Magnesium recovery from magnesite tailings by acid leaching and production of magnesium chloride hexahydrate from leaching solution by evaporation

The recovery of magnesium from magnesite tailings in aqueous hydrochloric acid solutions by acid leaching was studied in a batch reactor using hydrochloric acid solutions. Subsequent, production of magnesium chloride hexahydrate (MgCl₂.6H₂O) from leaching solution was also investigated. The effects of temperature, acid concentration, solid-to-liquid ratio, particle size and stirring speed on the leaching process were investigated. The pseudo-second-order reaction model seemed to be appropriate for the magnesium leaching. The activation energy of the leaching process was estimated to be 62.4 kJ mol^− 1. Finally, MgCl₂.6H₂O in a purity of 91% was produced by evaporation of leaching solution obtained at a temperature of 40 °C, 1.0 M acid, solid-to-liquid ratio of 10 g/L, particle size of 100 µm, stirring speed of 1250 rpm and leaching time of 60 min.     

地震作用下高堆尾矿坝永久变形与稳定性分析

综合采用时程分析法、整体变形分析法（等效节点力法和软化模量法）、极限平衡法等方法,以小打鹅尾矿库为例,分析了该高堆尾矿坝的永久变形和动力稳定性。分析了干滩面长度、尾矿堆积坝高度、设计地震加速度等影响因素对尾矿坝的安全系数和永久变形的影响,以及地震作用下尾矿坝安全系数的时程变化规律。结果表明：尾矿坝的地震永久变形与一般土石坝的存在差异,其水平方向的永久变形大于竖直方向的永久变形,且永久变形与坝高不一定呈单调递增关系;地震中尾矿坝的最小安全系数与各影响因素大体呈线性关系,而坝顶处的震陷与各影响因素之间呈非线性关系;地震过程中尾矿坝瞬时安全系数具有波动降低的特点,为此,完善了地震作用下尾矿坝最小平均安全系数的计算方法。该研究表明小打鹅尾矿库坝体的抗震性能能够满足相应抗震设防要求。     

金川镍矿尾矿砂中Ni和Cu赋存状态研究

金川镍矿浮选尾矿数量巨大,含有相当可观的有价金属,其中有价金属的回收受到越来越多的关注。金川老尾矿库尾矿砂中Ni和Cu赋存状态复杂,水溶性矿物态、可交换离子态、碳酸盐态、结晶度较差的Fe氧化物态、结晶度较好的Fe氧化物态、硫化物态和残渣态中都含有数量不等的有价金属Ni和Cu;尾矿砂风化作用释放的金属阳离子大多数在发生氧化的硫化物位置原位发生水解沉淀形成次生矿物,有价金属Ni和Cu在尾矿库中没有发生明显的富集。金川镍矿尾矿砂中Ni和Cu适于用化学酸溶浸出的方法进行二次回收。     

Geotechnogenesis problems

Geotechgjgensis is mineralogical geochemical transformation of minerals, rocks, and ores as consequence of impact on them in the process of performing geological-exploration and irrigation works, extracting and processing mineral resources, constructing transport, civil and military objects. These effects lead to discontinuity and moving different scale fragments ofuppor part of lithospere and conjugate hydro-and biosphere zones. Discontinuity predttermines the disturbance of matural systems dynamic equilibriu and acceleration of mftter transformation and migration processes. The final aim of studying geotechnogenesis minseralogy and geochemistry is the establishment of scientific foundations for developing ecological safety measures including also utilization fo geotechnogene deposits.     

兰陵县王埝沟铁矿矿山固体废弃物对环境的影响分析及综合利用探讨

王埝沟铁矿床为我国已探明的大型铁矿床,正处于开采初期阶段,年产铁精矿71.33万t,服务年限37.5a。矿山运营期间产生了废石、尾砂、锅炉灰渣等大量的固体废弃物。该文通过对废石、尾矿的伽玛能谱测量分析认为:废石和尾砂的放射性含量较低,开采、选冶过程及固体废弃物的综合利用,不会对人体及环境造成放射性危害。通过对废石、尾矿以及锅炉灰渣毒性浸出实验结果的分析研究,认为废石、尾矿为第Ⅰ类一般工业固体废物,其淋溶水不会导致地下水水质恶化及土壤的污染;锅炉灰渣属于第Ⅱ类一般工业固体废物,其存储场应按照Ⅱ类场要求执行,其淋溶水也不会导致地下水水质恶化及土壤的污染。该文对主要固体废弃物(废石和尾砂)的岩性组成、主要矿物特征和用途进行分析研究,参考以往矿山利用成果,提出了综合回收利用的具体方向,如用于建筑材料、路基填料、玻璃生产原料、研磨材料、陶瓷原料、水泥、石灰生产原料、土壤改良剂或肥料、化工原料等。     

某锡多金属选矿废水污染特征及防治措施

根据某锡多金属选矿厂的十多年选矿废水及尾矿库溢流水污染特性,分析研究尾矿库溢流水防治措施,为科学有效处理同类型的选矿废水及尾矿库溢流水提供参考。     

The effect of Ca–Fe–As coatings on microbial leaching of metals in arsenic bearing mine waste

Globally arsenic (As) is a ubiquitous trace element derived from the natural weathering of As-bearing rock. With the onset of reducing conditions, the prevalence of aqueous As(III) may be intensified through biotic and abiotic processes. Here we evaluate the stability of arsenic bearing Ca–Fe hydroxide phases collected from exposed tailings at Ketza River mine, Yukon, Canada, during the reductive dissolution of both acid treated and untreated samples by Shewanella putrefaciens 200R and Shewanella sp. ANA-3. Samples were acid treated in order to remove Ca–Fe oxide coatings and evaluate the influence of these coatings on the rates of microbial Fe(III) and As(V) reduction. Environmental scanning electron microscope (ESEM) micrographs of the solid phase show significant differences in the chemistry and physical morphology of the material by the bacteria over time and are especially evident in the acid treated samples. Moreover, while solution chemistry showed similar As(III) respiration rates of the inoculated acid treated samples for both ANA3 and 200R at ~ 1.1 × 10⁻⁶ μM·s^− 1·m^− 2, the Fe(II) respiration rates differed at 1.4 × 10^− 7 and 9.5 × 10^− 8 μM·s^− 1·m⁻² respectively, thus suggesting strain specific metal reduction metabolic pathways Additionally, the enhanced metal reduction observed in the acid treated inoculated samples suggests that the presence of the Ca–Fe hydroxide phase in the untreated samples acted as a barrier, inhibiting the bacteria from accessing the metals. This has implications for increased mobilization of metals by metal reducing bacteria within areas of increased acidity, such as acid mine drainage sites and industrial tailings ponds that can come into contact with surface and ground water sources.     

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、J622;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。     

Toxic metal contamination in the lateral lakes of the Coeur d'Alene River valley, Idaho

 The 11 lateral lakes of Coeur d'Alene River valley in northern Idaho have received heavy metal contamination from over a century of upstream mining. The lateral lakes lie within the flood plain of the Coeur d'Alene River, and in their bottom sediments is preserved a stratigraphic record of the upstream mining operations. To characterize the contaminated sediments in the lateral lakes, sampling techniques, including the Livingston piston corer and the Huttenen freeze box, have been developed by Quaternary geologists to preserve the vertical stratigraphy in the samples. From 26 cm to over 55 cm of undisturbed tailing sediments, commonly with “varve-like” features, have been found in each of the lateral lakes, with maximum concentrations by weight of lead at 3.8%, zinc at 3.4%, arsenic at 340 mg/kg, cadmium at 120 mg/kg and mercury at 7 mg/kg. The contamination in the lakes appears to be restricted to the shallow subsurface and heavy metal concentrations generally drop to background levels within a meter of depth. Received: 22 May 1998 · Accepted: 21 September 1998