PURPOSE: To provide the method for removing from a caught ash the sodium and potassium salts which are concentrated and accumulated in a pulp-digesting chemical as impurities.
CONSTITUTION: The method for removing sodium and potassium salts from the caught ash of the soda-recovering boiler comprises slurrying the ash caught from the combustion exhaust gas of the soda-recovering boiler in water, controlling the pH of the slurry to ≤10 by the addition of sulfuric acid, controlling the temperature of the slurry to ≥20°C, holding the mixture for a definite time to dissolve the sodium and potassium salts contained in the caught ash in water, cooling the slurry at <20°C, separating and recovering the deposited solid contents from the liquid portion, and throwing away the left liquid portion outside the system.
TATEISHI MASAKAZU
YAGI MICHIMASA
MAEDA TAKAYUKI
ARAKAWA YOSHIHISA
