CO_(2)协同生物法处理铅锌选矿废水的应用

Application of CO_(2) and biological synergistic treatment of lead-zinc mineral processing wastewater

有色金属采选耗水量大,产生的废水量多,每年产生的废水量约占全国工业废水总量的1/10。随着国内对环保要求的日益提高,国家对新建选矿项目用新水单耗以及水循环利用率均提出了要求。目前国内许多大型选厂普遍将选矿废水输送至尾矿库自然降解后回用,随着近年来尾矿库建设批复的日渐缩紧,上述方法无法持续。经济、高效地处理选矿废水并进行回用是有色金属采选企业需要解决的重要课题。介绍了CO_(2)协同生物法处理铅锌选矿废水的应用案例,其工程总规模30000 m^(3)/d。对CO_(2)调节pH的预处理系统及采用DAT-IAT工艺的生化处理系统进行重点介绍。工程运行数据显示,该处理工艺可将废水COD_(Cr)稳定处理至20 mg/L,铅、锌离子亦能达到《铅锌工业污染物排放标准》(GB 25466—2010)的相关要求。采用该系统对某铅锌选矿厂的选矿废水进行处理并回用于选矿工艺,与清水选矿品位基本一致,实现了废水的无害化与资源化利用。污水处理运行成本约为2.50元/m^(3),综合效益明显。

Non-ferrous metal mining and beneficiation consumes a large amount of water and produces a lot of wastewater,which accounts for about 1/10 of the total amount of industrial wastewater in China every year.With the increasing requirements for environmental protection,China has put forward requirements for new mineral processing projects in terms of unit consumption of new water and water recycling rate.At present,many large concentration plants in China generally convey the beneficiation wastewater to tailing pond for natural degradation and then reuse.With the tightening of approval of tailing pond construction in recent years,the above method will not be sustainable.Economical and efficient treatment and reuse of mineral processing wastewater is an important issue that needs to be addressed by non-ferrous metal mining enterprises.The application case of CO_(2) combined with biological treatment of lead-zinc beneficiation wastewater with a total project size of 30000 m^(3)/d was presented.The pretreatment system of CO_(2) regulating pH and the biochemical treatment system with DAT-IAT process were highlighted.The project operation data showed that the treatment process could stabilize wastewater COD_(Cr) to 20 mg/L,the lead and zinc ions met the requirements of Emission Standard of Pollutant for Lead and Zinc Industrial(GB 25466-2010).The system was used to treat the mineral processing wastewater of a lead-zinc concentrator and reuse it in the beneficiation process.The grade was basically the same as the clear water beneficiation grade,realizing the harmless and resourceful utilization of the wastewater.The operating cost of wastewater treatment was about RMB 2.50/m^(3),with obvious comprehensive benefits.