Method for the production of green liquor

摘要

The method is for production of green liquor in association with a causticizing process during recovery of chemicals in manufacture of sulphate pulp. A smelt ( 14 ) of chemicals principally consisting of Na₂S and Na₂CO₃ from a soda boiler ( 1 ) is provided. Weak liquor ( 15 ) that contains dissolved NaOH and CaO is provided. A dissolving tank ( 2 ) is provided in which the smelt ( 14 ) from the soda boiler ( 1 ) is dissolved in the weak liquor ( 15 ) in order to form green liquor ( 16 ). A solution of NaOH is added to the weak liquor ( 15 ), at a position before the weak liquor ( 15 ) is added to the dissolving tank, in order to increase the concentration of NaOH in the weak liquor ( 15 ) such that a fraction of CaO that is presently dissolved in the weak liquor ( 15 ) precipitates.