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石煤提钒技术关键是钒的氧化和转化。浙川石煤中钒主要有V~(3+)和V~(4+)形式存在,以类质同象取代粘土矿物二八面体中Al~(3+)。钒的价态分布研究表明,低温时有机质和黄铁矿决定了钒的价态,在370℃(风化样)或490℃(原样)V~(3+)全部氧化至V~(4+);高于800℃V~(4+)不再氧化至V~(5+),反应处于动态平衡,此时ηV~(5+)达91％。同时讨论了氯化钠在提钒过程中的氧化和转化作用,石煤钠盐氧化焙烧提钒的最佳条件:矿:盐=100:15,800℃,30分钟,η_培为67.4％。实验表明,焙烧气氛对钒转化有很大影响,氧化—氯化焙烧技术提高η_培6％。 相似文献
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采用马弗炉将样品与NaOH混合进行熔融煅烧，热去离子水提取、离心、稀释后过OnGuard Ⅱ H柱和过滤膜进行前处理，抑制型电导离子色谱法检测，测定了Ta2O5和Nb2O5的氟离子、氯离子和硫酸根离子。该方法对三种被测阴离子的检测限（s／N=3）在0．15～0．70μg／g（以固体样品实际浓度计）或0．136～0．623μg／L（以溶液浓度计），标准曲线线性范围均在两个数量级以上，方法的精密度（RSD，n=7）小于5．46％，回收率为88％～106％，具有灵敏度高、选择性好、重现性佳、对环境友好等特点，用于实际样品的检测，结果令人满意。 相似文献
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余庆县小腮地区的钒矿赋存于下寒武统牛蹄塘组近底部,具有品位低、厚度大的特点,矿石类型属炭质泥岩型钒矿.钒在原矿中的价态主要以V^3＋形式存在,其次为V^4＋和V^5＋,其中V^3＋主要以类质同象形式取代Al^3＋、Fe^3＋等氧化矿物及硅酸盐矿物,而V^4＋、V^5＋则全部以吸附状态赋存于云母类矿物中.矿石通过“原矿—破碎—磨矿—浸出—固液分离—萃取—反萃—沉钒—脱铵—五氧化二钒成品”提钒工艺,其五氧化二钒浸出率达85％,五氧化二钒总回收率为79.20％,在环境保护上能得到较好的控制,所得产品质量达GB3283-87冶金用V20599牌号标准. 相似文献
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The Engineer Mine epithermal precious metal deposit in British Columbia, Canada, is related to Eocene Sloko-Skukum-Group (SSG) volcanism and, according to previous studies, contains roscoelite in intimate association with electrum. Roscoelite, a vanadian mica, is considered characteristic of low-sulfidation epithermal deposits related to alkaline magmatism. This contradicts the fact that the SSG volcanics are subalkaline. In order to address this ambiguity and to accurately classify the style of epithermal mineralization at the Engineer Mine we conducted detailed petrographic, mineralogical, geochronological, fluid inclusion, and stable isotope studies.The principal ore assemblage of the Engineer Mine epithermal veins precipitated in response to boiling during a hydrothermal event at 49.90 Ma ± 0.25 Ma. During this event electrum, arsenopyrite, pyrite ± chalcopyrite ± sphalerite ± löllingite ± tetrahedrite-group phases ± allargentum ± acanthite ± hessite ± dyscrasite ± stibarsen ± galena and an unidentified Ag-rich phase were deposited in conjunction with amorphous silica, platy and rhombic calcite, K-feldspar, and vanadian illite. Fluid inclusion and stable isotope data suggest that the ore-forming fluid was boiling at ∼220 °C during vein mineralization and had an isotopic composition derived from local meteoric water. Based on these results the Engineer Mine is classified as an epithermal low-sulfidation deposit, which shares similarities with alkaline and subalkaline epithermal low-sulfidation deposits. This is attributed to the fact that the SSG volcanic rocks are borderline subalkaline to alkaline in character and that the sedimentary host rocks are vanadium-bearing. These sedimentary rocks contributed the bulk of the vanadium to the Engineer Mine epithermal system. The presence of roscoelite at the Engineer Mine could not be confirmed during this study. The mica referred to as roscoelite in previous publications instead is vanadian illite. To our knowledge the only alkaline low-sulfidation epithermal precious metal deposit that contains V-mica which exclusively qualifies as true roscoelite is the Porgera deposit, Papua New Guinea. 相似文献
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《Geoforum》2017
Highly alkaline industrial residues (e.g., steel slag, bauxite processing residue (red mud) and ash from coal combustion) have been identified as stocks of potentially valuable metals. Technological change has created demand for metals, such as vanadium and certain rare earth elements, in electronics associated with renewable energy generation and storage. Current raw material and circular economy policy initiatives in the EU and industrial ecology research all promote resource recovery from residues, with research so far primarily from an environmental science perspective. This paper begins to address the deficit of research into the governance of resource recovery from a novel situation where re-use involves extraction of a component from a bulk residue that itself represents a risk to the environment. Taking a political industrial ecology approach, we briefly present emerging techniques for recovery and consider their regulatory implications in the light of potential environmental impacts. The paper draws on EU and UK regulatory framework for these residues along with semi-structured interviews with industry and regulatory bodies. A complex picture emerges of entwined ownerships and responsibilities for residues, with past practice and policy having a lasting impact on current possibilities for resource recovery. 相似文献
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The stoichiometry and kinetics of the reaction of NO2 with O3 at sub-ppm concentration level have been investigated as a function of temperature and relative humidity. The experiments were performed in a continuous flow reactor using chemiluminescent and wet chemical methods of analysis.The rate constant found can be described by the Arrhenius expression: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaiikaiaaik% dacaGGUaGaaGyoaiaaiEdacqGHXcqScaaIWaGaaiOlaiaaigdacaaI% 0aGaaiykaiabgEna0kaaigdacaaIWaWaaWbaaSqabeaacqGHsislca% aIXaGaaG4maaaakiaabwgacaqG4bGaaeiCaiaacIcadaWcgaqaaiaa% cIcacqGHsislcaaIYaGaaGOnaiaaikdacaaIWaGaeyySaeRaaGyoai% aaicdacaGGPaaabaGaamivaiaacMcacaqGGaGaae4yaiaab2gadaah% aaWcbeqaaiaabodaaaGccaqGGaWaaSGbaeaacaqGTbGaae4BaiaabY% gacaqGLbGaae4yaiaabwhacaqGSbGaaeyzamaaCaaaleqabaGaaeyl% aiaabgdaaaaakeaacaqGZbWaaWbaaSqabeaacaqGTaGaaeymaaaaaa% aaaaaa!62A3!\[(2.97 \pm 0.14) \times 10^{ - 13} {\text{exp}}({{( - 2620 \pm 90)} \mathord{\left/ {\vphantom {{( - 2620 \pm 90)} {T){\text{ cm}}^{\text{3}} {\text{ }}{{{\text{molecule}}^{{\text{ - 1}}} } \mathord{\left/ {\vphantom {{{\text{molecule}}^{{\text{ - 1}}} } {{\text{s}}^{{\text{ - 1}}} }}} \right. \kern-\nulldelimiterspace} {{\text{s}}^{{\text{ - 1}}} }}}}} \right. \kern-\nulldelimiterspace} {T){\text{ cm}}^{\text{3}} {\text{ }}{{{\text{molecule}}^{{\text{ - 1}}} } \mathord{\left/ {\vphantom {{{\text{molecule}}^{{\text{ - 1}}} } {{\text{s}}^{{\text{ - 1}}} }}} \right. \kern-\nulldelimiterspace} {{\text{s}}^{{\text{ - 1}}} }}}}\] and are independent of the relative humidity. As commonly encountered in previous studies a lower-than-two reaction stoichiometry is observed.Heterogeneous reactions occurring at the reactor wall seem to be essential in the reaction mechanism. The NO3 wall conversion to NO2 and the N2O5 wall scavenging in the presence of H2O are suggested to account for the observed stoichiometric factors. 相似文献
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Agusa T Kunito T Yasunaga G Iwata H Subramanian A Ismail A Tanabe S 《Marine pollution bulletin》2005,51(8-12):896-911
Concentrations of trace elements (V, Cr, Mn, Co, Cu, Zn, Ga, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) were determined in muscle and liver of 12 species of marine fish collected from coastal areas in Malaysia. Levels of V, Cr, Mn, Co, Cu, Zn, Ga, Sr, Mo, Ag, Cd, Sn, Ba and Pb in liver were higher than those in muscle, whereas Rb and Cs concentrations showed the opposite trend. Positive correlations between concentrations in liver and muscle were observed for all the trace elements except Cu and Sn. Copper, Zn, Se, Ag, Cd, Cs and Hg concentrations in bigeye scads from the east coast of the Peninsular Malaysia were higher than those from the west, whereas V showed the opposite trend. The high concentration of V in the west coast might indicate oil contamination in the Strait of Malacca. To evaluate the health risk to Malaysian population through consumption of fish, intake rates of trace elements were estimated on the basis of the concentrations of trace elements in muscle of fish and daily fish consumption. Some specimens of the marine fish had Hg levels higher than the guideline value by US Environmental Protection Agency (EPA), indicating that consumption of these fish at the present rate may be hazardous to Malaysian people. To our knowledge, this is the first study on multielemental accumulation in marine fish from the Malaysian coast. 相似文献