诱导期法对过饱和铝酸钠溶液初级成核过程的研究

建立一套用电导率法在线跟踪测定过饱和铝酸钠溶液初级成核诱导期的实验装置,将诱导期与经典的初级成核理论相结合,对涉及溶液初级成核过程的多种性质进行了定量研究,包括初级成核自由能,临界晶核粒度,临界成核分子数和固液界面张力等。实验结果表明,该套仪器具有很高的灵敏度,能方便准确地测定诱导期初级成核诱导期,T=323 K时,对于饱和度S=3.8~4.8的铝酸钠溶液,得到的结果:ΔGc=1.3×10-19J,rc=1.1~1.3 nm,γ=25.6 mJ/m2,Nc=3~8,与有关的文献报道相一致。     

超声波对蒸发结晶法制备仲钨酸铵过程的影响

研究了超声波对制备仲钨酸铵晶体的影响,探讨了超声波对仲钨酸铵的结晶时间、晶体粒度和晶型的影响。试验表明:超声波缩短了仲钨酸铵结晶的时间;超声波作用下制备的仲钨酸铵晶体粒度更小,分布更均匀;超声波并没有改变仲钨酸铵晶体的晶型,但所得到的晶体的d值与文献d值吻合更好,表明超声波有利于仲钨酸铵晶体的制备。     

氧化铝凝胶烧结过程中晶体生长及其抑制

运用XRD／SEM等手段，研究了拟薄水铝石凝胶烧结过程中α-Al2O3晶体的生长，溶胶-凝胶过程不改变拟薄水铝石的本质结构，只是使得其结构更加不完善。在凝胶烧结过程中，α-Al2O3晶体主要有3种形式的颗粒聚合体生长，由于固相传质，大小颗粒将发生融合，即聚合生长，结果是大颗粒变大，小颗粒消失，通过加入一定的晶体生长抑制剂，制备了微晶的氧化铝陶瓷。     

Real-solution stability diagrams for copper-ammonia-chloride-water system

A comprehensive thermodynamic model, which combined the Helgeson-Kirkham-Flowers (HKF) equation of state for standard-state thermodynamic properties of all species with realistic activity coefficient model developed by BROMLEY, was used to calculate the thermodynamic equilibrium, and a graphical method was developed to construct predominance existence diagrams (PED) for copper-ammonia-chloride in the presence of realistically modeled aqueous solutions. The existence of the different predominant chemical species for Cu(II) predicted by the diagrams was corroborated by spectrophotometrical studies and X-ray diffractometry. The simulated and experimental results indicate that the predominance of a given species in solution strongly depends on the pH value in this system. More quantitative information on real copper hydrometallurgy in the presence of ammonia and chloride can be obtained from these diagrams compared with the conventional predominance existence diagrams.     

Effects of combination modes of favorable growth unit of Al（OH）3 crystals precipitating on Van der Waals and chemical bond force

The dipole moment, total energy, atomic charge, orbital population and orbital energy of four representative combination models of the favorable growth unit Al6（OH）18 （H2O）6 of Al（OH）3 crystals precipitating are calculated by ab initio at RHF/STO-3G, RHF/3-21G, RHF/6-31G levels and DFT at RB3LYP/STO-3G, RB3LYP/ 3-21G, RB3LYP/6-31G levels with Dipole ＆ Sphere solvent model. The effect of various combination models on Van der Waals force is analyzed using dipole moment and molecular radius, and that on chemical bond force is analyzed using total energy, orbital population and orbital energy.     

Electrochemical performance of multiphase nickel hydroxide

The high density nano-crystalline multiphase nickel hydroxide containing at least three doping elements was synthesized and its electrochemical characteristics were studied. The electrochemical behavior of the high density spherical multiphases α-Ni（OH）2 were also investigated. The results show that the structure of the material is a mixed phase of α-Ni（OH）2 and β-Ni（OH）2, which has a the same stabilized structure as α-Ni（OH）2 during long-term charge/discharge process. High density spherical multiphases α-Ni（OH）2 have a much better redox reversibility, a much lower oxidation potential of Ni（ Ⅱ） than the corresponding oxidation state in the case of β-Ni（OH）2, and a much higher reduction potential. They exchange one electron during electrochemical reaction and have a higher proton diffusion coefficient. The mechanism of the electrode reaction is proton diffusion, and the proton diffusion coefficient is 5.67×10^-10 cm^2/s. Moreover, they reveal a higher discharge capacity than β-Ni（OH）2/β-NiOOH because they exchange one electron per nickel atom during charge/discharge process.     

Bond population analysis on combination of favorable growth unit of Al（OH）3 crystals

1 Introduction It is well known that there are many technical puzzles on how to enhance the strength of alumina in the domestic production of alumina. From the actual research it has been indicated that the strength of alumina is mainly related to the str…     

O2/Ar气氛中仲钨酸铵热分解制备的WO3光催化分解水析氧活性

在不同组成O2/Ar混合气体条件下,于700℃将仲钨酸铵加热分解制备WO3催化剂。采用XRD、XPS、DRS等技术对催化剂进行表征,考察催化剂在电子接受体Fe3 溶液体系下的光催化分解水析氧活性。结果表明:Ar含量增大,WO3催化剂表面氧空位增加,光催化析氧活性增大,纯Ar条件下所得的WO3催化剂光催化析氧活性最高。研究了Fe2 对光催化分解水析氧活性的影响,在Fe3 离子作为电子接受体的光催化分解水析氧反应中,一定浓度的Fe2 离子能明显抑制WO3的析氧活性,当Fe2 离子和Fe3 离子的浓度相当时,WO3催化剂完全失去光催化析氧活性。     

微晶氧化铝磨料的特性及制造

主要论述了微晶氧化铝磨料的概念、特性、在磨料行业的特殊地位，微晶氧化铝磨料的生产工艺，并简要介绍了世界上微晶氧化铝磨料的状况，以及微晶氧化铝磨料在中国的现状。     

Structure and bonding orientation of favorable growth unit Al6（OH）18（H2O）6 of gibbsite

1INTRODUCTION Thecrystalgrowthcharacteristicsofgibbsite insupersaturatedsodiumaluminatesolutionwere extensivelyinvestigated[15],butthestructureand formofthegrowthunitwerenotrelated.Firstly,Vanstratenetal[6]indicatedthatthegrowthunit transitionstateofaluminateacidradicalexistedin thecrystallizationofgibbsitefromalkalinesodiumaluminatesolution.Parkinsonetal[7]figuredout thatAl(OH)-4,Al(OH)2-5andAl(OH)3-6would belikelytobecomegrowthunitsofgibbsitefromtheviewpointofcrystalsurfacebindingene…