Pulp and Paper 



3087 



Pulping processes. — In the United States, the number of mills producing 

 sulfate (kraft), semichemical, and defibrated/exploded pulps have increased 

 significantly, while the number producing sulfite, groundwood, and soda pulps 

 have decreased (fig. 25-3). 



Total U.S. annual capacity for pulp production increased in all categories, 

 except sulfite pulp, between 1960 and 1974; the major increase was in capacity 

 to manufacture sulfate (kraft) pulps (figs. 25-4 and 25-5). 



YEAR 



M 144 579 

 Figure 25-3. — Number of woodpulp mills In the United States, by type, 1920-1974. 

 (Drawing after McKeever 1977.) 



Demand for paper and paperboard. — Whitney (1980) provided (fig. 25-6) 

 a breakdown of paper production into its three principal categories of construc- 

 tion paper and board (i.e., roofing felts and insulation boards), paper, and paper 

 board; see section 25-2 for the components of the latter two categories. 



Paper production is comprised principally of tissue, packaging, and industrial 

 papers, and printing and writing papers (fig. 25-7). The latter is the fastest 

 growing segment, making up about two-thirds of paper production. The dashed 

 line at the top of figure 25-7 shows paper consumption, which runs about 7 

 million tons higher than production. Most of this difference represents imports 

 from Canada, which supplies about two-thirds of United States newsprint re- 

 quirements (Whitney 1980). 



