Valorisation of acid mine drainage treatment sludge as remediation component to control acid generation from mine wastes,part 1: Material characterization and laboratory kinetic testing

In operating mines, acid mine drainage (AMD) is often treated using lime treatment. This process generates a significant amount of sludge that contains metal hydroxide precipitates, gypsum, and unreacted lime. The sludge may have interesting geotechnical and geochemical properties to be used as a part of covers (oxygen barriers) to prevent AMD generation from waste rocks and tailings. The main results of a project aiming to evaluate the use of sludge from the Doyon mine site (Canada) as a material in mine site rehabilitation are presented. The first part of the project involved detailed characterization of sludge, waste rock, and tailings samples. Then, laboratory column leaching tests were performed to evaluate the performance of the mixtures to control AMD produced by tailings and waste rocks. It was found that a sludge–waste rock mixture placed over waste rock reduces the metal loads in the column effluent, which remained acidic, as well as a mixture of sludge and tailings deposited over tailings can reduce metal content in effluents from tailings.     

铀水冶厂废水治理的主要技术、措施与展望(待续)

简述了用于处理废水、废矿浆的石灰乳中和沉淀法，用于处理尾矿坝废水的软锰矿吸附法、曝气法和钡盐沉淀一氢氧化物沉淀絮凝载带法。着重介绍了废水、废矿浆坝前一次性综合处理新工艺的特点、适应性和应用前景。实践证明：通过采用新工艺和新技术，综合利用资源，以废治废，循环工艺用水，加强生产管理等一系列综合防治措施，可以完善废水治理和建立简易可行、费用少、效果好的废水处理体系，使废水达到标本兼治的目的。     

铀水冶厂废水治理的主要技术措施与展望 （续完）

简述了用于处理水，废矿浆的石灰乳中和沉淀法，用于处理尾矿坝废水的软锰矿吸附法、曝气法和钡盐沉淀氢氧化物沉淀絮凝载带法。着重介绍了废水、废矿浆坝前一交 综合处理新工艺的特点，适应性及应用前景。     

Field Study of the Chemical and Physical Stability of Highly Sulphide-Rich Tailings Stored Under a Shallow Water Cover

Highly sulfide-rich (approximately 83 % pyrite), potentially acid-generating mine tailings were sub-aqueously deposited in the Don Rouyn old quarry pit from 1997 to 2000. The site covers approximately 7 ha near Rouyn-Noranda, Quebec. Various in situ measurements and laboratory tests were performed during the summer and autumn of 2008, 2009, and 2010 to: characterize tailings samples; monitor water quality in the final effluent, shallow water cover, and groundwater around the pit, and; study tailings erosion and resuspension. In situ measurements included the vertical profile and spatial distribution of pH, temperature, dissolved oxygen, electric conductivity, and redox potential. Suspended tailings, wind speed, and direction were monitored. Groundwater, cover water, and final effluent water samples were chemically analyzed and suspended sediment concentrations (SSCs) was determined. Physical, mineralogical, and chemical tailings properties were also determined. Results show that the quality of the groundwater, cover, and effluent waters complied with Canadian and Quebec regulations. SSCs were also within regulation limits. No association was found between SSC and hydrodynamic conditions (wind speed, fetch, etc.). Although theoretical calculations indicated a critical wind speed of at least 10 m/s for tailings resuspension, suspended sediment was observed for wind speeds at <10 m/s.     

某钨钼选矿废水水质调研及混凝沉降试验研究

某钨钼选矿厂的选矿废水中含有超微细矿物颗粒和残留的选矿药剂,产生的浊度、悬浮物均较高,影响其直接回用,针对这一问题,首先对该厂的选矿废水水质进行了调研,摸清水质特征,继而进行了混凝沉降药剂探索试验,发现复配的BK-A混凝剂具有较好的沉降效果,随后又进行了现场混凝沉降优化试验研究。试验研究结果表明:BK-A混凝药剂最佳反应条件为:沉降pH值9～10,BK-A药剂投加量20～25mL/L,PAM投加量6mL/L,处理后的尾矿库选矿废水浊度和悬浮物指标基本能达到清水水质指标,尾矿库废水中硅酸根离子能稳定降至100mg/L左右。     

Valorization of acid mine drainage treatment sludge as remediation component to control acid generation from mine wastes,part 2: Field experimentation

The possibility of using acid mine drainage (AMD) treatment sludge as a cover component to control AMD generation from mine wastes was investigated through laboratory characterization and kinetic column testing (companion paper). The results showed that mixtures of sludge and waste rock, and sludge and tailings, may be integrated in an AMD prevention and control strategy at Doyon mine site (northwestern Quebec, Canada). In order to further investigate these scenarios in realistic climatic conditions, instrumented field test cells were installed on site to evaluate the performance of the mixtures to control AMD generation from tailings and waste rock under natural field conditions. The main findings from two seasons of monitoring are presented in the paper. The waste rock-sludge mixture placed over waste rock was able to reduce the generation of AMD from the waste rock, therefore confirming lab results, and was able to produce a neutral effluent with low concentrations of dissolved metals. The tailings-sludge mixture placed over tailings, with an evaporation protection layer, maintained a high volumetric water content and reduced sulphide oxidation from the tailings as exhibited by a neutral effluent. Monitoring of the field cells will continue to provide valuable information on the possible sludge valorization options.     

含镉、锌矿坑水深度处理工艺试验研究及工程应用

针对福建某矿山含镉、锌矿坑水经石灰中和处理后的出水水质不能达到企业的深度处理水质要求,开展工艺优化试验研究及提标升级改造。试验考察了石灰中和、石灰中和—硫化沉淀、混凝—石灰中和法去除镉、锌的效果,并进行工业调试及运行。结果表明,混凝—石灰中和处理工艺综合处理效果较好,外排水中Cd、Zn浓度分别低于0.005、0.1 mg/L,去除率均大于99.40%,吨水处理成本为2.15元,不增加处理成本的同时实现Cd、Zn减排。该方法实现"以废治废",环境效益显著。     

一种增大尾矿库回水量的方法

在分析尾矿库回水量组成的基础上,以内蒙古锡林郭勒盟地区某湿排尾矿库为例,提出了一种采用悬浮球增大回水量的方法。理论分析和对比试验验证表明,该方法能够大大减少蒸发量,增大尾矿库回水量,操作简单,可在缺水地区的尾矿库运行管理中推广应用。     

铀堆浸废水中和沉渣减容与改性方法研究

在传统石灰中和处理法的基础上，提出了酸法难浸废水用“石灰石-石灰两步中和-沉渣循环”的流程进行处理。废水先与廉价的石灰石接触反应，使废水中的强酸中和并使铁、铝等金属离子在较低pH值下形成氢氧化物，再用石灰乳进一步中和到要求的pH。生成的沉淀物（沉渣）在过程中不断循环。该方法与一次石灰中和法相比，试剂费用节省1／3，沉渣生成量（以体积计）减少2／3，并且沉渣的过滤和沉降性能也有所改善。本工作还对沉渣减容与改性的机理进行了研究探讨。     

Neutralizing Coal Mine Effluent with Limestone to Decrease Metals and Sulphate Concentrations

Abstract.   This paper describes pilot scale tests of a novel process for the neutralisation of acidic mine water. Leachate from a waste coal dump was neutralised with limestone, and iron, aluminium, and sulphate were removed. Specific aspects studied were: the process configuration; the rates of iron oxidation, limestone neutralisation, and gypsum crystallisation; the chemical composition of the effluents before and after treatment; the efficiency of limestone utilisation; and the sludge solids content. The acidity was decreased from 12,000 to 300 mg/L (as CaCO₃), sulphate from 15,000 to 2,600 mg/L, iron from 5,000 to 10 mg/L, aluminium from 100 to 5 mg/L, while the pH increased from 2.2 to 7.0. Reaction times of 2.0 and 4.5 h were required under continuous and batch operations respectively for the removal of 4 g/L Fe (II). The iron oxidation rate was found to be a function of the Fe (II), hydroxide, oxygen, and suspended solids (SS) concentrations. The optimum SS concentration for iron oxidation in a fluidised-bed reactor was 190 g/L. Up-flow velocity had no influence on the rate of iron oxidation in the range 5 to 45 m/h. Sludge with a high solids content of 55% (m/v) was produced. This is high compared to the typical 20% achieved with the high density sludge process using lime. It was determined that neutralisation costs could be reduced significantly with an integrated iron oxidation and limestone neutralisation process because limestone is less expensive than lime, and a high-solids-content sludge is produced. Full scale implementation followed this study.     

某尾矿库排洪回水系统渗水治理措施

某山谷型尾矿库排洪设施采用溢水塔-隧洞方案,在已停止使用的3#支洞有少量渗水,渗水水质变浑后,水泵、管道无法承受,夹有尾砂悬浮物超标的渗水排入下游河道,引发了轻污染事件。对渗水原因进行分析,提出堵塞3#支洞并进行黄土覆盖的方案,解决了渗水问题。     

武山铜矿选矿尾矿浆中和处理采矿井下酸性废水的研究

利用选矿尾矿浆中的残留石灰中和处理采矿井下酸性废水，该法应用到武山铜矿，可充分利用现有的尾矿输送和尾矿库设施，无需新建污水处理站和堆渣库，处理后的外排水稳定达标。此工艺具有处理工艺简单，运行费用低，管理方便等特点，废水处理成本仅为0．17元／t，比单独治理废水节约1．12元／t.     

伊宁铀矿硝酸根废水自然蒸发处理可行性探讨

伊宁铀矿含硝酸根地浸废水的现场中和沉淀试验表明,中和沉淀后沉淀母液中的ρ（U）随ρ（NO3^-)的增加而增加,当ρ（U）为1．5－2．0mg/L时,只有ρ（NO3^-）小于０．５g/L时,沉淀母液中的ρ（Ｕ）才可降到0.1mg/L;在预定设置废水自然蒸发池地段土壤的渗透系数较大,约为1．0－1．1m/d;而对废水中和沉淀浆体的渗透系数可降到0．03－0．16m/d。自然蒸发池设置防漏层可减少铀以及可溶性硝酸盐和铵对地下水的污染。     

某铀矿尾矿库废水处理工艺研究

分析某铀矿尾矿库废水组成和主要污染因子,通过试验研究,确定了处理该尾矿库废水的工艺流程,即石灰乳中和-锰砂吸附废水处理工艺.经处理,废水中铀、镭、锰、氟、pH值均达到排放标准.     

采用高密度污渣返回法处理铀矿山酸性废水的研究

介绍了采用高密度污渣返回法处理铀矿山酸性废水工艺流程。该流程与常规法比较,有以下优点:污渣沉淀速度快,压缩性能好,w (固体)高,没有返溶现象,并且石灰用量减少约20% 。从而解决了普通石灰中和法产生大量污渣及难以处置的问题     

絮凝沉降—臭氧氧化法处理硫化铜选矿废水试验

选矿厂废水排放量大,废水中固体悬浮物、浮选药剂、重金属离子等物质含量高,废水外排处理成本高且易造成二次污染,直接回用又影响浮选指标。因此,实现选矿废水的循环利用对节约有限的水资源,减少环境污染具有重要意义。模拟废水浮选试验结果表明:废水中的Al³⁺、Fe3³⁺对硫化铜矿浮选有显著抑制作用,Pb²⁺、Zn²⁺、Fe²⁺对硫化铜矿浮选影响较小;随着丁基黄药和Z-200浓度的增加,捕收剂对铜的选择性变差。采用絮凝—臭氧氧化工艺处理安徽某铜矿山选矿废水试验结果表明:聚丙烯酰胺对废水中的重金属离子及悬浮物具有显著的沉降效果;在整个pH期间,臭氧对丁基黄药去除效果显著,pH=8时,臭氧对Z-200去除效果最佳。采用絮凝沉降—臭氧氧化联合工艺处理后的选矿废水用于浮选试验,其浮选指标略低于清水浮选指标,远优于废水直接回用浮选指标。即应用此工艺处理硫化铜浮选总尾矿水,可有效降低水中不利组分的含量,实现水资源的高效利用。     

深切割区尾矿库排洪系统"空天地一体化"行洪能力评估

尾矿库作为矿山重大危险源，其排洪系统行洪能力直接影响着尾矿库的稳定性。为解决传统方法对深切割区尾矿库排洪系统行洪能力评估效率低、精度差的问题，以川西高原高山峡谷区某尾矿库为例，首先采用高分遥感技术获取尾矿库汇水区信息，然后利用无人机摄影测量和三维激光扫描技术提取现状库身长度，建立尾矿库DEM，计算调洪库容，最后进行调洪验算，构建了基于“空天地一体化”的深切割区尾矿库排洪系统行洪能力评估方法。实例计算结果表明：尾矿库排洪系统最大泄流量出现于时序3.15 h，泄流量21.58 m³/s，所需调洪库容3.52万m³，小于尾矿库具备的调洪库容4.62万m³，表明排洪系统行洪能力满足相应等级要求，同时也体现出该方法在深切割区尾矿库排洪系统行洪能力评估中具有优越性和可复制性。     

高密度泥浆法处理矿区污水的应用与实践

通过对新桥矿业公司生产污水的分析与试验,针对性地采用高密度泥浆法处理酸性污水,能够达标排放,取得经济、环保双效益。     

锑矿尾矿库重金属污染特征分析

为阐明我国锑尾矿中重金属的污染特征及其对周边环境的影响,采用标准指数法分析了典型锑矿采选企业的锑尾矿主要成分和重金属含量.结果表明,锑尾矿不属于我国已明确的危险废物,但需进一步判定是否属于第Ⅱ类一般工业固体废物.此外,采用水质指数法对锑尾矿库内废水、尾矿库渗滤液和尾矿库周边土壤中重金属浓度进行了评价.结果表明,尾矿库内...     

某铀尾渣库退役治理覆盖系统设计

结构合理的覆盖系统是有效降低铀尾矿(渣)库氡析出率的重要措施。在总结国内外铀尾矿(渣)库覆盖系统研究成果及发展历程的基础上,根据辽宁某铀尾渣库现场覆土降氡试验成果,提出该尾渣库退役治理多层覆盖系统结构型式设计,并确定了覆盖材料、厚度和组成。设计的覆盖系统结构型式简单,施工方便,满足将氡析出率降至规定限值以下的要求。