3128 Chapter 25 



pulp in southern United States, i.e., 31.4 million tons. Production of these 

 semichemical and coarse-fiber pulps doubled between 1960 and 1973 at a 

 growth rate of 5.8 percent annually. Products made from these pulps were 

 mainly corrugating medium (i.e., nine-point) and fiberboard (hard-board, me- 

 dium-density fiberboard, and insulating board). There was also a small produc- 

 tion of roofing and other felts. 



Production trends in the manufacture of fiberboards made from mechanical 

 pulps are described in section 23-1 and 23-2, and by figures 29-1 1 through 29- 

 13. 



Felts for roofing, sound deadening, and other purposes were produced in 5 

 Mid-South plants and 2 Southeast plants having total daily capacities of 234 tons 

 and 100 tons in the two regions in 1974. These felts are made primarily of coarse 

 mechanical pulps. 



From 1967 to 1973, southern production of semichemical paperboard grew 

 over 50 percent, for an annual increase of about 7.3 percent (table 25-12). In 

 1973 about 2.2 million tons of semichemical paperboard were produced in the 

 12 southern states, comprising 12 percent of all paperboard manufactured in the 

 South. 



Daily capacity of semichemical plants in 1977 was less in the six Mid-South 

 states (9 plants) than in the six Southeastern states (1 1 plants), totaling about 

 2,400 and 3,700 tons respectively. 



Two semichemical processes are particularly applicable to southern hard- 

 woods, i.e., the neutral sulfite semichemical (NSSC), and green liquor semiche- 

 mical (GLSC) processes; see table 25-13 for a comparison of the two processes. 

 In Schroeder's (1976) survey of southern pulp mills, 17 produced NSSC pulp 

 with yields of 63 to 80 percent (average 74.5 percent), all for use in corrugating 

 medium; one mill was using the GLSC process, with interest expressed by 

 several others. 



Table 25-12. — Semichemical paperboard production and total paperboard production 

 in the southern United States (McGovern and Auchter 1 976) 



Year Semichemical Total 



Thousand tons/year 



1967 1,415 12,333 



1970 1,675 15,197 



1971 1,854 15,905 



1973 2,166 18,040 



1974 2,122 17,464 



