A process for concentrating a black liquor.

摘要

A process and an apparatus are disclosed for concentrating an alkaline waste liquor which is discharged from a step of alkaline cooking wood fiber in order to recover cooking chemicals, characterized in that CO2 gas and/or gas containing CO2 gas is added to said waste liquor as a viscosity lowering agent, as a boiling point lowering agent and/or as a solidification promoter before and/or during said concentration.