Migration And Transformation Of Sulphate In Acid Mine Drainage And Its Effect On Heavy Metals

The exploitation of mineral resources in the process of providing people with the necessary resources for social development also produces a lot of pollutants,causing serious environmental problems.Especially in Acid mine drainage?Acid mine drainage,AMD?emissions more and more serious.Acid mine wastewater has very low pH,high concentration of SO₄^2-,Fe²⁺and rich in various heavy metals?such As Cd,Pb,As,Cu,Zn,Ni?.It is very important to study the cause of environmental impact and the law of change of coal mining.High concentration of sulfate wastewater discharged into the aquatic environment will produce a series of pollution and environmental effects,such as accelerated basins carbonate rock erosion,corrosion lead to building materials,can even change the original ecological regulating function of the water,and harm to human health.This study choose Zhijin county Guizhou province beads Tibetan town,acid mine drainage clusters as the research object,in season?January 2017?and the plentiful?August 2017?,the water and sediment sulfur forms,Fe and other heavy metal distribution characteristics were analyzed,explore the sulfate under the background of karst geology acid the transition and transform characteristics of coal mine drainage.The main results are as follows:?1?The pH of the river segment is basically stable at about 3,and slowly decreases with the flow direction;The higher EC value indicates the higher ion content in water.The ORP value of water is high,and it is increasing gradually.The increase of precipitation in the wet period has great influence on the concentration of Ca;The carbonate bedrock is continuously dissolved in the acid mine drainage along the stream during the dry water period,and the Ca concentration in the water body is increased.?2?The SO₄^2-content of water is very high in the study area,and the maximum is3886 mg/L in dry period,and the maximum is 3630 mg/L wet in period.There is a decrease in the flow direction,there is a certain degree of self-purification.The dissolved sulfur in the basin is mainly in the form of SO₄^2-,and the content of metastable sulfur is very low in this high oxidation state of AMD.ExS is a major form of sulfur in the sediments,and its content accounted for about 65%of the total sulfur?TS?,and the reduced sulfur content is relatively small,its content size order is ES<AVS<CRS.?3?The average concentration of heavy metals in water dissolved in the study area was Fe>Mn>Zn>Cu>Cr,with a high Fe content,and the mean value of the dry period and the wet period was 173.38 mg/L and 127.68 mg/L respectively.The heavy metal gradually decreases along the basin after the coal gangue yard point,and is consistent with the attenuation of SO₄^2-.?4?The change of small watershed in the study area is not significant to Fe in sediment.The average content of Fe was as high as 395.4 mg/kg and 408.17 mg/kg respectively in the water and dry periods.The amount of heavy metals in the sediments near the gangue dump is increased,which indicates that the gangue dump has significant influence on the environment.?5?The mass production of sediment in the gully is significantly correlated with SO₄^2-reduction.An important attenuation of Fe???under acidic conditions?pH 2.7³.3?is with SO₄^2-formation of iron-bearing minerals.?6?Obvious trait of sediment containing sulfur containing iron,XRD analysis,according to the main ingredients of montmorillonite,gypsum,quartz,calcite,etc.,hydroxyl and detect the amount of iron oxides and iron hydroxyl sulfate minerals,including iron ore,goethite,molisch's mineral water,etc.