梅山高炉瓦斯泥综合利用的研究

分析研究国内外高炉粉尘使用情况，结合梅山高炉瓦斯泥的性质、特征和现状，提出用弱磁-强磁选的选矿方法，从梅山高炉瓦斯泥中回收铁精矿的设想。通过试验室试验，取得了较好的技术经济指标，达到了预期效果，并可降低锌含量。     

低品位氧化锌粉矿制粒及碱性浸出

小于2 mm的氧化锌矿(含锌5.17%)与5%的水泥混合,制粒并固化,所得颗粒直径5~8 mm。固化3天、10天、45天的颗粒用碱性溶液浸出,最大浸出率分别为92.2%、87.3%、72.9%。减少固化时间能够缩短反应时间、增加颗粒中锌的溶解以及减少浸出剂中初始锌浓度的影响。实验表明颗粒最少需固化3天。动力学研究表明浸出过程受浸出剂通过脉石层的扩散控制,表观速率常数分别为3.51×10-2d-1、8.09×10-3d-1和4.74×10-3d-1。     

Effect of Ga doping on micro/structural, electrical and optical properties of pulsed laser deposited ZnO thin films

Undoped and Ga doped ZnO thin films (1% GZO, 3% GZO and 5% GZO) were grown on c-Al₂O₃ substrates using the 1, 3 and 5 at. wt.% Ga doped ZnO targets by pulsed laser deposition. X-ray diffraction studies revealed that highly c-axis oriented, single phase, undoped and Ga doped ZnO thin films with wurtzite structure were deposited. Micro-Raman scattering analysis showed that Ga doping introduces defects in the host lattice. The E₂^High mode of ZnO in Ga doped ZnO thin film was observed to shift to higher wavenumber indicating the presence of residual compressive stress. Appearance of the normally Raman inactive B₁ modes (B₁^Low, 2B₁^Low and B₁^High) due to breaking of local translational symmetry, also indicated that defects were introduced into the host lattice due to Ga incorporation. Band gap of the Ga doped ZnO thin films was observed to shift to higher energy with the increase in doping concentration and is explicated by the Burstein-Moss effect. Electrical resistivity measurements of the undoped and GZO thin films in the temperature range 50 to 300 K revealed the metal to semiconductor transition for 3 and 5% GZO thin films.     

MIG Brazing of Galvanized Thin Sheet Joints for Automotive Industry

MIG welding of zinc-coated thin plates in the automotive industry leads to major issues, mainly zinc evaporation followed by a decrease of corrosion resistance, as well as residual strains and stresses difficult to minimize. The use of a lower heat input technique for joining galvanized steels would bring significant benefit, if the final overall mechanical properties of the joints are adequate for the application. The use of MIG brazing (MIGB) with the recently commercialized alloyed copper-based filler metal is an alternative worth considering. The present paper addresses the MIGB processes, describing the influence of the different shielding gases and the process parameters on the mechanical, corrosion, and metallurgical properties of the joint, when lower heat input procedures are targeted. The paper describes the influence of the gases on the mechanical properties of the brazed joint, both in normal conditions after joining and after corrosion in a salt water environment. Microstructural features of the different zones are discussed. Results of corrosion and tensile tests are presented and interpreted.     

Atomic layer deposition of thin films of ZnSe—structural and optical characterization

Thin films of sphalerite-type ZnSe were grown by atomic layer deposition (ALD) from elemental Zn and Se precursors. These films, grown on various substrates, show bright blue ‘edge’ emission accompanied by donor-acceptor pair emissions in the blue, green and red spectral regions. Red, green and blue emissions mixed together give a white color, with a color temperature between 2400 and 4500 K depending on a layer thickness and temperature. ZnSe grown by ALD is in consequence a promising material for the fabrication of semiconductor-based white light emitting thin film electroluminescence displays.     

Kinetic investigation of zinc electrodeposition from sulfate electrolytes in the presence of impurities and ionic liquid additive [BMIM]HSO4

The effects of some common impurities such as copper, iron, nickel, cobalt, lead and their interaction with an ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO₄ on zinc electrodeposition from acidic sulfate electrolyte were characterized in terms of the polarization behavior and the kinetics of zinc deposition using cyclic voltammetry and potentiodynamic polarization measurements. The results showed that these metallic impurities studied exerted some different changes in cyclic and cathodic polarization voltammograms. The addition of [BMIM]HSO₄ was observed to counteract the detrimental effects of these impurities and induced a blocking effect on the zinc electrodeposition process through its cathodic adsorption on the electrode surface. The adsorption of this additive shifted the electroreduction potential of zinc ions towards more negative values, restricted impurities ions from being electroreduced, and inhibited hydrogen evolution. Moreover, the kinetics analysis of cathodic polarization suggested that the presence of these impurities alone and in combination with [BMIM]HSO₄ had no effect on the Tafel slope and transfer coefficient but affected the exchange current density for the zinc deposition.     

Simulation of methylene blue adsorption by salts-treated beech sawdust in batch and fixed-bed systems

Batch and column kinetics of methylene blue adsorption on calcium chloride, zinc chloride, magnesium chloride and sodium chloride treated beech sawdust were simulated, using untreated beech sawdust as control, in order to explore its potential use as a low-cost adsorbent for wastewater dye removal. The adsorption capacity, estimated according to Freundlich's model, the Langmuir constant K(L) and the adsorption capacity coefficient values, determined using the Bohart and Adams' bed depth service model indicate that salts treatment enhanced the adsorption properties of the original material. Since sawdust is an industrial waste/byproduct and the salts used can be recovered as spent liquids from various chemical operations, this process of adsorbent upgrading/modification might be considered to take place within an 'Industrial Ecology' framework.     

ZnCl2-assisted Synthesis of ZnSe Polycrystal

A chemical-assisted element direct-reaction method is developed to synthesize ZnSe compound semiconductor material at a relatively low temperature (～1000 C). ZnSe polycrystal was obtained in the closed-tube systems with Zn-Se, Zn-Se-Zn(NH3)2Cl2, Zn-Se-NH4Cl and Zn-Se-ZnCl2. The as-synthesized samples were tested by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and analyzed by thermodynamic numerical method. The results demonstrate that the synthesis efficiency is higher than 99.96% for Zn-Se-ZnCl2 system at around 1000 C for 3 weeks. It also exhibits that not only temperature, but also low apparent ratio of volume and surface area of the source materials and higher ZnCl2 content are required to achieve high synthesis efficiency. A SeCl transporting reaction synthesis process is proposed based on the thermodynamic analysis.     

Transparent and conductive ZnO:Al thin films grown by pulsed magnetron sputtering in current or voltage regulation modes

Aluminium-doped zinc oxide (AZO) thin films have been prepared by pulsed magnetron sputtering from a ceramic oxide target in pure argon atmosphere. Sputtering processes were performed in current or voltage regulation modes at different pulsing frequencies up to 200 kHz. Several growth parameters (discharge power, substrate temperature and growth rate) as well as AZO film properties (crystalline structure, optical transmittance and electrical characteristics) have been measured and analysed as a function of the current or voltage applied, the pulsing frequency and the operation time. By adjusting these deposition parameters, AZO layers with resistivity as low as 1.0×10⁻³ Ωcm and average visible transmittance above 85% have been obtained at growth rate in the range 70-80 nm/min, at substrate temperatures below 150 °C.     

ZIF-8衍生La掺杂ZnO纳米颗粒的制备及其气敏性能

以ZIF-8及La掺杂ZIF-8为前驱体,经高温煅烧制备ZnO及La掺杂ZnO纳米颗粒.研究了La掺杂对ZnO纳米颗粒的形貌、晶体结构及气敏性能的影响.利用X射线衍射仪、扫描电子显微镜对材料的微结构进行表征,结果表明:La掺杂有利于获得更小粒径的类球形纳米结构,但La掺杂未改变ZIF-8及衍生ZnO纳米结构的晶体结构....