铅锌冶炼厂冶炼渣淋溶释放的铅在红壤中垂直迁移特征

Characteristics of vertical migration of Pb released from smelting slag of lead-zinc smelter in red soil area

为了揭示红壤地区铅锌冶炼厂冶炼渣中的铅淋溶释放后在堆放场地土壤中的垂直迁移特征,以湖南株洲某铅锌冶炼厂冶炼渣堆放场地土壤为研究对象,采用等温吸附及土柱淋溶模拟试验探究了冶炼渣淋溶释放的铅在冶炼渣堆放场地土壤中的吸附与垂直迁移特征。结果表明:堆放场地土壤对冶炼渣淋溶释放的铅有较强的吸附能力,吸附由低能位和高能位共同控制,其中高能位对铅的最大吸附量为7392.771 mg/kg,低能位对铅的最大吸附量为13518.278 mg/kg,说明铅在堆放场地土壤中不易迁移。10 cm厚冶炼渣淋溶模拟释放的铅在堆放场地土壤中缓慢向下迁移,较长时间内(3 a)冶炼渣淋溶释放的铅主要富集在30 cm以内的土层中,30 cm处淋出液中的铅在0.006 mg/L内浮动;可采用多物理场仿真软件COMSOL对铅的垂直淋溶迁移过程进行定量描述和预测,预测结果与淋溶试验实测值基本相符,3 a内淋出液中的铅实测值均匀分布于模拟值曲线两侧,COMSOL预测结果进一步表明冶炼渣淋溶9 a释放的铅仍主要富集在30 cm以内的土层中,但呈现缓慢下移趋势。

The soil of the slag stacking site of a lead-zinc smelter in Zhuzhou,Hunan was taken as the research object to reveal the vertical migration of Pb from lead-zinc smelter slag in red soil after leaching.Isothermal adsorption and column leaching experiments were used to investigate the adsorption and vertical migration characteristics of Pb released by leaching of smelting slag in the soil of smelting slag stacking site.The results showed that the soil in the stacking site had a strong adsorption capacity for Pb released from the leaching slag,and the adsorption of the soil was controlled by both low energy and high energy levels.The maximum adsorption capacity for Pb at the high energy level was 7392.771 mg/kg,while that at the low energy level was 13518.278 mg/kg,which meant that Pb migrated slowly in the soil.The Pb released by the simulated leaching of 10 cm smelting slag migrated slowly downward in the soil and was mainly enriched in the soil layer within 30 cm in a long time(3 a).The Pb concentration in the effluent at 30 cm fluctuated within 0.006 mg/L.The leaching vertical migration process could be quantitatively described and predicted by software COMSOL.The predicted results were basically consistent with the measured values in the 3 a leaching test,which was uniformly distributed on the simulated value curve.The prediction result of COMSOL further indicated that Pb released by smelting slag leaching for 9 a was still mainly concentrated in the soil layer within 30 cm,and the Pb in the soil moved slowly downward in the soil over time.