Luminescence of Oxygen-Deficient Centers in Quartz Glasses

Glass Physics and Chemistry - This paper presents the results of studying the absorption, luminescence, and excitation spectra of oxygen-deficient centers (ODCs) in glasses obtained from quartz raw...     

由石棉尾矿生产沉淀二氧化硅

探讨了以石棉尾矿为原料，采用湿法生产沉淀二氧化硅和轻质氧化镁，副产硫酸钠，氧化铁红等化工原料的最佳工艺采参数，充分利用了陕西省的矿产资源，解决了石棉尾矿的环境污染问题。     

用油页岩渣制备白炭黑的工艺

以油页岩渣为原料,经950℃煅烧4 h, 加入3.30 mol/L NaOH溶液于100℃处理4 h,用HCl酸化至pH 8~9时,SiO2的浸出率为75.8%. 经X射线荧光分析,白炭黑产品中的SiO2纯度为91.8%;经FT-IR检测白炭黑的化学结构为水合二氧化硅;经XRD分析,白碳黑为无定型结构;TEM图像显示白炭黑的形貌近似为球状粒子,平均粒径在50 nm以下. 白炭黑的比表面积(BET)为114 m2/g, pH值为5.5~6.0,加热减量为5.82%, 1000℃灼烧减量为6.16%,产品符合中国行业标准HG/T 3061-1999的要求.     

铁尾矿制备白炭黑的实验研究

以铁尾矿和NaOH为原料,利用化学沉淀法成功制备了无定型白炭黑,并研究了制备的工艺条件.用X射线衍射仪、红外光谱仪、扫描电镜、透射电镜和X射线荧光光谱仪对所制白炭黑的物相结构、粒度、形貌和成分进行分析.结果表明,白炭黑中的SiO2纯度为92.3%,化学结构为无定型的水合二氧化硅,形貌近似球状粒子,粒径在150nm以下.白炭黑的比表面积(BET)为108 m2/g,10%悬浮液中pH值为5.5～6.0,加热减量为5.42%,1000℃灼烧减量为6.16%.产品符合中国行业标准HG/T 3061-1999的要求.     

Electrical Properties of Precipitated Lignins from Different Black Liquors

Abstract

Some corelations over the structure and dielectric properties of precipitated lignins from different waste black liquors of various modified soda and kraft pulping of bagasse have been discussed. The dielectric and the electrical properties at the same temperatures and frequencies ranges for the tested samples showed some differences which seems to be attributed to the difference in the structure and intermolecular interaction between lignin molecules. These differences are discussed on the basis of the molecular structure obtained from the infrared spectra. The conduction mechanism in the case of kraft and kraft sulfite lignins is due to electron transfer from the valence band to the conduction band by thermal activation.     

利用硅灰石生产白炭黑的实用技术研究

研究了沉淀法生产白炭黑的工艺技术 ,制定了硅灰石生产白炭黑的实用工艺流程 ,经检验白炭黑产品达一级品水平     

High-Temperature Oxidation Behavior of Solution Precursor Plasma Sprayed Nanoceria Coating on Martensitic Steels

Solution precursor plasma spray (SPPS) is used to deposit nanoceria coating on a 410 martensitic stainless steel. The process of pyrolysis in converting the cerium nitrate solution to cerium oxide, the microstructure and the surface chemistry is confirmed by thermodynamic calculations, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. Subsequent exposure of the coated steel in atmospheric air to cyclic oxidation at 1000°C revealed excellent corrosion resistance of the steel in presence of the SPPS-processed nanoceria coating. The formation of the nanostructured (10–100 nm) ceria coating is studied using transmission electron microscopy. Relative Ce⁴⁺ and Ce³⁺ concentration in the coating was determined from XPS high-resolution spectrum. Cross-section scanning electron microscopy showed the presence of an impervious nature of the protective layer with reduced scale thickness in the coated-oxidized sample. After a pre-oxidation treatment at 1273 K of the coated specimen, the oxidation kinetics showed a significant decrease as compared with the uncoated martensitic steel.     

Phase Equilibria and Physical Properties of Oxygen-Deficient Zirconia and Thoria

The compositions of anion-deficient zirconia and thoria in equilibrium with O₂ were measured from 1 to 10⁻⁶ atm and 1400° to 1900°C; for ZrO_{2- x} (po₂ in atm, and T in °K), log x∼−0.890-[(0.400×10⁴)/ T ]-[(log p )/6]; for ThO_{2- x} , log x∼−1.870-[(0.340×10⁴)/ T ]-[(log p )/6]. The ZrO_{2- x} -Zr boundary was located at x=0.014 at 1800°C; thoria was single-phase over the entire range. Consistent results were obtained when O₂/inert gas mixtures were used, but use of H₂/H₂O and CO/CO₂ at 1000° to 1200°C gave abnormal and, in the latter case, erratic data; side reactions in these atmospheres are inferred. The monoclinic-tetragonal phase change of ZrO₂ and the lattice thermal expansion, room-temperature Young's modulus, and strength properties of ZrO₂ and ThO₂ bodies were not appreciably altered by oxygen deficiency. The lattice dimensions decreased slightly with departure from stoichiometry.     

Modeling Anomalous High-Temperature Adsorption from Binary Mixtures

The working dynamic activity of an adsorbent rises with increasing temperature owing to the equilibrium shifting toward the desorption of initial components and vacant positions being occupied by the adsorbable impurity.     

纯橄岩酸碱离解法制备白炭黑的工艺比较

分别采用了酸碱离解2种方法从纯橄岩制备白炭黑,其中碱离解的实验条件为4 mol/LNaOH,100℃下,离解4 h,SiO2的浸出率36.55%;酸离解法的实验条件为4 mol/L H2SO4,90℃下,离解2 h,SiO2的浸出率为86.25%。酸离解法制备的白炭黑经测定纯度为96.28%;经FT-IR检测白炭黑的化学结构为水合二氧化硅;TEM图像显示白炭黑的形貌近似球状粒子,平均粒径50 nm以下。白炭黑pH值6.0-7.0,加热减量5.92%,1000℃灼烧减量为6.12%,产品符合中国行业标准HG/T3061-1999的要求。     

超细种分氢氧化铝微粉的表面改性

结合工厂铝酸钠溶液种分制备超细氢氧化铝粉工艺,研究了表面改性温度、改性方式、表面改性剂的复配等对表面改性产品活化指数、吸油值、电导率的影响规律。结果表明,在小于130℃内提高表面改性温度、强化表面改性搅拌强度和采用表面改性剂的复配,均有利于提高氢氧化铝微粉表面改性效果;而太高温度(130℃)会降低表面改性效果。表面改性效果主要取决于表面改性剂官能团性质。与硬脂酸复配还能降低产品的电导率,减少硅烷偶联剂用量。改性氢氧化铝的吸油值和活化指数变化规律不完全一致。     

Phase Characterization of Precipitated Zirconia

The phase compositions of undoped and europium-doped zirconia samples, obtained by precipitation and thermal treatment from 350° to 1000°C, have been investigated by powder X-ray diffractometry, infrared spectroscopy, and cathodoluminescence spectroscopy. The low-temperature stabilization of tetragonal zirconia is mainly controlled by the presence of anion additives, such as ammonium chloride. The influence of the crystallite size is less important. Cathodoluminescence spectra show a structural similarity between tetragonal and amorphous zirconia.     

Investigation of In-Flight Glass Melting by Controlling the High-Temperature Region of Multiphase AC Arc Plasma

A large volume discharge produced by a stable 12-phase alternating current (AC) arc plasma is preferable to melt the granulated glass materials for time and energy saving. The discharge behavior and the high-temperature region of the plasma system can be controlled by the electrode configurations. In this study, the spatial characteristics of the arc discharge were examined by image analysis with a high-speed camera. The melting characteristics of alkali-free glass particles were investigated by microscope and X-ray diffractometry. This is the first time to investigate the relationship between spatial characteristics of plasma and glass particle property. Results show the arc existence area is strongly related to the electrode configuration. Distributions of in-flight powders and the spatial characteristics of arc are important factors when using multiphase AC arc for in-flight melting. This study provides information of efficient particle treatment according to the electrode configuration.     

沉淀二氧化硅的应用与发展

本文简述了沉淀二氧化硅的制备方法、性质 ,着重介绍了它在硅橡胶、涂料及牙膏中的应用 ,并对沉淀二氧化硅的发展方向进行了概括性分析     

铝盐在沉淀法白炭黑中的应用

简述了铝盐在沉淀法白炭黑中的应用现状，添加铝盐对白炭黑物理化学性能的影响和含铝沉淀法白炭黑的用途进行了阐述。