Preliminary Study on the Inhibition of Biological Oxidation in Reactive Mine Tailings by Agricultural Residues

摘要

The decomposition of multi-metal mine tailings pose significant risk to the environment as point sourees of acidic,metal-rich effluents (acid mine drainage [AMD]).The accelerated oxidative dissolution of sulfide minerals in tailings by acidophilic baeterias represented by Acidithiobacillusferrooxidans has been widely reported.The different agricultural residues added into the mediums of Acidithiobacillus ferrooxidans were investigated to study the impact of the acid-generating and Fe2+ oxidation.Six treatments for inhibiting the activity of Acidithiobacillus ferrooxidans were set up with four different agricultural residues.The changes in physicochemical parameters for up to 1 week were analyzed everyday.Differences of treatments were apparent among mediums that added the powder of walnut shell and those that added other three agricultural residues or nothing.These differences included higher pH values,lower redox potentials,and higher concentrations of soluble Fe2+ in the medium added powder of walnut shell.The lab experiment showed that the powder of walnut shell was effective in inhibiting the activity of Acidithiobacillus ferrooxidans The inhibition rote of Fe2+ oxidation measured at the seventh day was 58.41％ with adding powder of walnut shell at the concentration of 2g/L.The results suggested that continuous input of walnut shell could control pollution and promote re-vegetation of the area covered by coal mine wastes.