Effects of partial borate aytocausticizing on kraft recovery operations

Copyright Pulp & Paper Canada. Reprinted with permission from Annex Business Media.Trials on partial borate autocausticizing conducted at several kraft pulp mills showed that lime consumption was lowered and there were no effects of borate on pulp quality, effluent quality, chemical recovery process equipment, and digester and lime kiln operations. Several problems were experienced during operation of evaporators, recaust plants and recovery boilers, but most have been overcome. Results of laboratory studies suggest that the efficiency of the borate autocausticizing reaction that occurs in recovery boilers increases as the boron concentration in the liquor decreases. Since the autocausticizing reaction requires heat, the technology may be beneficial for boilers that are thermally limited. For boilers that have a low heat input, it will be difficult to achieve a high reaction efficiencyThis work was supported by us Borax Inc. and Natural Sciences and Engineering Research Council of Canada