New Process for Na₂CO₃ Production from Na₂SO₄ Based on Modeling the Na₂SO₄–(NH₄)₂SO₄–MEA–MEG–H₂O System

Abstract

Alternative means for soda ash (Na 2 CO 3 ) production from sodium sulfate (Na 2 SO 4 ) are needed due to the intensive consumption of energy in the conventional Mirabilite-Solvay process (MSP). We demonstrate a new process to produce soda ash using sodium sulfate as a feed material. The new process relies on the antisolvent crystallization of unreacted Na 2 SO 4 to separate it from soluble (NH 4 ) 2 SO 4 in a mixed monoethanolamine (MEA) and monoethylene glycol (MEG) solution. To develop the process, the solubilities of Na 2 SO 4 and (NH 4 ) 2 SO 4 solids in aqueous mixed MEA−MEG solutions were first measured and then modeled using regressed paired-ion interactions from the electrolyte nonrandom two-liquid (E-NRTL) model. Anhydrous dense soda ash with a bulk density of up to 1146 kg/m 3 was obtained when the concentrated Na 2 SO 4 brines reacted with CO 2 and NH 3 .(2)