Magnesite and brucite are found in magnesium carbonate and hydroxide minerals in nature. In this study, removal efficiency of high concentration heavy metal in acidic wastewater with calcination temperature of magnesite and brucite was evaluated. The samples were used fired magnesite and brucite at 600, 800, and 1000^oC for 1 hour. XRD analysis was performed to study mineralogical properties of magnesite and brucite and material produced after calcination. The concentration after reaction with acidic wastewater of high concentration heavy metal was analyzed using ICP. In the heavy metal removal experiment, 3g of powder samples was added to 250ml of wastewater and stirred at 300 rpm for 2 minutes, and the supernatant was collected after 1 hour, 12 hours, and 24 hours, respectively, and filtered with a 0.45um membrane filter, and then ICP analysis was performed. According to the XRD analysis results, when magnesite(MgCO₃) and brucite[Mg(OH)₂] are fired, both change to MgO regardless of calcination temperature and time. Raw wastewater that are pH 3.68, Cd 182.74 mg/L, Cu 31.11 mg/L, Fe 1.03 mg/L, Mn 1458.43 mg/L, Zn 11979.85 mg/L is extremely acidic and contains a very high concentration of heavy metals. The samples with the highest removal efficiency of heavy metals were MgCO₂ fired at 600^oC and reacted for 24 hours, and results are Cd 47.1%, Cu 99.8%, Fe 99.9%, Mn 33.7%, and Zn 67.0%. The efficiency of Mg(OH)₂ fired at 600^oC and reacted for 24 hours are 47.1% of Cd, 99.8% of Cu, 99.9% of Fe, 33.7% of Mn, and 67.0% of Zn. The removal efficiency of fired MgCO₃ and Mg(OH)₂ is 96.6-99.8% and 99.9-100% for Cu and Fe, respectively, and Cd 9.3-47.1%, Mn 5.4-33.7%, and Zn 15.6-67.0%.

Jae Min Kim

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