foerfarande foer treatment and aatervinning of blekeriavlopp fraan massafabriker

摘要

The invention relates to a method for treatment and recycling of pulp mill bleach plant effluents. Chlorinecontaining chemicals are separated from the fluid obtained from the first bleach stage (DC) implemented with these chlorine-containing bleach chemicals on pulp (2) that has been washed (W) and partially dewatered (P1) whereby the pulp (3) from the mentioned bleach stage (DC), with chlorine-containing bleach chemicals, is dewatered (P2) up to about the same dryness of at least 25 % and at most 35 % as for the mentioned thereto incoming pulp (2) and whereby the fluid from the second dewatering (P2) is recycled to the bleach stage (DC) and the outcoming fluid (9) from the bleach stage (DC) is evaporated (EV) through indirect heating with condensing vapour obtained through recompression of vapour stripped in the evaporation. The dewatering (P1, P2) is preferably performed by pressing out the liquid from the pulp (2, 3) and the evaporation (EV) in several stages connected in parallel or in series at a temperature below 70.degree.C.