重金属沉渣土著微生物浸出后余渣的潜在毒性

在pH值为3.0、温度为30 ℃、矿浆质量分数为7%的优化浸出条件下，通过摇瓶试验，结合X射线衍射分析、BCR法3步连续提取，研究了土著微生物浸出重金属沉渣后余渣中重金属的潜在毒性。结果表明：土著微生物浸出7 d后，沉渣中Cd，Mn，Cu，Pb，Zn含量分别由原来的4 530，7 650，830，29 530，62350 mg/kg降低至730，1280，390，13 810，15650 mg/kg.浸出过程沉渣中Cd，Mn，Cu，Pb，Zn等重金属的酸可提取态相对含量显著降低，残渣态相对含量提高.余渣环境活性和潜在危害低于《危险废物鉴别标准》（GB 5085.3-2007）的规定，土著微生物浸出能有效实现重金属沉渣的资源化和无害化.

Potential Toxicity of the Residues from Indigenous Microorganisms Leaching of Heavy Metal Sediment

Shaking flask experiments were used to study the indigenous microorganisms leaching of heavy metals from sediment in the optimum conditions,which were determined to be pH = 3.0,65℃ and 7% pulp density. Residues from the bioleaching were analyzed through XRD and three-stage BCR sequential extraction procedure. Results show that heavy metal（Cd, Mn, Cu, Pb, Zn） contents sharply decrease over 7 days leaching,from 4 530 mg/kg,7 650 mg/kg,830 mg/kg,29 530 mg/kg,62 350 mg/kg to 730 mg/ kg, 1 280 mg/kg,390 mg/kg,13 810 mg/kg, 15 650 mg/kg respectively. Acid extractable percent content decreases remarkably during the bioleaching process;meanwhile,residual form percent content rises obvi- ously. The environmental availability and potential risk of heavy metals are less than the standards listed in Hazardous Waste Distinguishable Standard （GB 5085.3--2007）. Indigenous microorganisms can effi- ciently implement the resources and harmlessness of heavy metals in sediment.