Process for recausticizing green liquor

US10011948B2 · kind B2 · utility

Assignee

• MONDI AG · AT

Inventors

• Walter Ruef · Wolfsberg, AT
• Manfred Hacker · Senden, DE
• Stefan Raffalt · St. Gertraud, AT

Key dates

• Filing date: Feb 18, 2014
• Grant date: Jul 3, 2018
• Expiry date: Feb 18, 2034

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P40/40
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A process for recausticizing green liquor in a sulphate or Kraft process for wood pulp production, in which a green liquor consisting of an aqueous solution of sodium carbonate as the major component and sodium sulphide is admixed with calcium oxide in a slaker and undergoes a reaction in a recausticizer to form an aqueous suspension containing sodium hydroxide and calcium carbonate as the major components, which suspension is filtered on a first filter and subsequently, after dilution with water in a dilution vessel, is fed over further filters two or three times and filtered to separate solids suspended therein, characterized in that after a first separation of calcium carbonate as the major component and calcium oxide as the minor component, carbon dioxide is added to the aqueous suspension at least during dilution in a dilution vessel and in particular in the dilution vessel (s) upstream of a second and/or a third filter.