Effect of Na2CO3 on production of NaHCO3 using desulfurized Na2SO4 waste

Abstract

Abstract 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 while minimizing the consumption of expensive NH3.