CO hydrogenation over potassium-promoted Fe/carbon catalysts

The effects of potassium on the catalytic behavior in CO hydrogenation over K-promoted Fe/carbon catalysts having low K/Fe ratios were investigated. Even though the doses of potassium were low the promotional effects were pronounced, especially on the olefin-to-paraffin ratio, and theC ₃ toC ₄ olefin selectivities of the K-promoted catalysts were as high as 51 to 66 mol%. Over the catalysts having no or low potassium content the olefin-to-paraffin ratio and the ratio of the CO₂ formation rate to the rate of CO conversion to hydrocarbons remained roughly the same regardless of temperature, while over the K-promoted catalysts having higher potassium content they increased with temperature. Formation of significant amounts of filamentous carbon was observed in the K-promoted catalysts; however, the carbon deposition did not appear to affect the inherent activity and selectivity of the K-promoted catalysts.     

贵州省磷化工现状及发展前景

阐述贵州磷资源、煤炭、电力基本情况及在全国的地位和我省发展磷化工的重要意义。介绍我省磷化工生产现状、生产能力、实际产量、产品出口等情况。对世界磷化工产品市场需求，我国和我省的磷化工到2000年的发展情况，达到的目标进行初步援测和构想，并对我省磷化工发展对策进行探讨，提出几点建设性意见。     

A porous mixed-valent iron MOF exhibiting the acs net: Synthesis, characterization and sorption behavior of Fe3O(F4BDC)3(H2O)3·(DMF)3.5

A new mixed-valent iron MOF, formulated as Fe₃O(F₄BDC)₃(H₂O)₃·(DMF)_3.5 (1), has been synthesized by using a perfluorinated linear dicarboxylate to link trigonal prismatic Fe₃(μ³-O)(O₂C–)₆ clusters. The structure refinement based on single crystal X-ray diffraction data collected from 1 reveals the material exhibits the acs topology with large channels along the crystallographic c-axis. Due to the presence of fluorine atoms the organic link, 2,3,5,6-tetrafluorobenzene-1,4-dicarboxylate (F₄BDC), has a 63° torsion angle between the carboxylate and aromatic planes, resulting in larger channels compared to those in the isoreticular material MOF-235. While few iron-based MOFs have demonstrated porosity, nitrogen and hydrogen sorption experiments carried out at 77 K proved the porosity of outgassed 1, which has a Langmuir surface are of 635 m²/g and a gravimetric capacity of 0.9 wt% of hydrogen at 1 bar.     

Exploration of mesoporous structure of tunisian raw and acid-leached phosphate ore particles

Rock phosphate fractions were examined for their porous structure by nitrogen adsorption. The pore size distribution and the shape of pores does not seem to depend on the particle size. The specific surface area values present two regions, one above and one below that of the particles with 125 μrn diameter. Particles of a given size were leached with dilute phosphoric acid (1.5 mass% P₂O₅) at 25°C. It was observed that there is a widening of the initial pores during leaching. The particles collected at the initial period of the reaction are pitted and those collected at the final period are disintegrated.     

Chemical Reaction Engineering and Research and development of gas solid systems

A general procedure is proposed for innovative research and development of gas-solid reactor systems, with a brief explanation of the significance of each step in the procedureBased upon the contacting mode between gas and solid phases, as well as the ways of supplying thermal energy to the reacting regions, various types of gas-solid reactor systems are classified by using tables of so called “matrix” form, for thermal cracking and gasification of heavy oils, gasification of coal, gasification of solid waste, calcination of limestone, clinkering of cement and reduction of iron ore.The importance of fundamental concepts is emphasized for successful research and development by presenting several examples; namely, calcination of limestone, thermal cracking of heavy oils and gasification of solid waste materials.In connection with the direction in which fundamental research should be oriented, four primary ways of thinking are proposed, which can be applied to obtain innovative ideas for further research and development in this field.One example of the author's practical experience was selected to show the role of the fundamental research in the course of large scale development. Finally the author outlines the role of chemical reaction engineering to innovate the novel gas-solid reactor systems which may be inevitable for simultaneous solution of the three big E's; namely, Energy, Environment and Economy.     

自含砷合碳难处理金矿中提取金的研究─Ⅰ.氨水脱砷-石灰加压氧化-氰化

针对甘肃省坪定金矿含金、砷高、金部分地赋存于脉石、脉石为碱性、属于难选难冶矿的特点，提出了氨水脱砷－石灰加压氧化－氰化新工艺．当原矿含金8．7g／t及13．0％砷时，砷可脱除95％，金可浸出85％．技术及经济指标预计均较满意．     

硫酸脲分解磷矿反应机理探讨

以硫酸脲分解磷矿是一种新的N、P复肥生产方法,硫酸脲分解磷矿有其特殊的反应机理。利用在线显微摄像与物化分析相结合,可以很好地表征硫酸脲分解磷矿的反应机理。实验表明:硫酸脲与磷矿在液固接触的界面微区进行反应,反应微区内有离解、反应、结晶、复合等过程,并伴随有晶型转变。反应生成的硫酸钙晶体复盖反应粒子表面,形成包裹层增大传质阻力。反应物质通过CaSO40.5H2O晶膜的传递阻力是影响整个反应过程的重要因素。     

Electrocatalyst materials for fuel cells based on the polyoxometalates—K7 or H7[(P2W17O61)Fe(H2O)] and Na12 or H12[(P2W15O56)2Fe4(H2O)2]

Free acids of the iron substituted heteropoly acids (HPA), H₇[(P₂W₁₇O₆₁)Fe^III(H₂O)] (HFe1) and H₁₈[(P₂W₁₅O₅₆)₂Fe^III₂(H₂O)₂] (HFe2) were prepared from the salts K₇[(P₂W₁₇O₆₁)Fe^III(H₂O)] (KFe1) and Na₁₂[(P₂W₁₅O₅₆)₂Fe^III₄(H₂O)₂] (NaFe4), respectively. The iron-substituted HPA were adsorbed on to XC-72 carbon based GDLs to form HPA doped GDEs after water washing with HPA loadings of ca. 1 μmol. The HPA was detected throughout the GDL by EDX. Solution electrochemistry of the free acids are reported for the first time in sulfate buffer, pH 1-3. The hydrogen oxidation reaction was catalyzed by KFe1 at 0.33 V, with an exchange current density of 38 mA/cm². Moderate activity for the oxygen reduction reaction was observed for the iron substituted HPA, which was dramatically improved by selectively removing oxygen atoms from the HPA by cycling the fuel cell cathode under N₂ followed by reoxidation to give a restructured oxide catalyst. The nanostructured oxide achieved an OCV of 0.7 V with a Tafel slope of 115 mV/decade. Cycling the same catalysts in oxygen resulted in an improved catalyst/ionomer/carbon configuration with a slightly higher Tafel slope, 128 mV/decade but a respectable current density of 100 mA/cm² at 0.2 V.     

科技创新与钢铁科技进步

建设创新型国家是我们中华民族的历史责任。“自主创新、重点突破、支撑发展、引领未来”的16字方针应当成为我们未来创新活动的指南。建设创新型国家把自主创新放在首位,并提出了引领未来的高标准要求。钢铁科技创新必须突出重点,抓住创新成果产业化这个关键,支撑起行业和国民经济的发展。     

Mechanistic peculiarities of the N2O reduction by CH4 over Fe-silicalite

Transient isotopic studies in the temporal analysis of products (TAP) reactor evidenced the importance of the lifetime of oxygen species generated upon N₂O decomposition on extraframework iron sites of Fe-silicalite for methane oxidation at 723 K. Fe-silicalite effectively activates CH₄ when N₂O and CH₄ are pulsed together in the reactor. However, these oxygen species gradually become inactive for methane oxidation as the time delay between the N₂O and CH₄ pulses is increased from 0 to 2 s.