-dry pulp. 



