Release And Stabilization Of Heavy Metals From Dump And Tailings Of Copper Mine, Jiangxi Province

Mining and smelting metal mine can cause environmental pollution. The waste dump and tailings of copper mine in Jiangxi province were used as research objects in this paper, and study on release and environmental pollution risks of heavy metals according to background pollution investigation. By doing stabilization experiments of heavy metals from dump and tailings, selected the best ratio of stabilizers and curing time, and using different leaching methods evaluated the stabilization effects.The main conclusions of the study are as follows:(1)Dump and tailings of copper mine were found to be acid faintly. The most contents of Cu, Zn, Pb, Ni, Cd from dump were 1395.50 mg/kg, 1401.80 mg/kg, 408.90 mg/kg, 13.74 mg/kg, 2.65 mg/kg. On the other hand contents of Cu, Zn, Pb, Ni, Cd from tailings were 3014.8 mg/kg, 1089.00 mg/kg, 200.00 mg/kg, 7.74 mg/kg, 5.38 mg/kg. Leaching toxicity experiments showed that dump and tailings were not hazardous waste. Because the p H of dump and tailings was less than 6, they were categorized as Class II of general industrial solid wastes.(2)Release experiment showed that p H could control the release of heavy metals of dump and the tailings. Acidic condition was beneficial to the release of heavy metals from the dump and tailing. The release range of Cu from dump was 0.0129 mg/L to 0.0402mg/L, the release range of Pd was from 0.0246 mg/L to 0.0406mg/L, the release range of Zn was from 0.0161 mg/L to 0.1499mg/L, the release range of Ni was from 0.0082 mg/L to 0.0231mg/L, the release range of Cd was from 0.0063mg/L to 0.0128 mg/L. The release range of Cu from tailings was from 0.0477 mg/L to 0.3845mg/L, the release range of Pd was from 0.0016 mg/L to 0.0054 mg/L, the release range of Zn was from 0.0249 mg/L to 0.1696 mg/L, the release range of Ni was from 0.0022 mg/L to 0.0071 mg/L, the release range of Cd was from 0.0042 mg/L to 0.0406 mg/L. Neutral condition(p H=7.0) was not beneficial to the release of heavy metals. Ni and Cd were not detected in the leaching liquid.(3)By using single factor index method assessed the pollution of heavy metals from dump and tailings. The results showed that the all samples were at V level. Then using potential ecological risk index method evaluated the potential ecological risk of study area.The received results showed that most of the sampling points had serious ecological threats.(4)By using Fly Ash- Peat- Rice Husk Ash composite stabilizer,stabilize the heavy metals from dump and tailings.The results showed that fly ash and rice husk ash played a major role in stabilization. Adding peat to improve the efficiency of stabilization was not obvious. The best stabilization condition was adding 15% Fly Ash and 15% Rice Husk Ash, at 28 days curing time.(5)Using horizontal vibration method, Sulphuric acid &Nitric acid method, and SPLP method evaluated the effects of stabilization. The results showed that stabilization efficiencies of Cu, Pb and Zn were above 93.8%. Fly ash and rice husk ash could stabilize heavy metals of this type of solid waste from copper mine effectively.