Kinetics of Ba(OH)₂ Reaction with Na₂CO₃ and Na₂SO₄ & Particle Separation Characteristics from White Liquor

Abstract

The purpose of this study is to determining the feasibility of replacing causticizing (calcium based reactions and precipitate) with bausticizing (barium based reactions and precipitates). Bausticizing is not limited by chemical equilibrium and thus can proceed to full conversion eliminating the dead load of inert sodium carbonate in the white liquor. The comparison is centered on the kinetics and conversion as well as precipitate sedimentation.

BaCO₃ and BaSO₄ approach full conversion (97.7% and 95.9% respectively) after a 5 to 10 second reaction at room temperature with 0.1M feed solutions (Ba(OH)₂, Na2CO₃, and Na2SO₄). Barium mud settling behavior is comparable to that of lime mud and can possibly be carried out by existing sedimentation tanks within a pulp mill.