Alkaline peroxide mechanical pulping of non-woody species
AssigneeAlberta Research Council
InventorGeorge X. Pan
Life of this patent
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Abstract
High-yield chemimechanical lignocellulosic pulp is produced from non-woody species by cutting and screening the non-woody species, soaking them in an acidic aqueous solution preferably containing a chelating agent, treating the washed non-woody species with an alkaline peroxide solution containing a second chelating agent, and mechanical refining. To further increase the bleaching efficiency the non-woody species are impregnated with ozone or peracetic acid. The resulting pulp has a relatively high brightness while the consumption of peroxide is reduced compared to prior art processes.
Claims21
A process for preparing lignocellulosic pulp from non-woody species, the process comprising the step of:
- (a) impregnating the non-woody species with an alkaline peroxide solution at a temperature and for a time effective to bleach the non-woody species, and (b) mechanically defibrating the impregnated non-woody species to produce pulp, wherein prior to step (a), pretreating the non-woody species with an aqueous acidic solution at a pH from about 2 to about 3, at a temperature and for a time effective to enhance peroxide bleaching efficiency in step (a).
Dependencies are inferred from the claim text.