Study On The Migration Law Of Heavy Metals In The Typical Tailings Pond In Tongling,Anhui

Tongling is rich in mineral resources.During many years of mining activities,a large amount of tailings have been produced and accumulated in nearby tailings ponds,which has an impact on the surrounding environment.It is of great significance to explore the law of heavy metal migration for the reclamation and treatment of tailings pond.Under the condition of natural rainfall,the tailing pond is generally subjected to the dynamic leaching of rainwater.In order to get closer to the actual situation,the research on the release law of heavy metals in tailings ponds at home and abroad is mainly carried out by dynamic leaching experiments,which mainly studies the release and migration law of heavy metals under different occurrence forms,different acidity and different leaching time,while more scholars pay attention to the release law of heavy metals under different pH conditions and the results show that the stronger the acidity,the more conducive to the elution of heavy metal ions in the tailings.This study takes the Dongguashan mining area,Fenghuangshan mining area and Xinqiao mining area as the research area,and takes the typical tailings pond and surrounding soil in the mining area as the research objects.The main contents are to determine the composition and occurrence of the main heavy metals in the tailings pond and surrounding soil;To study the release law of heavy metals in the tailing samples over time and the characteristics of dissolution and migration in the vertical direction through the laboratory leaching test;To explore the distribution characteristics of heavy metal elements in the horizontal direction,and then summarize the law of heavy metal leaching and migration from the tailings pond,and provide a basis for the tailings pond governance in the study area.Through the study,the main conclusions are as follows:1.Through the component test of the tailings pond and the soil column samples,it was found that the soil column samples and the tailings pond samples in the same mining area have similar elemental compositions and similar contents,reckoning that the heavy metal elements in the soil may come from the tailings pond.2.The heavy metal elements with high total dissolved amount in the leaching test are consistent with those of the tailings pond.The heavy metal composition of the tailings pond in the Dongguashan mining area is lower than that in other mining areas,while the total amount of heavy metals leached out is the highest among the three mining areas,and the pH of leaching liquid is also lower,those are related to the differences of composition of heavy metals in different mining areas,and also indicate that the mineral and elemental composition in the same mining area are similar.3.The leaching test results showed that as the infiltration depth increases,the leaching amount of heavy metals shows an upward trend;and with the increase of leaching time,the leaching amount of heavy metals rapidly decreases in a short time,and then the rate of decline becomes slower.The results show that under the effect of leaching,heavy metals in the surface layer of the tailings pond will infiltrate with the rainfall and migrate downward,and heavy metals will gradually leach away over time.4.Through the analysis of the heavy metal content of the soil column sample,the horizontal distribution of heavy metal elements was explored,and it was found that the heavy metal content in the soil column sample showed a decreasing trend with the increase of the distance from the tailings pond.It is speculated that this is the horizontal migration of heavy metals.the result of the horizontal migration of heavy metals.