Study on As and Mn Release Characteristics of a Tin-Tailing Pond under Simulated Condition of Acid Rain
In attempting to study As and Mn release from the wastewater of a tin-tailing pond in Gejiu City of Yunnan Prov-ince on the condition that the tin tailing have undergone rainfall leaching and long-term soaking,a static immersion and dynamic leaching experiment was conducted focusing on the changes of tailing mineral and micro-morphology.Conse-quently,the experiment revealed that rainfall leaching and long-term soaking would cause the significant release of As and Mn,and with a decrease of the solid-liquid ratio,the concentrations of As and Mn in the soaking solution tended to de-cline;a high solid-liquid ratio would extend the release cycle of As,but to Mn that was on the contrary.Since the constituent of alkaline minerals was rather high,the capacity of acid-neutrization appeared strong,the effect of initial pH value of sim-ulated rainfall leaching water or soaking water on the release of As and Mn was small.In regard to the model fitting of heavy-metal release,it was showed that the release of As in tin tailing fit the second-order kinetic equation,while Mn release fit the second-order kinetic equation and two-rate equation.