Vertical Distribution of Cyanide and Heavy Metals in a Tailings Pond in Jilin, China

Abstract

After long-term accumulation, weathering and rainfall of metals and non-metals in tailings ponds, the chemical composition will change, and the surface heavy metals may gradually migrate to the bottom layer, thus showing a cumulative effect. At present, the distribution of cyanide and heavy metals in vertical space has not been reported. In this work, 12 sampling points were arranged for a cyanide tailings pond by the grid method in Jilin, China. The contents of cyanide and heavy metals were determined according to the standard method. The results show that the heavy metals in the tailings were mainly Cu, Pb, Zn and Mn (342.83 mg/kg, 571.09 mg/kg, 610.15 mg/kg and 796.63 mg/kg, respectively), and the concentration of heavy metals in the horizontal direction does not change significantly. It should be noted that the concentrations of zinc and manganese did not change much in the vertical direction. The concentration of copper and lead increased with the increase in depth. The concentration of cyanide at the sampling site far away from human activities was higher at 6.71 mg/kg, and the average concentration is 2.5 mg/kg. In addition, because the cyanide is unstable and affected by factors such as light and rainfall, the concentration change in the vertical direction fluctuates.

Socio-Environmental Risks Linked with Mine Tailings Chemical Composition: Promoting Responsible and Safe Mine Tailings Management Considering Copper and Gold Mining Experiences from Chile and Peru

“…Decreases in process performance may occur if the pH fluctuates outside of this optimum range. The optimum pH must be developed experimentally, as the maximum removals of cyanide and metals occur at different pH values [ 48 , 63 , 66 ].…”