共查询到16条相似文献，搜索用时 984 毫秒
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堆浸生产中,高锑金矿样品采用氢醌容量法测金,锑对测定有严重的正干扰,采用氯化铵培烧除锑或溴化氢挥发除锑,可消除锑对金的干扰,该方法快速、简单,效果明显。 相似文献
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酒石酸络合掩蔽锑-氢醌容量法测定锑矿石样品中的常量金 总被引：1，自引：1，他引：0
应用王水溶样-活性炭富集金-氢醌容量法测定高品位锑矿石的金量时,通常受到较高含量的锑硫砷汞等元素的干扰,硫砷汞碳及有机质可以通过阶梯升温焙烧去除,但是对锑则无明显去除作用。本研究在相关实验环节通过加入酒石酸使锑的干扰问题得到解决,包括:王水溶矿时加入酒石酸络合锑,防止锑的化合物在酸度或温度降低时水解,保证吸附金的活性炭灰化后的锑量小于0.3 mg;活性炭灰化除碳后,用王水溶解金时再加入酒石酸,消除了氢醌容量法滴定过程中少量锑的干扰。本方法只需在溶矿时加入一定量酒石酸,与氢溴酸除锑、盐酸等除锑方法相比具有原理简明、测试快速等特点,用于分析实际锑矿石的精密度(RSD)小于5%,加标回收率为92.0%~107.0%。 相似文献
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堆浸生产中高锑样品金的测定 总被引：2，自引：0，他引：2
在堆浸提金生产中，应用高锑样品的湿法测金方法，用氯化铵和溴化氢挥发法除去锑对金测定的干扰，用氢醌容量法测定，快速、简单、效果明显。 相似文献
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水中氯离子的测定过去通常采用铬酸钾指示剂容量法,或硝酸汞容量法;煤中氯的测定多采用艾氏剂或高温燃烧法。上述方法主要缺点是操作繁琐和滴定终点不好掌握,容易带来误差。由于氯离子选择电极本身具有抗干扰性强、灵敏度高和不受测试液色泽、浑度的影响等特点,故可应用它测定氯的含量。本文在前人工作基础上,进行了条件实验,确定了天然水及煤中氯的电极法测定方法。本法干扰少、精度高、成批生产快速、能满足生产需要。 相似文献
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硅氟化钾容量法测定岩石和矿物中二氧化硅比重量法简单快速。但该法问世半个多世纪以来,虽经国内外分析工作者不断改进,但结果不稳的问题仍未得到很好解决。对造成结果不稳的原因及测试的最佳条件,各文献报道很不一致,对一些问题有不同见解。所以如何进一步解决方法稳定性问题,还值得我们进一步探索。 相似文献
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在容量法对页岩的等温吸附实验测试中,发现随压力增加吸附量呈现减小趋势,甚至出现负吸附量,测得的吸附常数Langmuir体积和Langmuir压力出现负值,与实际不相符,造成实验结果和吸附常数失去应用价值。从页岩吸附测试方法、吸附测试仪器等方面系统分析了容量法页岩吸附实验出现"倒吸"现象的原因;提出了实验中自由空间体积测试和吸附气含量计算存在的问题;并对页岩吸附实验方法和页岩吸附测试仪器提出相关建议。 相似文献
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对氢化物发生-原子荧光法同时测定水中砷、硒含量的条件进行探讨,并通过实例进行验证。通过对不同仪器测试条件和试剂用量的分析,选择最优测试条件进行测试,测定线性关系0.999,砷、硒检出限低,分别为0.052和0.073μg/L,满足检测应用要求;并且通过国家标准样品测试和地下水样品加标实验进行验证,标准样品测试结果与加标回收率均合格,方法的准确度及精密度结果满意。该实验方法操作简单、快速,适用于地下水中砷、硒的同时测定。 相似文献
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氢醌滴定法测定金矿石中金的不确定度评定 总被引：5，自引：4，他引：5
以氢醌滴定法测定金矿石中贵金属金的实例进行不确定度评定。测量结果的不确定度由配制金标准母液、金标准工作液、氢醌滴定液浓度、称样质量、滴定样品所用氢醌溶液体积等所引入的不确定度分量组成。在对各个不确定度分量进行量化的基础上，通过合成得到测量结果的标准不确定度，再乘以95％置信概率下的扩展因子2，得到测量结果的扩展不确定度。 相似文献
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含锑地质试样中金的测定 总被引：3，自引：1，他引：3
本文考查了Sb对氢醌法测Au的影响。实验证明,Sb的存在使Au的结果偏高,酒石酸钾钠只掩蔽2mg的Sb。对于含Sb试样,灼烧除Sb并不完全,即使经活性炭吸附Au处理后的待测样中Sb仍存在。本文采用HBr辅助除Sb取得良好效果。方法简便、准确性好,Au的回收率在95.5—102.75％范围,试样测定结果与其它方法相符。 相似文献
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氧化铁矿物催化分解苯酚的动力学速率及其产物特征 总被引：3，自引：0，他引：3
本文研究了针铁矿、纤铁矿、赤铁矿和磁铁矿在过氧化氢参与下催化分解苯酚的动力学速率与溶液pH值的关系,并用紫外吸收谱测定了反应产物的谱学特征。结果表明,纤铁矿反应体系催化分解苯酚的速率常数(k)最大,其余依次为磁铁矿、针铁矿和赤铁矿。在纤铁矿反应体系中又以pH=3.8时反应速率常数最大。除赤铁矿反应体系外,当溶液pH=3~4时苯酚被完全分解,并有50%~65%的有机碳(TOC)被矿化。在pH=3.25的赤铁矿反应体系中,苯酚大多仅被转化为多酚,小部分苯环被打开形成己烯酸。当溶液pH=4~5时,苯酚一般仅被转化为多酚类化合物,但TOC基本不变。当溶液pH>5时,苯酚没有发生明显的转化和矿化现象。 相似文献
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Reduction of crystalline iron(III) oxyhydroxides using hydroquinone: Influence of phase and particle size 总被引：1，自引：0，他引：1
Iron oxides and oxyhydroxides are common and important materials in the environment, and they strongly impact the biogeochemical
cycle of iron and other species at the Earth's surface. These materials commonly occur as nanoparticles in the 3–10 nm size
range. This paper presents quantitative results demonstrating that iron oxide reactivity is particle size dependent. The rate
and extent of the reductive dissolution of iron oxyhydroxide nanoparticles by hydroquinone in batch experiments were measured
as a function of particle identity, particle loading, and hydroquinone concentration. Rates were normalized to surface areas
determined by both transmission electron microscopy and Braunauer-Emmett-Teller surface. Results show that surface-area-normalized
rates of reductive dissolution are fastest (by as much as 100 times) in experiments using six-line ferrihydrite versus goethite.
Furthermore, the surface-area-normalized rates for 4 nm ferrihydrite nanoparticles are up to 20 times faster than the rates
for 6 nm ferrihydrite nanoparticles, and the surface-area-normalized rates for 5 × 64 nm goethite nanoparticles are up to
two times faster than the rates for 22 × 367 nm goethite nanoparticles. 相似文献
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J.A. Tossell 《Geochimica et cosmochimica acta》2009,73(7):2023-2033
Humic substances present a geochemically and environmentally important, yet poorly characterized, component of dissolved organic matter. In the past they have generally been described as macromolecular polymers containing many different functional groups. Recently, it has been suggested, partly on the basis of new experimental data, that such materials are rather supramolecular in nature, consisting of smaller molecular units held together by noncovalent forces such as van der Waals forces and H-bonds. A perplexing difficulty in characterizing humic acids has always been that data expected to be informative, such as their Visible-UV spectra, were sadly lacking in structure. This has usually been explained using models in which ensembles of molecules are present characterized by either long-range charge-charge interactions or random short-range donor-acceptor interactions.Structural components resembling hydroquinone:quinone donor-acceptor complexes have been postulated to explain the near-IR and visible spectra of humic acids (Del Vecchio R., and Blough N.V. (2004) On the origin of the optical properties of humic substances. Environ. Sci. 38, 3885-3891). We have calculated structures, energetics and Visible-UV spectra for several different quinone and hydroquinone monomers and for donor-acceptor complexes formed between hydroquinone, H2Q, the donor, and quinone, Q, the acceptor. Most of the Visible-UV spectral calculations are carried out using time-dependent density functional theory. For the monomers the calculated energies are in good agreement with experiment. We confirm that the absorption spectra of the D:A complexes have maxima at much lower energy than their monomeric components. These absorption energies are influenced by substituents on the aromatic rings, but are also sensitive functions of the distances between the aromatic rings. The importance of D:A complexes in generating a spectrum like that of natural humic acids is consistent with the model of Del Vecchio and Blough (2004). However, our calculations of reaction free energies indicate that the donor-acceptor interactions do not arise from free D:A complexes, but rather from forced or random close approach of D and A rings. 相似文献