Mechanism Of Heavy Metals Release From Tailings Of Typical Antimony Mine In Karst Area

China has the largest reserves and production of antimony in the world,and most of antimony ore distributed in the south west,with a long history of antimony exploration.Guizhou and Yunnan are typically karst landscapes with fragile ecological environment.Therefore,it is of great importance to study the migration and distribution characteristics of heavy metals in the natural storage process of different antimony mine tailings,the internal and external factors influence the process of heavy metal releasing,and exploring the coupling relationship of antimony releasing,iron and sulphur,which can provides theoretical data supporting for the management of heavy metal pollution in the antimony mine tailings ponds and of great practical significance for mine environmental improvement,prevention and prediction.In this paper,the tailing sample collecting from Qinglong and Banpo antimony mine in Guizhou,and an antimony mine in Kaiyuan of Yunnan.And a total of 88 samples were collected.The physical and chemical characteristics of the tailing samples,the distribution characteristic of heavy metals were analysed through the method of national standard analysis method,the correlation of each heavy metals and the coupling relationship between iron,sulphur and antimony were analysed through the effective data processing methods.The releasing characteristics,internal and external influsing factors of heavy metals during the process were analysed by laboratory simulation static leaching experiments.The main conclusions were obtained as followed:(1)Through analysis of physical and chemical properties of tailings and the heavy metal content in three typical antimony mines,the tailings in Qinglong and Kaiyuan antimony mine are more acidic,and the tailings of Banpo antimony mine are alkaline;Three typical antimony mine tailings are mainly polluted by antimony(Sb),arsenic(As)and cadmium(Cd).The antimony content in the tailings of an antimony mine in Kaiyuan City,Yunnan seriously exceeded the national standard background value.(2)Through simulated leaching experiments,the p H,conductivity,and morphological characteristics of the leaching solution before and after leaching during the tailings leaching process were analyzed with time.It was found that the p H of the three antimony ore leaching solutions tended to be neutral,and the conductivity increased with the leaching time,the surface morphology of the tailings becomes rough after leaching.The antimony releasing characteristics of the three typical antimony tailings are similar.The release characteristics of the same antimony ore tailings at different depths are same.The cumulative release of antimony and arsenic increases with tailings depth,but other heavy metals varies little with depth.(3)Through analysis of the bioavailability of arsenic and antimony in tailings,connection between iron,sulfur and heavy metal antimony.It is find that the sulfur and iron can promote the migration,transformation and releasing of antimony.And the releasing of antimony with time can be well fitted by the double constant rate equation and the simplified Elovich equation.