Effects of Chloride, Potassium, and Sulfate on the Causticizing Reaction in the Kraft Recovery Process

Abstract

We studied the effects of chloride (Cl), potassium (K), and sulfate (SO4) on the equilibrium of the causticizing reaction over a wide range of causticizing conditions, using OLI, an advanced thermodynamic program for equilibrium calculations in aqueous solutions of ionic salts. Cl, K, and SO4 were shown to have little or no effect on the causticizing equilibrium. Under a given causticizing condition, coastal mills, due to their much higher NaCl concentration, are predicted to have a causticizing efficiency 1%–2% lower than that of inland mills.