Total mercury in terrestrial systems (air-soil-plant-water) at the mining region of San Joaquín,Queretaro, Mexico

Deficient management of cinnabar mining left the San Joaquín region with high concentrations of mercury in its soils (2.4 – 4164 mg kg^-1). Numerous cinnabar mines have contributed to the dispersion of mercury into agricultural (0.5 –314 mg kg^-1) and forest (0.2 – 69 mg kg^-1) soils. Sediments are a natural means of transportation for mercury, causing its spreading, especially in areas near mine entrances (0.6 – 687 mg kg^-1). The nearness of maize crops to mines favors mercury accumulation in the different plant structures, such as roots, stems, leaves, and grain (0.04 – 8.2 mg kg^-1); these being related to mercury volatilization and accumulation in soils. Mercury vapor present in the settlements could indicate a constant volatilization from lands and soils (22 – 153 ng m^-3). The mercury levels found in the soils, in maize grain, and in the air resulted greater than the standards reported by the Official Mexican Norm (NOM) and the World Health Organization (WHO). Mercury in rainwater is due mainly to the presence of suspended atmospheric particles, later deposited on the surface (1.5 – 339 μg |^-1). Mercury dissolution was found in the drinking water (10 – 170 ng |^-1), with concentrations below those established by the NOM and the WHO. The contamination existing in the San Joaquín region does not reach the levels of the world’s greatest mercury producers: Almaden (Spain) and Idrija (Slovenia). It is, however, like that found in other important second degree world producers such as Guizhou (China). The population of San Joaquín, as well as its surrounding environment, are constantly exposed to mercury contamination, thus making a long term monitoring necessary to determine its effects, especially to people.     

关于磷石膏尾矿库安全专篇的研究

磷石膏尾矿库是以磷石膏渣堆积起来形成的尾矿库,其安全问题一直是磷化工企业及安全生产管理部门非常关心的问题。根据《尾矿库安全监督管理规定》,尾矿库工程在设计阶段应该编写安全专篇,需要对尾矿库及尾矿坝稳定性、尾矿库防洪能力及排洪设施和安全观测设施的可靠性进行充分论证。3个方面的内容紧密联系,其是否安全可靠决定着尾矿库是否安全运行。针对磷石膏尾矿库的安全专篇问题,分析了专篇中的关键技术内容,对防洪计算、稳定性计算和安全监测分析等方面的本质问题进行了探讨,并将这三者作为一个系统进行分析总结。通过对湖北某磷石膏尾矿工程安全专篇的编写与分析,对具体的技术方法给出了说明。目前尾矿库工程安全问题受到了广泛的关注,其结果提供了比较完整的具体经验,采用的方法和得出的结论对相关工程可以起一定的借鉴作用。     

米箭沟尾矿坝加高方案渗流场数值分析

米箭沟尾矿坝为了进行加高设计而进行了尾矿库区的地质钻孔勘探。基于实际钻孔勘探成果的最佳反演分析各分区-尾矿砂、风化岩体和初期坝堆石体的模型渗透参数和加高设计方案,采用三维有限元数值计算方法,应用自主开发的3D-Seepage-Stress程序进行了该尾矿坝加高后渗流场数值分析,得出渗流场各要素分布图。可以看出,在此加高方案下,尾矿坝库区浸润线和溢出点都很高,不利于尾矿坝的稳定安全和运行管理。为此提出了在加高方案设计中加强排渗设施设计的初步方案与建议。     

尾矿坝稳定性的可靠度分析

以极限平衡理论和传统的安全系数方法为基础,将可靠度理论引入尾矿坝稳定性分析中。通过敏感性分析和可靠度计算分析发现,尾矿材料的内摩擦角的变异性将显著地影响尾矿坝稳定性分析的可靠指标,重度的变异性对可靠指标的影响大于粘聚力的变异性的影响。简述了尾矿坝稳定性分析中利用可靠度理论的重要性,并建议在尾矿坝的可靠度分析中,将尾矿材料的抗剪强度指标c, 和重度 作为基本随机变量。     

铜镍尾矿砂微波加热硫酸溶解实验研究

通过尾矿砂微波加热硫酸溶解新方法的实验,研究了硫酸浓度、液固比及反应时间等因素对尾矿砂酸蚀率的影响。结果显示,在无需搅拌的情况下,微波加热实验的最佳条件酸浓度5mol/L、液固比5.0mL/g都较传统水热法有优势,在反应时间上,微波加热15min就能达到传统水热法2～3h的效果。在酸蚀率相同的情况下,微波加热所用时间仅为传统水热法的1/6,而所用的酸浓度、液固比都较传统水热法小很多。先对尾矿砂直接微波辐照一段时间,然后再加入硫酸进行微波辐照加热溶解,能够促进尾矿砂的溶解,提高尾矿砂的酸蚀率。微波加热条件下,尾矿砂在硫酸浓度8mol/L、液固比5.0mL/g条件下无需搅拌,反应1h后,除透闪石没有完全溶解外,绝大部分的矿物被溶解。与传统加热方式相比,微波加热可显著提高尾矿砂酸溶解速率。     

内蒙古阿右旗低品位镍矿石可选性试验研究

该试验对低品位镍矿进行了选矿试验研究。结果表明：采用一段磨矿、细度-0．074mm 85％、先反浮选脱泥、脱泥后的尾矿进行粗选,两次粗扫选、三次精选流程;浮选药剂采用碳酸钠、2^#油、CMC、硫酸铜、丁基黄药、J-622;试验指标为：原矿镍品位0．18％、浮选精矿镍品位3．15％、浮选尾矿品位0．11％、反浮选产品镍品位0．19％、精矿镍回收率39．17％。该研究结果为该矿石的可选性评价提供了技术依据。     

猫岭-王家崴子金矿采矿废料的酸化潜力研究

为控制金矿开采废岩和选冶废料的酸化 ,利用净产酸量、净产酸势实验和柱淋溶实验 ,研究了猫岭 王家崴子金矿区采矿废石和尾矿的酸化情况。结果表明 ,在废石和尾矿的堆放过程中会发生酸化 ,且废石的产酸量远高于尾矿的产酸量 ,氰化尾矿的产酸量高于浮选尾矿的产酸量。但是 ,12 0天的淋溶实验表明 ,各种采选废物在短期内酸化现象不明显 ,与本区采矿废石和尾矿低的含硫量和系统中的缓冲能力及其外部环境因素有关 ,也反映了废物漫长的酸化过程。本研究结果为金矿开发废碴的环境管理和酸化控制提供了科学依据。     

冶炼废渣综合回收铀、铌、钽和锡

根据某冶炼尾渣的成分和矿物特性,研究了铀、铌、钽和锡的回收工艺。开发出酸浸提铀-重选抛尾-弱磁选回收铌、钽一强磁选除铁回收锡的联合工艺流程。铀浸出率大于80％;铌、钽品位大于31％,回收率大于80％;锡精矿品位大于62％,回收率大于65％,锡精矿经放射性去污后,其放射性水平基本符合有色冶金行业标准。     

Long-term coupled behaviour of cemented paste backfill in load cell experiments

A pressure cell apparatus has been developed in this research work to study the long-term hydro-mechanical behaviour of cemented paste backfill (CPB) cured under applied stress. The samples are cured for 7, 28, 90 and 150 days and the evolution of their mechanical, hydraulic, physical and microstructural properties is studied. Also, the suction, temperature and electrical conductivity are monitored for a period of 150 days of curing. The testing and monitoring programmes are conducted in undrained conditions, with and without pressure application. The obtained results show that the curing stress affects the hydro-mechanical behaviour of CPB for up to 28 days. Within this curing period, the CPB exhibits enhanced hydro-mechanical performance. However, application of sustained excessive curing stress onto the CPB samples induces the propagation of microcracks in the backfill structure, thus causing lower mechanical strength and higher fluid permeability at the more advanced ages. Furthermore, the mineralogical and chemical compositions of the tailings (e.g., sulfidic tailings) can significantly alter the mechanical strength properties (uniaxial compressive strength and elastic modulus) and the permeability of the CPB. The evolution of coupled factors and characteristics of the CPB at an early age control and influence its long-term behaviour and performance.     

高密度电法勘探数据在Voxler平台的三维可视化展示——及其在尾矿库隐患勘查中的应用

尾矿库内堆放的有污染的固体和液体废物若得不到合理妥善的处理,会对周边的环境造成严重的污染.为了确定尾矿库的稳定性,分析尾矿库内的固、液废弃物对周边土壤和地下水的影响,急需查明尾矿库的形态特征和库容规模.高密度电法作为一种常规的物探方法,以其简便、快捷、高效等特点,在确定尾矿库形态特征方面成为现场探测的首选技术手段.本研究运用高密度电法反演得到尾矿库的底界面范围,并结合钻孔验证,在Voxler平台构建了尾矿库的可视化三维模型,从而更加精确计算尾矿砂的方量,证明了高密度电法在确定尾矿库形态特征中的可行性.