Effect of Na₂CO₃ on Production of NaHCO₃ Using Desulfurized Na₂SO₄ Waste

CO₂ is the primary greenhouse gas emitted through human activities which cause global warming. Many countries and international regulations aim to reduce CO₂ and encourage development of a net-zero society by 2050, thus, CCUS (carbon capture, utilization, and storage) can be considered as a key technology for achieving this goal. Among the many industrial processes, NaHCO₃ production is a representative CCUS technology which satisfies both CO₂ reduction and economic incentive. Recently, Na₂SO₄ waste, containing 15% impurities (i.e., various heavy metals), produced as a by-product generated from desulfurized processes in steel industry has received a great deal of attention since landfilling has been the only way to treat it. Na₂SO₄ could be a suitable source of NaHCO₃ production as CCUS; however, there are no commercial processes for production of NaHCO₃ using Na₂SO₄ as the raw material, since it has low production efficiency compared to other Na⁺ sources. This study evaluates the regeneration of NaHCO₃ using Na₂SO₄ waste and our results show that a combination of Na₂SO₄ waste and the addition of 20% Na₂CO₃ can sharply increase the yield of NaHCO₃ with minimizing the consumption of expensive NH₃ since alkaline properties of Na₂CO₃.