基于氧化还原-分步沉淀法的酸性矿山废水处理效果  

Treatment effect of acid mine drainage by the redox-stepwise precipitation method

作　　者：赖治廷 杨慧珠 石太宏[1] LAI Zhiting;YANG Huizhu;SHI Taihong(College of Environmental Science and Engineering,Sun Yat-Sen University,Guangzhou 510006,China;South China Institute of Environmental Sciences,Ministry of Ecology and Environment,Guangzhou 510535,China)

机构地区：[1]中山大学环境科学与工程学院,广州510006 [2]生态环境部华南环境科学研究所,广州510535

出　　处：《环境工程学报》2023年第5期1523-1532,共10页Chinese Journal of Environmental Engineering

摘　　要：为降低韶关市大宝山酸性矿山废水(AMD)的处理成本,采用氧化还原-分步沉淀法对矿山废水进行处理。结果表明:将石灰石分多次投入经过还原处理的废水中,在反应时间为45 min、转速为250 r·min^(-1)、废水pH为5时,可从AMD中回收高品质石膏;继续用NaOH溶液调节废水pH至5.5,控制曝气量为4 mg·L^(-1),曝气时间为45 min,通过氧化沉淀法和铁氧体法可分步回收废水中的Fe^(2+/3+),再向废水中加入NaOH溶液,调节废水pH至9.5,可沉淀回收废水中的Zn^(2+)、Cu^(2+);经过该工艺处理后,废水中各金属离子均低于国家污水综合排放标准(GB 8978-1996);该工艺处理1 t废水,可回收石膏5.4 kg(纯度85.72%),铁渣1.53 kg(w(Fe)=35.4%)、锌铜渣1.4 kg(w(Zn)=10.89%、w(Cu)=0.1%);废水中Fe^(2+/3+)、Zn^(2+)、Cu^(2+)回收率分别为84.3%、71.2%、46.2%,废水处理的药剂成本为4.1元·t^(-1),废水产生可回收资源产品收入为3.8元·t^(-1)。该工艺可从AMD中回收高品质石膏并分步回收废水中的金属,有效降低废水的处理成本,回收废水中的资源,实现环保与经济效益双赢的目标,并为AMD资源化处理提供理论指导。In order to reduce the treatment cost of the acid mine drainage(AMD)in Dabaoshan of Shaoguan City,the redox-step precipitation method was used to treat it.The results showed that high-quality gypsum could be recovered from AMD when the limestone was stepwise dosed into the wastewater after reduction treatment at the reaction time of 45 min,the rotation speed of 250 r·min^(−1)and pH 5.When the pH of the wastewater was further adjusted to 5.5 by NaOH solution,the aeration rate and time were 4 mg·L^(−1)and 45 min,respectively,Fe^(2+/3+)in the wastewater could be stepwise recovered by oxidation precipitation method and ferrite method.Afterwards,the pH of the wastewater was adjusted to 9.5 by NaOH solution addition,and Zn^(2+)and Cu_(2+)in the wastewater could be recovered through precipitation.After the treatment by this process,the metal ions in the wastewater were lower than the national comprehensive sewage discharge standard(GB 8978-1996);the process could recover 5.4 kg gypsum(purity 85.72%),1.53 kg iron slag(w(Fe)=35.4%),1.4 kg zinc-copper slag(w(Zn)=10.89%,w(Cu)=0.1%)from 1 t wastewater.The recovery rates of Fe^(2+/3+),Zn^(2+)and Cu_(2+)in wastewater were 84.3%,71.2%and 46.2%,respectively.The chemical cost of wastewater treatment was 4.1 yuan·t^(−1),and the income of recyclable resource products was 3.8 yuan·t^(−1).The process can recover high-quality gypsum from AMD and recover metals in wastewater step by step,effectively reduce the treatment cost of wastewater,recover resources in wastewater,achieve a win-win situation of environmental protection and economy,and provide a theoretical guidance for AMD resource treatment.

关 键 词：酸性矿山废水 石灰石中和法 石膏结晶 金属分步回收 

分 类 号：X703[环境科学与工程—环境工程]