石墨炉原子吸收法测定钛铁矿中的微量镉

研究了石墨炉原子吸收测定钛铁矿中微量元素 Cd 的方法,探索了在高含量的 Fe,Ti 基体干扰下以NH4H2PO4-H2NCSNH2-EDTA为混合基体改进剂的最佳仪器工作条件。在取样0．2000g,定容25 mL的条件下,方法检出限为0．006μg/g,用国家标准物质验证,其准确度（犚犈％）＜10％,12次测定精密度（犚犛犇％）＜10％,加标回收率90％～110％之间,符合国家相关要求。     

河南省内乡县午阳山矿区石墨矿矿床地质特征及成因

内乡县午阳山矿区石墨矿属于蛇尾-小岔沟与元古宙变质海相碳酸盐岩、含炭碎屑岩有关的石墨矿床成矿亚系列,属于沉积变成矿床。矿区内出露地层主要为古元古界秦岭群雁岭沟组和石槽沟组,石墨矿体分布于雁岭沟组二段内部,矿区内褶皱构造发育并影响区内主要矿体分布。     

高钛型高炉渣与硫酸铵焙烧过程中反应产物的变化与形成机理研究

高钛型高炉渣富含TiO₂,是一种重要的矿物资源。为实现其中TiO₂的富集,研究了其与硫酸铵的混合物在焙烧过程中反应产物的变化及形成机理。采用TG-DTA和XRD对高钛型高炉渣与硫酸铵混合物的热效应变化和原料及焙烧产物的物相组成进行了表征。结果表明,高钛型高炉渣主要矿物组成为钙钛矿、透辉石和镁铝尖晶石,其与硫酸铵的混合物在加热过程中存在3个明显的吸热效应,为硫酸铵自身分解反应及与高钛型高炉渣中金属氧化物的反应和所形成的中间产物的分解反应所引起。在较低的焙烧温度下,硫酸铵分解产物为(NH₄)₃H(SO₄)₂,其与钙钛矿和透辉石中的金属氧化物反应可形成CaSO₄;在焙烧温度为300～375℃时,镁铝尖晶石中的Al₂O₃与(NH₄)₂SO₄和(NH₄)₃H(SO₄)₂反应形成(NH₄)₃Al(SO₄)₃;在375～425℃时,(NH₄)₃Al(SO₄)₃与Al₂O₃反应形成NH₄Al(SO₄)₂;焙烧温度升高至500℃时,NH₄Al(SO₄)₂发生分解生成Al₂(SO₄)₃。     

Detoxification of hazardous dust with marine sediment

Hazardous electric arc furnace dust containing dioxins/furans and heavy metals is blended with harbor sediment, fired at 950–1100 °C to prepare lightweight aggregates. Dust addition can lower the sintering temperature by about 100 °C, as compared to a typical industrial process. After firing at 950 °C and 1050 °C, more than 99.85% of dioxins/furans originally present in the dust have been removed and/or destructed in the mix containing a dust/sediment ratio of 50:100. The heavy metals leached from all fired mixes are far below Taiwan EPA legal limits. The particle density of the lightweight aggregates always decreases with increasing firing temperature. Greater addition of the dust results in a considerably lower particle density (mostly <2.0 g cm⁻³) fired at 1050 °C and 1100 °C. However, firing at temperatures lower than 1050 °C produces no successful bloating, leading to a denser particle density (>2.0 g cm⁻³) that is typical of bricks.     

Archaeometric characterisation and origin of black coatings on prehistoric pottery

Black or dark grey vessel surfaces with characteristic metallic lustre are recognised from various archaeological contexts throughout Europe. This feature is commonly attributed to the application of graphite-bearing coatings onto ceramic vessels. However, recent experimental studies have shown that a very similar visual effect can alternatively be achieved by polishing and, subsequently, firing in a reducing atmosphere (so-called smudging). In this study, experimentally manufactured ceramics as well as samples of prehistoric ware (dated to the Neolithic Age, late Bronze Age and early Iron Age) have been analysed to find the distinguishing features between graphite-based and non-mineral black coatings. In the low-magnification BSE images the well-preserved graphite-coated surfaces are characterized by a distinctive spotty pattern with numerous dark grey angular fragments of monomineralic or nearly monomineralic metamorphic rocks scattered in the clay groundmass. Provided that polished thin sections are skilfully prepared, individual graphite plates can be easily recognized in the near-surface layer of the sherds using polarized reflected light microscopy. A relatively homogeneous appearance is typical of the low-magnification BSE images of surfaces coated by smudging. At higher magnifications, presence of blurred darkish stains (presumably organic-derived, as indicated by elevated levels of biogenic elements) is characteristic of this kind of non-mineral black coatings. SEM-EDS and optical microscopy have been supplemented by micro-Raman spectroscopy, which allows differentiation between various carbonaceous phases.     

Correlation between optical, chemical and micro-structural parameters of high-rank coals and graphite

In order to identify the parameters that best characterize the chemical and structural evolution of organic matter during coalification, the relationships between optical, chemical and micro-structural parameters in high-rank coals and natural graphite were studied. The samples include anthracites from Peñarroya–Belmez–Espiel Basin (Spain), Douro Basin (Portugal), and Alto Chicama Basin (Peru); and natural graphite from Canada, Mozambique, and Austria.Correlations between the following optical parameters were assessed: vitrinite random reflectance (R_r), Reflectance Indicating Surfaces (RIS) axis (R_MAX, R_INT and R_MIN), and RIS parameters (R_am, R_ev and R_st), as well as B_w and AI anisotropy parameters. Furthermore, the chemical parameters used were chosen according to their significant variation in coals, namely volatile matter, carbon, and hydrogen contents calculated in dry ash free basis (VM_daf, C_daf, H_daf), as well as the H/C atomic ratio. Structural organization was characterized by micro-Raman spectroscopy and XRD. Raman parameters used were the full width at half maximum (FWHM) and position of G and D1 bands on the first-order Raman spectrum, and the ID1/IG intensity area ratio. The selected XRD parameters were interlayer spacing d₀₀₂, and crystallite sizes L_a and L_c.Results show that: (i) R_MAX RIS axis seems to correlate best with chemical and micro-structural parameters; (ii) for the majority of studied samples, H_daf and H/C atomic ratio are the only chemical parameters with significant correlations with R_MAX; (iii) the FWHM of the G band of Raman spectrum shows good linear correlation with the XRD parameter d₀₀₂; and, (iv) structural organization of carbon materials, as measured by trends in their optical and crystalline parameters, is influenced by their hydrogen content (daf basis) and therefore by the H/C atomic ratio.     

具有逆辨识结构的模糊神经网络控制及其应用

该文提出一种新型模糊神经网络结构及算法。在这种控制方案中,采用三层模糊神经网络控制器和神经网络逆辨识控制器相结合的结构。计算机仿真研究和实际应用表明,采用新型模糊神经网络控制方法,对大滞后非线性系统的控制是有效的。     

电炉炼钢烟气特点及捕集净化措施

通过介绍电炉烟气的特点并对目前国内外所采取的各种电炉烟气捕集净化措施进行描述和分析,提出了适合我国国情的电炉烟气捕集形式,并就电炉烟气的净化提出了解决二英等污染物的治理对策。     

微波消解-石墨炉原子吸收光谱法测定痕量银的研究

传统的应用石墨炉原子吸收光谱法测定化探样品中的痕量银,一般采用盐酸-硝酸-氢氟酸-高氯酸电热板加热溶样,使用铱、铂为基体改进剂,但存在分析流程繁琐、成本高等缺点。相比于电热板消解法,微波消解技术的高压密闭消解和微波快速加热等特点,具有酸用量少、消解完全、消解过程损失少等优点。本文对传统的微波消解和仪器工作参数进行了改良,确定了最佳测定条件。建立了HNO_3-H_2O_2高压密闭消解样品,石墨炉原子吸收法测定水系沉积物、土壤、岩石中痕量银的方法。采用65%的HNO_3和H_2O_2微波消解溶样,加入12 g/L硫脲为介质,消除了基体干扰。方法检出限为0.018μg/g,将所建立的分析方法用于沉积物标准物质(GBW07309、GBW07311)、土壤标准物质(GBW07402、GBW07404)和岩石标准物质(GBW07103、GBW07104)验证,结果显示测定值与推荐值吻合,准确度△lg C(GBW)≤±0.024、RE(GBW)≤±5.71%,精密度RSD(GBW)≤5.97%。该分析方法适用于大批化探样品中痕量银的测定。     

http://www.sciencedirect.com/science/article/pii/S1674987111001083

Stable carbon isotope geochemistry provides important information for the recognition of fundamental isotope exchange processes related to the movement of carbon in the lithosphere and permits the elaboration of models for the global carbon cycle.Carbon isotope ratios in fluid-deposited graphite are powerful tools for unravelling the ultimate origin of carbon（organic matter,mantle,or carbonates） and help to constrain the fluid history and the mechanisms involved in graphite deposition.Graphite precipitation in fluid-deposited occurrences results from CO₂- and/or CH₄-bearing aqueous fluids.Fluid flow can be considered as both a closed（without replenishment of the fluid） or an open system（with renewal of the fluid by successive fluid batches）.In closed systems,carbon isotope systematics in graphite is mainly governed by Rayleigh precipitation and/or by changes in temperature affecting the fractionation factor between fluid and graphite.Such processes result in zoned graphite crystals or in successive graphite generations showing,in both cases, isotopic variation towards progressive ^l3C or ¹²C enrichment（depending upon the dominant carbon phase in the fluid.CO₂ or CH₄,respectively）.In open systems,in which carbon is episodically introduced along the fracture systems,the carbon systematics is more complex and individual graphite crystals may display oscillatory zoning because of Rayleigh precipitation or heterogeneous variations of 5’ C values when mixing of fluids or changes in the composition of the fluids are the mechanisms responsible for graphite precipitation.