Stone groundwood process

Mechanical Processes Stone groundwood SGW None Grinder 93-95... 

Sulfite solutions commonly are used to produce CTMP, but there are many variations of these processes. These treatments are employed to improve pulp quality. The steam and chemicals aid fiberizing by giving a less-damaged fiber, which makes the final paper stronger. The pulps are sufficiently improved over stone groundwood that they can be used to partially substitute for chemical pulps. Newsprint consisting of 100 percent TMP or CTMP is produced commercially. 

Chipping, the process of reducing a log to chips of about 2.5 x 2.5 x 0.5 cm thick is a common preliminary to all pulping methods except stone groundwood. Wood chips are more convenient and uniform for solids transport within the mill complex by conveyor belt or pneumatic delivery systems than are whole logs. Also a chip format is more amenable to direct physical conversion to fibers because of the much easier and more uniform penetration of heat and moisture through the thin sections of wood. 

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