Study on the Law of Release of Heavy Metal from Waste Rock of Dexing Copper Mine

摘要

Release law of heavy metals from waste rock are significant to the heavy metal pollution control in nonferrous metal mining-area. We took the waste rock of Dexing Copper mine as the object and carried out the leaching experiment with simulated acid rain(pH3.0, pH 4.0, pH6.0 and pH8.0) which were conducted to investigate the release law of heavy metals(Cu, Pb, Zn, Cd and As) from waste rock. The results of the experiments were as follows: Waste rocks have relatively acid producing capacity in natural rainfall; with the increase of pH value of added liquid, the electric conductivity reduces gradually, and the amount of heavy metal release reduces. The release process of 5 heavy metal elements (Cu, Pb, Zn, Cd and As) from the waste rocks can be classified into two stages, i.e. rapid release stage and slow release stage. They are the mostly easily to be released and migrated under the action of strong acid with the lowest pH, and the leaching quantity is relatively low if leached by leachate with pH nearly neutral.