8 PRODUCTS FROM WASTE RESINOUS WOODS. 



EXPERIMENTAL WORK. 

 MATERIAL AND PROCESS. 



The experiments to be described were conducted with what is 

 known in the South as "lightwood," which is long-leaf yellow pine 

 that has lain in the forest until practically all the sap wood has 

 decayed, leaving the heart wood sound. Such wood is rough, full of 

 knots, and the greater part of it more or less charred from forest 

 fires. For the experiments both the freshly prepared and the steam- 

 extracted chips obtained from a steam wood turpentine plant were 

 carefully selected to represent the average wood received at the 

 plant. 



The percentage of rosin which the chips contained was determined 

 by extracting with ether and drying the extract in the water oven. 

 The fresh chips contained 18.5 per cent of rosin on the basis of the 

 water-free wood, while the chips which had been steamed at the tur- 

 pentine plant contained 19.3 per cent. The total oil recovered from 

 the black liquor was approximately 2 to 4 per cent lower than these 

 figures. 



The results are applicable only to average lightwood. Yields will 

 naturally vary with the kind of wood employed. A cord of slabs and 

 lap will yield less turpentine, rosin, or rosin oils than a cord of light- 

 wood, while freshly split old stumps will yield more; old slabs and 

 lap yield less than the fresh or green. In other words, the yields 

 differ in quantity but not in kind with the character of the wood 

 employed. The wood of long-leaf pine saw timber contains, as a rule, 

 from 2 to 6 per cent of resin and about 0.2 to 0.5 per cent of turpen- 

 tine and the short-leaf pine saw timber about the same. It would 

 probably not be profitable to attempt to recover rosin oils and 

 by-products from wood containing as little as 2 per cent of resin. 

 The value of the by-products from such wood will rarely reach $3 per 

 cord, and even in well-designed and efficient works it is doubtful if a 

 profit can be secured from them. 



The experimental cooking was done in a small rotary digester 

 holding about 4 kilograms (8.8 pounds) ; from 2 to 4 kilograms of air- 

 dry wood were cooked at a charge. Wood and dilute alkali were placed 

 in the digester, which was then rotated to insure perfect contact and 

 heated during rotations until the pressure reached 40 to 50 pounds, 

 when the digester was connected with a condenser and water and 

 turpentine distilled at the stated pressure for the time stated in 

 Table 1. The digester was then closed and again rotated for from 15 

 to 20 minutes at 40 to 50 pounds pressure and again relieved as 

 before, this procedure being repeated four or five times. The con- 

 densed water and turpentine were received in a graduated constant 

 level vessel in which the turpentine could be accurately measured 



