The Release And Speciation On Arsenic Of Different Types Of Gold Mine Tailings In Liaoning Dandong

In natural environment, Arsenic exists mainly in the inorganic and organic metalarsenic forms and mainly exists as As3-, As0, As3+and As5+. During the process ofexploitation of mineral resources, Arsenic will be activated into various forms andreleased into the environment, causing pollution to the water body, atmosphere, soiletc..In this paper, we choose two different types of gold mine tailings as the researchobject to analyze the physicochemical characteristics of the samplings which wecollect in two gold mine tailings. By using Tessier leaching test and batch test, We tryto find out the mechanism of release of Arsenic in different situation such as differentsoak period, different pH, different Ionic strength, different content of the phosphate.The main research harvests are as follows:The oxidation-reduction potential of the flotation tailings (N1series) and thebiological oxidation tailings (N2series) are approximately at about300mV, the pHis about8.5and the pHpzcis8.5.about The main minerals are quartz, dolomite andclay minerals and the main components are Si and Al in the flotation tailings. TheArsenic of the flotation tailings is mainly in FeAsS form. However, the mainminerals are gypsum and the main components are Fe, Ca and S. The Arsenic of thebiological oxidation tailings is mainly in FeAsS and As2O5form.The percent content of the residual speciation of Arsenic is more than80%inthis six samples. Under natural conditions, the residual speciation of Arsenic is hardto be released which is considered as stable state.The results of the batch test show that the release concentration of Arsenic ofthe biological oxidation tailing sample (N2-2) is much higher than the flotationtailing sample (N1-1). The release concentration of Arsenic of the flotation tailingsample (N1-1) reaches balance faster than the biological oxidation tailing sample(N2-2). The release concentration of Arsenic of the flotation tailing sample is at206ug/L. The effect of variable pH on the release concentration of Arsenic of theflotation tailing sample is significant. The increase of ionic strength will lead to the more dissolution of Arsenic. The content of phosphate will affect the releaseconcentration of Arsenic.