利用中和渣复垦尾矿的可行性及其重金属污染特征研究  

Evaluating the feasibility and heavy metal pollution of reclaiming mine tailings using acid mine drainage neutralized sludge

作　　者：陈培江 池逸涵 蒋文平 庄荣传 熊明瑜 叶志鸿[2] CHEN Peijiang;CHI Yihan;JIANG Wenping;ZHUANG Rongchuan;XIONG Mingyu;YE Zhihong(State Key Laboratory for Comprehensive Utilization of Low-grade Refractory Gold Ores,Longyan 364200;School of Life Sciences,Sun Yat-sen University,Guangzhou 510275;Zijin Mining Group Company Limited,Longyan 364200)

机构地区：[1]低品位难处理黄金资源综合利用国家重点实验室,龙岩364200 [2]中山大学生命科学学院,广州510275 [3]紫金矿业集团股份有限公司,龙岩364200

出　　处：《环境科学学报》2022年第9期269-280,共12页Acta Scientiae Circumstantiae

基　　金：低品位难处理黄金资源综合利用国家重点实验室开放基金;国家重点研发计划项目(No.2018YFD0800700)。

摘　　要：有色金属矿在开采和冶炼的过程中会产生大量的尾矿渣和酸性矿山废水,后者被中和沉淀后成为中和渣.大量堆存的尾矿和中和渣会产生严重的安全和环境问题,亟需有效方法将其安全地处置或回收再利用.研究认为中和渣可以替代土壤作为植物的种植基质,进而缓解尾矿复垦中表土缺乏的困境,但该策略的可行性和安全性尚未经过系统的论证.本研究以紫金山铜矿堆浸废石边坡为对象,评估以中和渣替代自然土壤进行植被复垦的可行性,识别复垦过程中可能存在的限制植物生长的关键环境因子,分析中和渣中毒性重(类)金属元素的状况,比较不同种植方式和坡位对复垦效果的影响.结果表明,有机肥改良后的中和渣土壤氮、磷和钾的总量相对较好,孔隙度、容重和含水率和盐度持续改善.但其有机质总量的偏低,以及有机养分矿化速率较慢所导致的无机氮和有效磷的缺乏,很可能是限制植物生长的关键因素.中和渣所含重金属总量普遍保持稳定,产生二次的污染风险较小.相比机喷处理,人工穴播处理下的中和渣具有更好的养分条件和微生物多样性,但有pH下降和铜、铁和锰等重金属的有效性上升的趋势.本研究的结果表明,以中和渣作为土壤基质进行尾矿复垦是相对安全可行的,但仍需长期关注其pH的变化,并适当增加有机质的添加量和利用微生物菌剂促进其中养分的矿化.Acid mine drainage(AMD)and tailings are produced in large quantities during the mining and smelting of nonferrous metals.Neutralized sludge(NS)is produced when AMD is neutralized and precipitated by alkaline chemicals.Both tailings and NS can pose severe safety and environmental issues,which demand effective measures of disposing or recycling.Based on its physicochemical properties,NS might be used as a potential soil substitute to tackle the scarcity of natural soil in mine revegetation.However,the effectiveness and safety of this strategy needs to be elaborated and systematically validated.Therefore,this study aimed to evaluate the feasibility of mine reclamation using NS as soil substitute,to reveal the key environmental factors limiting plant growth,to analyze the potential variation of the contents and bioavailability of toxic metal(loid)s and to compare the performance of different planting methods and slope positions on the reclamation.The field trial was conducted on a dump slope of waste rocks produced in the biological heap leaching site of Zijinshan Gold-copper Mine.Result showed that the total contents of nitrogen,phosphorus and potassium are sufficient and stable in NS amended with organic manure.The physicochemical properties of NS were also improved gradually.However,inadequate inorganic nitrogen and bioavailable phosphorus,as well as relatively low organic carbon level should be the key restricting factors for plant growth and soil fertility restoration during the reclamation process.This was likely to be caused by the limited mineralization of organic nutrients in NS due to the lack of certain functional groups of soil bacteria.During the entire experimental period,the contents of metal(loid)s remained stable in NS,which was thus unlikely to cause secondary pollution.The manual-seeding treatment exhibited better soil nutrient status and bacterial diversity than the mechanical spraying treatment.However,the bioavailable contents of copper,iron and manganese increased in the manual-seeding treatmen

关 键 词：矿山复垦 中和渣 土壤肥力 重金属 土壤微生物 

分 类 号：X53[环境科学与工程—环境工程]