The Research On Electro-Remediation Technology Of Mine Tailings

There are many heavy metals in the mine tailings. Most of the tailings have been left without any management. It has become the main source of heavy metal contamination in the mining areas, which including soil substrates contaminated, soil texture destroyed, short of nutrient, ecological landscape destroyed, water pollution and biological diversity decrease。Work should do to restore the ecology on mined areas. Basing on the research ago, The elecrokinetic technique for removing heavy metals in a Lead-Zinc mine tailing was examined. The redistributions of Pb, Zn and Cu were determined using the sequential extraction procedure of the optimized European Community Burean of Reference (BCR) before and after the examination.Electroremediation technique is an advancing task of global environment science and technology. Its principle is that: application of direct electric current via electrodes immersed in a saturated soil results in oxidation at the anode, generating an acid front that cause desorption and dissolution of heavy metals. The desorped and soluted heavy metals are migrated toward cathode reservoir by electric field and ions concentration grads by the means of electromigration, electroosmosis and diffusing.Firstly, a series of elecrokinetic technique tests about mine tailings are conducted. The results showed that total removal efficiencies of Pb, Zn and Cu were 26.5%, 24.4% and 30.7% respectively after electroremediation for seven days. The removal efficiencies of acid extraction fraction of Pb, Zn and Cu were 47.8%, 73.4% and 71.3%.The removal efficiencies of Fe and Mn oxides fraction of Pb and Cu were 30.1% and 35.1%. The removal efficiencies of other fractions were only about 8%. The electroremediation technology is efficient to remedy the Lead-Zinc mine tailing. pH value of the soil decreased electro-conductivity of soil, and then reduce remediation efficiency by precipitating of heavy metals. Hence, electroremediation techniques should be enhanced so as to efficiently remove Pb from contaminated red soil.Secondly, a series of experiments used enhancement elecrokinetic technique are conducted. Experiment II is conducted by the middle recycle washing technology. The results showed that total removal efficiencies of Pb, Zn and Cu was 40.8%,36.9%and45.1% respectively after electroremediation for seven days. Contrasted to experiment I, the removal efficiencies was increased by 14.3 %,12.5%and 14.4%respectively. The removal efficiencies of acid extraction fraction of Pb, Zn and Cu were 62.4% ,84.8 % and 80.8 % . Contrasted to experiment I, the removal efficiencies was increased by 14.6%,11.1%and 9.5%. The removal efficiencies of other fractions of the heavy metals are also increased.Experiment III is conducted by controlling pH value of the cathode reservoir with HAc. The results showed that total removal efficiencies of Pb, Zn and Cu was 39.3%,37.3%and 50% respectively after electroremediation for seven days. Contrasted to experiment I, the removal efficiencies was increased by 12.8%,12.9%and 19.3%respectively. The removal efficiencies of acid extraction fraction of Pb, Zn and Cu were69.8%,85.8%and 83.5%. Contrasted to experiment I, the removal efficiencies was increased by 22%,12.4%and 12.2%. The removal efficiencies of other fractions of the heavy metals are also increased.