Regeneration of Sodium Bicarbonate from Industrial Desulfurization Waste

Abstract Description: In our efforts to enhance the recycling of industrial waste and achieve zero-waste technology, we have focused on optimizing the regeneration process of sodium bicarbonate from desulfurization waste by employing aqueous ammonia. Sodium bicarbonate plays a crucial role in the absorption of sulfur dioxide (SO2) gas during the flue gas desulfurization process. X-ray fluorescence analysis has revealed that the composition of desulfurization waste predominantly consists of 86.2% sodium sulfate. However, an initial challenge we encountered was the rapid formation of unwanted ammonium bicarbonate deposits within the reactor when ammonia gas was used, which hampered the reaction's efficiency and resulted in inadequate yields. In response, we conducted a detailed investigation into the impact of varying the dosage of ammonia solution to improve the overall process. Our findings indicate that the yield and purity of sodium bicarbonate regenerated from desulfurization waste are nearly comparable to those obtained from pure sodium sulfate, with yields/purity percentages of 58.2/85.9% and 56.6/91.5%, respectively. This result underscores the efficacy of our optimization efforts. Furthermore, we observed that the regenerated sodium bicarbonate, benefiting from a greater surface area, exhibits superior desulfurization performance compared to commercial sodium bicarbonate. Specifically, the as-regenerated sample achieved a 97% SO2 removal rate when tested on a 200 ppm SO2 gas stream at a feeding rate of 5 grams per minute, as opposed to an 88.6% removal rate by commercial sodium bicarbonate under the same conditions. In conclusion, these promising results highlight the potential of our optimized regeneration process to not only contribute to industrial waste recycling but also enhance the effectiveness of flue gas desulfurization techniques.

Keywords: Flue gas desulfurization process
Sodium bicarbonate
Na-based absorbents
Regeneration process
SOx removal
Desulfurization waste

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