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951.
针对大峪口磷石膏尾矿坝的实际情况,设定多种运行工况。运用饱和-非饱和渗流理论,分析磷石膏尾矿坝在各种工况下的渗流场。渗流场分析结果表明,干滩长度变化以及排渗垫层的淤堵程度对浸润线的影响十分明显,干滩长度越长,坝体浸润线越低;排渗垫层淤堵越重,浸润线越高。在渗流场分析的基础上,运用饱和-非饱和边坡稳定性分析方法,对坝体进行稳定性分析,得出不同工况下坝坡的安全系数。坝坡稳定性分析结果表明,在当前实际运行坝高180m时,最小安全系数为2.27,坝体是稳定的。不同工况下的安全系数均满足技术规程的规定。 相似文献
952.
《Urban Water Journal》2013,10(1):33-37
The removal of heavy metals from storm and surface waters by slow sand filtration is described. The importance of speciation as a technique for exploring and improving the mechanisms of removal is identified. Laboratory-scale slow sand filters operating at conventional flow rate and depth were shown to be able to reduce concentrations of selected heavy metals (Cu, Cr, Pb and Cd) found in road runoff, surface water and sewage effluents to drinking water standard. Nitrogen, volatile solids and modified Stover speciation were used to differentiate between the potential mechanisms of removal, i.e. active biomass, organic adsorption and simple adsorption or precipitation on the surface of the sand. The data presented show that adsorption via organic ligands was the predominant mechanism for metal removal at the surface of the filter but chemical adsorption was the more important deeper in the filter. In the lower layers the adsorbed metals were more easily exchanged than the organically bound metals. The precise chemical ligands were not identified and varied from metal to metal. The most important operational factors affecting performance were therefore the concentration of organic matter, filter depth and the flow velocity. 相似文献
953.
砂浆脱落是最常见的房屋质量通病,而其成因却常常难以追溯。该文结合工程实例介绍了一种房屋抹灰砂浆大面积脱落调查分析方法,包括设计与施工资料调查、现场检测和抽样分析,可为今后类似问题的处理提供技术参考。 相似文献
954.
955.
This contribution provides insight on the elimination of heavy metals from water resources using magnetic separation. Nanocomposites based on magnetite and chitosan were prepared. An exhaustive characterization of the magnetic adsorbents was developed. Adsorption assays were performed in batch using Cu, Zn, Cd, and Cr as model heavy metals. The efficiency of magnetic adsorbents followed the order: Cu > Cd > Zn > Cr, with maximum values of 188, 159, 72, and 46 mg of Me/g of nanocomposite, respectively. Kinetics and mechanistic issues were studied. The magnetic materials were efficient for five to eight cycles using Cu(II),Cd(II), and Cr(VI). 相似文献
956.
The aim of this study was to investigate the possibility of producing sinter/pellet grade concentrate from iron ore tails. Two different wet flow sheets were considered. The first consists of a teetered bed separator (TBS) followed by a gravity concentration resulting in a product quality with 65.54% Fe, 4.96% SiO2 and 1.50% Al2O3 content ensuring 68.52% iron recovery. In the second option, the iron ore tail is treated in a similar approach, but the gravity concentration replaced by magnetic separation results in a product quality with 65.34% Fe, 3.70% SiO2 and 1.00% Al2O3 with 70.91% of iron recovery. 相似文献
957.
《Ceramics International》2016,42(14):15383-15396
This study examines the effects of replacing fluxing and filler materials with rice straw ash (RSA) in manufacturing porcelain stoneware tile, using the design of experiments (DOE) methodology. The results of the characterization were used to obtain statistically significant, valid regression equations, relating the technological properties of the dried and fired test pieces to the raw materials content in the unfired mixtures. The regression models were analysed in relation to the X-ray diffraction and scanning electron microscopy results and used to determine the most appropriate combinations of traditional raw materials and RSA to produce porcelain stoneware tiles with specific technological properties. The studied range of tile body compositions: clay (40 wt%), feldspar (20–50 wt%), feldspathic sand (5–20 wt%), and RSA (0–25 wt%) was shown to be appropriate for porcelain stoneware tile manufacture. 相似文献
958.
959.
Fe‐substituted Ba‐hexaaluminates oxygen carrier for carbon dioxide capture by chemical looping combustion of methane 下载免费PDF全文
Ming Tian Xiaodong Wang Xin Liu Aiqin Wang Tao Zhang 《American Institute of Chemical Engineers》2016,62(3):792-801
Fe‐substituted Ba‐hexaaluninates (BFA‐x (x = 1–3), x indicates Fe content) oxygen carrier (OC) were found to exhibit excellent sintering‐resistance under cyclic redox atmosphere at 800°C thanks to the reservations of the structure during the CH4 reduction step, thus preventing the agglomeration of particles during the subsequent reoxidation step. Lattice oxygen highly active for the total combustion of CH4 was observed in the hexaaluminate structure and its chemical state was influenced by Fe content. The highest amount of active O coordinated with Fe3+ in the mirror plane (O‐Fe3+(M)) for the total combustion was reacted (0.77 mmol/g) for BaFe3Al9O19 hexaaluminate OC. As a result, it exhibited the best reactivity with the CH4 conversion of 83% and CO2 selectivity of 100%. Moreover, superior regeneration and recyclability was also obtained, which originated from the fully recovery of O‐Fe3+(M) in the hexaaluminate structure. © 2015 American Institute of Chemical Engineers AIChE J, 62: 792–801, 2016 相似文献
960.
针对污水处理厂进水受工业废水影响导致COD_(Cr)难去除的问题,通过现场中试,提出增加活性砂过滤-臭氧接触氧化的深度处理工艺,可将出水水质由GB 18918—2002《城镇污水处理厂污染物排放标准》一级B标准提高到一级A标准。重点介绍了升级改造工程方案设计,给出了设计参数及投资运行成本。 相似文献