| 摘要 |
A process is provided which comprises the steps of: (1) grinding lignocellulosic material to form an aqueous groundwood pulp fiber suspension; (2) screening the groundwood pulp fiber suspension through a coarse screen having screen openings not less that about 5 mm; (3) defibrating lignocellulosic material separated out on the coarse screen; (4) recycling the defibrated lignocellulosic material to the groundwood pulp fiber suspension from the grinding step (1); (5) separating the groundwood pulp fiber suspension from step (2) into (a) an accepts fraction and (b) a rejects fraction, the latter comprising from about 30% up to about 85% by weight of the fiber suspension; (6) screening the rejects fraction 5 (b) of the groundwood pulp fiber suspension through a screen having screen openings of less than about 5 mm; (7) separating the fiber suspension from step (6) into (a) an accepts fraction and (b) a rejects fraction; (8) recycling the rejects fraction 7(b) to the defibrating step (3) and then to the groundwood pulp fiber suspension from the grinding step (1); (9) screening the accepts fraction 7(a) to form (a) a short-fiber accepts fraction of which from about 15 to about 60% comprises fibers passing through a sieve No. 150 in a Bauer-McNett classifier; and (b) a long-fiber rejects fraction of which at least 80% comprises long fibers retained on a sieve No. 150 in a Bauer-McNett classifier; (10) withdrawing the long-fiber rejects fraction 9 (b) as groundwood pulp product (ii); (11) blending the short-fiber accepts fraction 9 (a) with accepts fraction 5 (a); and (12) withdrawing the resulting blend as short-fiber accepts fraction groundwood pulp product (i).
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