1296 



Canadian Forestry Journal, September, 1917 



THE USES OF WOOD PULP 



By John S. Bates 

 Superintendent Forest Products Laboratories, Montreal. 



Paper making is only one of hundred 

 purposes to which pulp is put. 



The pulp and paper industry has 

 expanded very rapidly in Canada 

 during the past ten years and it 

 appears that Canada is destined to 

 become perhaps the leading country 

 in the world in the manufacture of 

 pulp and paper products from wood. 

 This is largely because of our ex- 

 tensive natural resources of water- 

 powers and suitable tree species. It 

 is important to point out the oppor- 

 tunities and responsibilities for Cana- 

 dian engineers in this technical in- 

 dustry. The consumption of paper 

 increases so rapidly from year to year 

 in the more highly develof)ed count- 

 ries that there is no indication of 

 slackening development, at least for 

 some years to come. Canada now 

 has a total of about 90 mills many of 

 which are large and of modern design. 

 The export figures for the calendar 

 year 1916 show that pulpwood, wood 

 pulp and paper have increased to 

 nearly half of the total export value 

 (approximately $100,000,000) of all 

 forest products with the exception of 

 the small proportion of specially 

 manufactured articles. 



Woods for Pulp 

 The soft woods are the most im- 

 portant species for paper-making, 

 spruce and balsam fir accounting for 

 the bulk of the woods used with hem- 

 lock, jack, pine, tamarack and other 

 conifers coming into more extensive 

 use. Poplar and basswood repre- 

 senting the "soft hardwoods" are 

 valuable for making soda pulp and a 

 variety of hardwoods such as birch 

 and maple are used in smaller quan- 

 tity. In 1915 the total reported 

 pulpwood consumption amounted to 

 1,405,836 cords with an average value 

 of $6.71 per cord. In addition Can- 

 ada exported 949,714 cords of pulp- 

 wood, which quantity has remained 



fairly constant for several years while 

 the consumption of pulpwood in 

 Canada has rapidly increased. 



Uses for Groundwood Pulp 

 The groundwood process is the 

 simplest method of manufacture, in- 

 volving the wet grinding of pulpwood 

 blocks. In 1915 this process ac- 

 counted for 52.9 per cent of the total 

 pulpwood consumption. An import 

 ant direct use of groundwood pulp 

 is in the manufacture of wallboard 

 such as ordinary "Beaver Board" and 

 the thicker "Insulite" board used for 

 insulating cold storage rooms and 

 refrigerator cars. Fibreware, repre- 

 sented by indurated pails and tubs, 

 moulded egg cases and pressed milk 

 bottles impregnated with paraffin, is 

 composed mainly of groundwood 

 pulp. Paper pie plates are cut and 

 pressed from sheets of this pulp. 



The sulphite process is the most 

 important of the chemic"al processes 

 and in 1915 used 33.5 per cent of the 

 total pulpwood. The wood is chipped 

 and steamed in large digesters with a 

 solution of calcium (and magnesium) 

 bisulphite containing free sulphurous 

 acid, which dissolves most of the 

 lignin and other non-cellulose mater- 

 ial amounting to about one-half of 

 the dry weight of the wood. Pro- 

 duction of sulphite pulp has now 

 reached about 1,000 tons per day, over 

 half of which is used in the manu- 

 facture of paper in Canada. An im- 

 portant development is the increase 

 in manufacture of bleached sulphite 

 pulp for high-grade papers. 



Making News-Print 

 News-print paper is by far the most 

 important manufactured product in 

 the pulp and paper industry and is 

 essentially a mixture of about 75 

 parts of groundwood- pulp and 25 



