排序方式： 共有76条查询结果，搜索用时 15 毫秒
1.
《International Journal of Mineral Processing》2005,76(3):143-147
Spent hydro-refining catalysts mainly consists of 20–22% MoO3, 5–6% NiO, 4–5% S, 1–2% Co3O4, 1.3–1.5% Fe2O3, 3–4% SiO2, and the balance is Al2O3. In the present study, one such spent catalyst was roasted with sodium chloride to recover molybdenum by converting it into sodium molybdate. The sodium molybdate was further purified by chemical treatment to obtain a pure grade molybdenum trioxide. Various parameters like temperature, time and NaCl addition have been studied, and conditions for the maximum recovery of molybdenum have been established. 相似文献
2.
《Applied Geochemistry》2005,20(1):123-133
The use of the organoarsenical roxarsone, added to poultry feed to increase weight gain, results in elevated As concentrations (10–50 mg/kg) in poultry litter. This litter is used extensively as fertilizer in agricultural regions. The authors investigated the sources and sinks of As within the vadose zone of an agricultural watershed in the Shenandoah Valley of Virginia, USA, an area of intense poultry production. Batch experiments were constructed to examine adsorption and biotransformation characteristics of roxarsone within the Ap and Bt soil horizons of Frederick series soils, common in the Shenandoah Valley. Roxarsone exhibits weak adsorption to the Ap soils; however, it is rapidly biotransformed to As(V) in this soil horizon. Although the Bt horizon demonstrated strong adsorption of roxarsone and thus may act as a sink for As species, soil water data collected from lysimeters at an agricultural field site suggest that As, as As(V), is mobile in the Bt soil water. It is unclear if this mobilization is due to competitive reactions with phosphate or organic acids, also present in litter. These results have implications for As cycling within poultry-dominated watersheds. For watersheds that have experienced years of litter application, As and other litter-associated species will be attenuated in soils through adsorption to mineral surfaces, but a variety of geochemical processes, such as competitive adsorption, may allow for enhanced transport of As through the vadose zone and into aquifer systems. 相似文献
3.
4.
??????????????????????????????????????????L??1??-?????????????????????????????????????????????????????????M??????÷???????н?????????????????С??????????????????????÷??????????????????LS????????????￡?????Ч???????????????????????????????????????? 相似文献
5.
小秦岭地区太华群锆石U-Pb年龄及华北克拉通南缘地壳演化 总被引：4，自引：0，他引：4
以小秦岭地区太华群二长片麻岩为研究对象,分析其地球化学、锆石U-Pb年龄和Hf同位素特征。地球化学分析显示其原岩为高钾钙碱性花岗质岩石,稀土元素总含量较高(229×10-6),轻、重稀土元素分馏明显(w(La)N/w(Yb)N=45.39),有明显的Eu负异常(0.43)。原始地幔标准化微量元素蛛网图显示其富集Rb、Ba、Th、U等大离子亲石元素和亏损Nb、Ta、Sr、P、Ti等高场强元素。锆石U-Pb定年结果显示,其原岩的形成时代为古元古代早期(2.47Ga)。锆石Hf同位素分析结果显示:初始N(176 Hf)/N(177 Hf)值变化范围很小,为0.281 284~0.281 328,εHf(t)值均为正值(0.93~5.18);二阶段Hf模式年龄为2.70~2.89Ga,新生地壳(现代岛弧火山)Hf模式年龄为2.54~2.73Ga,接近于锆石结晶年龄(2.47Ga),指示华北克拉通南缘在这一时期有明显的新生地壳生长。华北克拉通南缘在新太古代早期(2.7~2.9Ga)、新太古代晚期—古元古代早期(2.2~2.5Ga)和古元古代中期(1.8~2.1Ga)有3期重要的构造热事件。新太古代早期及晚期有明显的新生地壳生长(εHf(t)0),新太古代晚期—古元古代早期和古元古代中期的岩浆活动有明显的新生地壳生长,同时还伴随有古老地壳物质的再循环和改造(εHf(t)0或εHf(t)0)。 相似文献
6.
???????????????????IPSO??????????????????????м??????????????????????????????????????????????????????????????????????????????BP?????????γ?IPSO_BP??????????????????μ????????????????????????IPSO_BP???????????????Ч?????????????????????????????? 相似文献
7.
8.
广西大厂锡多金属矿田西矿带稀散元素铟的富集规律研究——来自矿石组构和闪锌矿地球化学的证据 总被引：7，自引：2，他引：5
广西大厂锡多金属矿田是世界最主要的铟产地之一,对其的富集机制还有很大争议。文章以大厂矿田西矿带高峰矿床和铜坑矿床中的闪锌矿为研究对象,在野外和室内矿相显微观察的基础上,应用高精度电子探针与等离子体质谱分析手段,研究稀散元素铟的空间分布规律、赋存状态及与主成矿元素的关系,揭示其在闪锌矿中的富集规律。实验结果表明,铜坑矿床中闪锌矿内稀散元素铟的含量随深度增加而减少,而高峰矿床中铟含量却保持稳定;铟主要以类质同象形式赋存,与铜以双替代锌的形式进入闪锌矿晶格中,也不排除铟以微细包体形式赋存的可能。结合前人研究,推断燕山晚期复式岩体岩浆演化末期花岗斑岩侵位冷却过程中,岩浆结晶产生的富铟、铜等流体对早期生成的闪锌矿进行交代并富集。这一研究结果为寻找稀散元素铟指示了方向。 相似文献
10.
基于双程波动方程的逆时偏移(RTM)具有原理简单、无倾角限制、具有可以适用于速度任意变化的模型,对各类波正确成像等优点,但采用互相关成像条件会产生严重的低频噪声问题。笔者分析低频噪声的产生机制后提供了一个有效的波场分离去噪方法,将震源和检波点波场分离成不同方向的单成波分量,只对有效路径上的分量进行互相关成像,从而达到去除噪声的目的。并通过模型测试对比了坡印廷矢量滤波、拉普拉斯滤波、波场分离滤波这三种方法的去噪效果,结果表明基于波场分离的去噪方法效果更好。 相似文献