Investigation On Pollution Of Water And Soil Around Sulfide-Mine Tailing Dams And Simulation Study On Soil Erosion Of Chemical Solution

Sulfide-mine tailing is one of the most important solid waste. Because of containing sulphur, it has strong chemical activity, is apt to release all kinds of ions, and makes pollutions to environment around the tailing bams. In this paper, taking some sufide-mine tailings dams as research objects along Diaojiang drainage-basin in Nandan County of Guangxi, tailings, water and silt of river bottom were investigated, and main releasing ions and environmental effect of sulfide-mine tailing were determined. On the basis of that, through indoor experimental simulation, soil eroding influences on chemical solutions and velocity of flow were studied. Chemical solution contains ions in waste water of mineral processing and tailings' releasing ions.Through the study, the following conclusions can be obtained.1. Concentrations of lead, arsenic, zinc, iron, sulphur or sulfate ion in the silt at the river bottom and water samples exceeded standards in various degree. Especially the degree of exceeding standard on arsenic is more serious than others. What is more, size composition of silt and content of heavy metal, arsenic, sulphur were obviously affected by adjacent tailings dams. The more close from the tailings dams, the lower of the content of big stones (above 2mm) in the silt, the more heavy of the content of fine-graded sands. Content of iron and arsenic in upriver silt of tailings dams was higher than that of adjacent downriver silt. And the more close from the tailings dams, the higher of thecontent of those in downriver silt of tailings dams. The enrichment degree of sulphur, iron and arsenic was lower than that of lead, zinc in the silt.2. Compared to pH value of original mixed solution, change of pH value of chemical solution was small after washing soil, but soil itself is acidity or weak base could be showed. Moreover, the amount and depth of rill affected quantity of sediment yield. The more obvious of the rill development, the great of the sediment yield, and the more serious of the degree of soil erosion.3. Effect of different valent cation solution was different on soil erosion. Under the condition of the same anions, the influence of Na⁺, Mn²⁺, Cr^<sub>3+, Cu²⁺ in different valent cation solution was the biggest on soil erosion, and that of NH₄⁺, Ca²⁺, Fe³⁺, Pb²⁺ was weaker, while the effect of Li⁺, Mg²⁺, Al³⁺, K⁺ was the weakest.4. Soil erosion was greatly influenced by the pH value. Under the acidic conditions, the more acute of acidity, the more serious of the destroying and eroding function on soil. Similarly, under acute alkali condition, the eroding degree are more serious with the rise of alkalinity. Especially soil erosion was greatly influenced by NaOH solution. Furthermore, Under the acute alkali conditions, the soil eroding influence of the solutions was more great by far than in the acidic conditions.5. The soil erosion rule was different because of different concentration of the solution. With the increase of concentration of kalium sulfate, the sediment yield was reduced, but contrary to that, the sediment yield affected by ammonium nitrate solution was enhanced. When the concentration of copper sulfate, chromium chloride and aluminum chloride solution was 0.25g/L, and that of zinc sulfate and ferric sulfate solution was 0.5g/L, the sediment yield was maximal, which showed soil erosion was serious by far. When the concentration of lead nitration and sodium nitration solution was 2g/L, the sediment yield was maximal, and when the concentration was above 2g/L, the higher of the concentration, the more of sediment yield, and the more serious of the degree ofsoil erosion6. Soil erosion was obviously influenced by velocity of water flow. With the increment of velocity of water flow, sediment yield is more heavy, but under the conditions of the experiment, when the velocity of water flow was enhanced five times than 100ml/min, the change of sediment yield was not distinct comparing to that of water and NaOH, KOH etc..Environmental problem of mine, water and soil con...