| The mining and smelting of metal mines may cause environmental pollution.In this study,Zuoxiguo Antimony Mine in Kaiyuan city,Yunnan Province and Dachang Antimony Mine in Qinglong,Guizhou Province are selected as the research areas.Based on the investigation of regional pollution status,the release characteristics of heavy metals in the tailings of two antimony mining areas were systematically analyzed,and the pollution risk of the mining area to the regional environment was also studied.Through chemical stabilization test,the heavy metals in antimony tailings were stabilized and analyzed.Through orthogonal test,the best scheme of mass ratio of stabilizer to sample and curing period was determined,the following main conclusions have been drawn:(1)The tailings of Zuoxiguo Antimony Mine are acidic,while those of Dachang Antimony Mine are neutral.The highest contents of heavy metals Sb,As,Cr,Cu,Zn,Cdand Pb in the tailings of Zuoxiguo Antimony Mine are 71166.91,590.69,431.19,450.77,130.88,2.528 and555.25mg / kg,respectively.The highest contents of heavy metals Sb,As,Cr,Cu,Zn,Cdand Pb in the tailings of Dachang Antimony Mine are 7603.70,911.06,252.03,90.21,136.17,1.17 and376.28mg / kg,respectively.The leaching toxicity test shows that the tailings from the two antimony mining areas do not belong to the category of hazardous waste,however,as the average value of Zuoxiguo tailings is 3.88(pH < 6),it belongs to class II general industrial solid waste according to GB 18599-2001.(2)The static release experiment of heavy metals in tailings of two antimony mines shows that pH value has obvious control effect on the release of heavy metals.Among the four pH(pH =2.98,5.10,7.00,9.77)extractants,Sb,Cu and Zn from Zuoxiguo were more easily released under acidic conditions(pH = 2.98),As,Cr,Cd and Pb were more easily released under weak acidic conditions(pH = 5.10);Sb,As,Cu and Cr from Dachang were more easily released from minerals under acidic conditions(pH = 2.98),while Zn and Pb were more easily released under acidic conditions(pH = 2.98)and alkaline conditions(pH = 9.77)is easier to release from minerals.On the whole,acidic conditions are favorable for the release of heavy metals in tailings pond.(3)The geoaccumulation index method was used to evaluate the heavy metal pollution in the tailings of antimony mine.The results showed that Sb in the tailings of two antimony mines was extremely polluted.As,Cd and Pb were between moderate pollution and severe pollution,Cu and Cr were from non pollution to moderate pollution,and Zn was not polluted.The potential ecological risk index method is used to evaluate the risk of surface tailings in antimony mining area.The results show that the ecological risk of Sb in the two mining areas is the largest,followed by As,which is between medium risk and very high risk,while Cr,Cu,Zn,Cd and Pb have no risk.(4)The stabilization test of Sb,As and Pb in tailings was carried out by using the composite stabilizer of fly ash,zeolite powder and quicklime.The results show that the application of fly ash and zeolite powder has a significant stabilizing effect on the release of heavy metals in tailings,while the addition of quicklime has no obvious effect on improving the stabilization efficiency.Among them,15%(w/w)fly ash and 15%(w/w)zeolite powder were added to the test samples,and the curing time was 28 days.The stabilization effect of Sb,As and Pb was significant. |
