Thermal Desorption Characteristics of Mercury Contaminated Tailings from Gold-Silver Mine

This study conducted thermal desorption experiments for the remediation of mercury-contaminated soils with a mercury concentration of 26.39 mg-Hg/kg from gold–silver mine tailings. The thermal desorption experiments were performed in a muffle furnace at a pressure of 1 atm in the temperature range from 300 to 700 C. In addition, indirect thermal treatment^o experiments were conducted by adding 20 g of homogeneous samples into the crucible for 1 to 30 min. The mercury concentrations of the residual samples were analyzed using EPA method 7471a. Based on the results of the analysis of mercury concentration in the thermal treatment, the thermal desorption characteristics of mercury contaminated tailings were analyzed using reaction rate theory. The reaction rate constants (k) were calculated from 1.3 × 10 to 1.9 × 10^-3-2 sec with a change in the temperature conditions. The results revealed that k increased with increasing temperature. In^-1 addition, the calculated pre-exponential factor and activation energy were 0.118 sec and 2.76 kcal/gmol, respectively.^-1 Furthermore, the thermal treatment conditions required to achieve the 4 mg-Hg/kg criteria for Hg content were approximately 1,451 s at 300 C and 992 s at 400 C.^oo.