Utilization of Waste Bittern as a Source for Magnesium Production and an Absorbent for Capturing Carbon Dioxide = Utilization of Waste Bittern as a Source for Magnesium Production and an Absorbent for Capturing Carbon Dioxide

다국어 초록 (Multilingual Abstract)

This study examined the suitability of waste bittern, from slattern, as a source for magnesium (Mg) production and an absorbent for CO₂. A sequential two-step process was investigated; i) Mg was recovered by adding NaOH and precipitating as Mg(OH)₂, and ii) CO₂ was captured using the ammonia-soda process where ammoniated residual bittern reacted with CO₂. At NaOH:Mg molar ratios of 2.70:1 to 2.75:1 and pH 9.5-10, >99% of Mg ions (Mg ²⁺) precipitated from the bittern. Precipitate recovery was 100-120 g/L of the bittern and contained 94% Mg(OH)₂ after washing with water. The NaOH concentration did not significantly influence Mg²⁺ precipitation efficiency; however, it did affect the Na+ concentration in the precipitate filtrate considerably. The precipitate filtrate containing a large amount of Na+ was able to capture CO ₂ effectively with an ammonia catalyst (NH4OH≥3%), forming NaHCO₃. Higher Na⁺ concentrations resulted in higher absorption of CO₂, because NaHCO₃ solubility influences CO₂ capture in the ammonia-soda process. The optimum amount of NH4OH about 5%, at whichNaHCO₃ precipitate (97% purity) recovery was 120 g/L, which is equivalent to CO₂ capture of 63 g/L. The results show that bittern may be a suitable resource for Mg production and CO₂ capture.