Migration Patterns And Contamination Assessment Of Heavy Trace Metals Of Cd And Pb In Gannan Tungsten Ores District

Mineral is natural simple substance or compound of the action of chemical elements inthe Geological processes,the human survival depend on it. About95%of the energy and80%of industrial raw materials are directly or indirectly from the mineral resources in our country.Tungsten is the characteristic minerals of implement protective mining in government.Gannan tungsten mining made a great contribution for the national economic development.Produced a kind of solid waste--tailings in the process of ore dressing.Tailings containedgangue mineral and a certain number of metal sulfide minerals.The tailings stacked in theopen air and under the influence of precipitation seepage will release the migration of heavymetals in tailings,such as Cd, Pb, caused heavy metal pollution problem of surroundingenvironment.This paper used dynamic column leaching experiment simulationed tailings-water underthe action of the release of heavy metals Cd and Pb.Simulated liquid pH value of3,4,5,6,7and8conditions,drench filtrate pH average was6.24~6.92. And simulated liquid pH anddrench filtrate pH value is basically, and tailings of acid-base buffering capacity was stronger.Drench filtrate of Cd and Pb to release a quantity to a day related to simulate fluid pH valueare negatively, Pb leaching greater than Cd leaching amount every day.Heavy metals releasemigration rate is greater than the leaching strength into liquid, appeared the phenomenon ofearly shock wave and later gradually stables. Take the tail pillar leaching for35days,analyzedthe full amount for tail pillar tailings.In the depth of30cm profile,Cd and Pb appeared littleenrichment,is the depth of0cm for1~3and1~2times.Kinetic characteristics of tailingsreleasing indicates,Cd and Pb migration is controlled by sulphide oxidation and adsorptionmechanism.Tailings surrounding soil mainly including hills, paddy soil and vegetable plantationsoil,The harm to human beings mainly comes from the paddy soil and vegetable plantationsoil pollution.Mining area surrounding farmland soil heavy metal geochemical studyshowsthat:Cd and Pb pollution of heavy metals in soil scope is bigger,the pollution level:Cd>>Pb.Cd and Pb element content in Paddy soil and vegetable plantation appeared a moderate andmore pollution,should be taken some prevention and control measures.Organisms in the soilavailable state (water soluble and exchangeable states) of1.2~5.3%in the total soil Cd,creatures cannot use (residue) of20.0~40.1%,several other states total of58.0~78.0%;Thebioavailable of Pb is2.4~6.5%,Creatures cannot use state accounts for only6.1~39.1%,several other states total of56.7~87.4%.Although bioavailable content is low,but still exist alot of potential pollution.