铁尾矿路用对土壤环境质量影响及安全修复研究

为分析铁尾矿路用对道路沿线土壤环境质量影响的程度,对铁尾矿化学成分及有害物质进行测定,以秦巴山区的山地黄棕壤作为道路建设的耕土环境,把铁尾矿按70%~90%的推荐比例掺入,铁尾矿中的重金属按照最不利的全浸入式扩散进行分析,对黄棕壤中重金属含量超过限制要求的重金属进行安全修复,使铁尾矿道路沿线黄棕壤的重金属含量满足限制要求。结果表明:铁尾矿硫化物含量高达到2.89%,不满足配制混凝土的硫化物限量要求;铁尾矿路用的土壤中重金属Cr最大含量103.24 mg/kg、Cu最大含量116.4 mg/kg,国评标准污染等级均为Ⅱ级,其余重金属元素含量都在国家标准正常范围以内;高生物量的非超富集植物、细菌微生物、城市的污泥、工业粉煤灰(5%粉煤灰+50%尾矿砂+45%黄褐土)能够很好修复重金属Cr、Cu污染的土壤;含钙类物质的钝化剂处置重金属Cr、Cu污染效果好,腐殖酸、凹凸棒土、膨润土可以钝化土壤中的重金属Cu;高生物量非超富集植物、微生物钝化剂联合使用,具有更好的修复效果;当控制铁尾矿掺加比例不超过73%时,铁尾矿道路沿线的土壤重金属含量能够满足国家标准限值的要求。

Research on the Impact of Iron Tailings Road Usage on Soil Environmental Quality and Safety Remediation

To analyze the degree of impact of iron tailings road use on soil environmental quality along the road,this study determined the chemical composition and harmful substances of iron tailings,taking the yellow brown soil of the Qinba Mountains as the cultivated soil environment for road construction,the iron tailings are mixed in the recommended ratio of 70% to 90%,the heavy metals in the iron tailings are analyzed according to the most unfavorable total immersion diffusion,and the heavy metals in the yellow brown soil whose content exceeds the limit are safely repaired to make the heavy metal content of the yellow brown soil along the iron tailings road meets the requirements.The results showed that the sulfide content of the iron tailings reached 2.89%,which does not meet the sulfide limit requirements for the prepared concrete.The maximum content of heavy metal Cr in the soil used in iron tailings roads is 103.24 mg/kg,and the maximum content of Cu is 116.4 mg/kg.The pollution level of the national assessment standard was grade Ⅱ,and the content of other heavy metal elements was within the normal range of the national standard.High-biomass non-super-enriched plants,bacterial microorganisms,urban sludge,industrial fly ash(5% fly ash+50% tailings sand+45% yellow brown soil)can repair heavy metals Cr and Cu contaminated soil.The passivating agent containing calcium materials has good effect on the treatment of heavy metals Cr and Cu.Humic acid,attapulgite and bentonite can passivate the heavy metal Cu in the soil.The combination of high-biomass non-super-enriched plants and microbial deactivator has a better repair effect.When the proportion of iron tailings is controlled to be less than 73%,the heavy metal content of in soil along the road of the iron tailings can meet the requirements of the national standard limits.