Study Of Heavy Metal Geochemistry Behavior During The Oxidation In The Huanglongpu Mo Mine Tailings

Tailings is one of the waste which released by mining. It's not only devoures a great of land, but also releases a lot of heavy mentals and AMD which caused environmental pollution by weathering and oxidation in the surface conditions weathering.The thesis studied geochemical behaviour of the heavy metal elements during weatherin- g in tailings site 1 of huanglongpu, by using heavy metal content analysis, the seven-step extraction technique developed by Dold, leaching simulation experiment, and analyses of mineral composition and chemical speciation. The main conclusions which the paper obtained are as follows:(1)In addition to the contents of Cu and Pb are higher than the second class of National Soil Quality Standard values, and the content of Cd exceeds the first class of Standard values, the other heavy metals of this tailings reservoir did not overweight the standard values. The distribution regulation of heavy metals in this tailings reservoir is the enrich in middle and deficient around in the shallow surface around the tailings, but the content of Cu,Fe in middle is lower than that around for relatively easy to transfer and erosion.(2)Chemical fractions analysis showed that the chemical forms of heavy metals are different, generally, the domainant status were in T6 sulfide fraction and T7 residual fraction. The results indicated that the mobilities of Cu,Zn,Fe are stronger than the others.So the damage was not so serious.(3)Through the leaching simulation experiment of tailings with different containing of pyrite we can understand:Higher content of pyrite, smaller leachate pH value.The concentration of Copper, lead, chromium is positively correlated with content of pyrite, cadmium's dissolution has littlerelations with pyrite content.Therefore, Zinc's dissolution in oxidized zone has negatively relations, and in underlying oxidized zone it has positively relations.This may be related with zinc metal activity.It's suggest that the relationship of the total ions concentration of leaching dissolutions and leaching time, the total ions concentration increases unceasingly with the constantly extend leaching time. In this experimental period, it has linear relationship with leaching time. It explans that the sulfide ore tailings is the important sources of heavy metal ions to the surroundings.The accumulating amount of Cu,Pb,Cr release is basically positively correlated with the content of pyrite, and the Zn,Cd's release accumulating amount had no obvious relationship with the content of pyrite. Then, the iron's has negative correlation with pyrite.In order to reduce tailings pollution and repair the mine environment, people put forward different kinds of tailings coverage schemes. This paper studies indicate that the schemes can not effectively block migration of the heavy metal element.