Andritz Oy

Metso Power Oy

Ismo Reilama

Keijo Salmenoja

Janne Vehmaa

Risto Hämäläinen

Kari Kovasin

Marjukka Joutsimo

Niko Metsämuuronen

A method of treating fly ash containing sodium sulfate from a recovery boiler of a chemical pulp mill. This method includes at least the following steps: a) ash is dissolved in an aqueous solution and the pH of the solution is adjusted with alkali for precipitating impurities, b) the solution is filtered for removing the impurities containing precipitate, c) sodium sulfate is crystallized from the solution and the crystals are separated from the solution by filtering or by centrifugation, and d) the crystallized sodium sulfate is used as initial material for producing sodium and sulfur containing chemicals or as process chemical.

Method of treating fly ash of a recovery boiler

A method of producing chemical pulp including at least the following steps: a) wood chips or other comminuted ligno-cellulosic fibrous material is treated with a polysulfide-containing cooking liquor in an impregnation stage at a temperature of 90-145&#xb0; C., and b) slurry of fibrous material from step a) is heated into cooking temperature and cooked for producing pulp having a desired kappa number. After step a) mercaptide ions are added into the slurry of fibrous material and the fibrous material is treated at cooking temperature in step b).

Method of producing chemical pulp

In a method for processing flue gases, flue gases from an incineration plant for non-condensable gases of a kraft pulp mill are scrubbed by means of a calcium compound. The calcium compound is lime mud taken from the chemical recirculation of the kraft pulp mill after causticization and before a lime reburning kiln, and it is used in the scrubbing of gas as a substance reacting with sulphur dioxide.

Method for processing flue gases

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Reila, Finland

Ismo Reilama