Kleppe, Peder J.; Minja, Rwaichi J. A.
Description:
Developments in polysulphide pulping during the last 35
years are reviewed with emphasis on the successful PSpulping
experience at the Peterson kraft mill in Moss,
Norway. New and economical PS generation technology not
disturbing the Na/S-balance in kraft mills will enhance
application of PS-pulping world wide. Multi-stage PSpulping
may improve the yield increase for a given PSsulphur
charge to a digester system. Especially PS-black
liquor impregnation followed by kraft cooking with
conventional white liquor is interesting.
Drying of fresh wood chips before PS-AQ pulping has a
negative effect on obtainable yield increase.
The paper and board making properties of polysulphide-AQ
pulps are comparable to kraft pulps from a given wood
source. PS-AQ paper grade pulps seem to preserve their
paper making properties by recycling better than kraft pulps
containing less hemicelluloses.