The Effect of Copper Bearing Particles Liberation on Copper Recovery from Smelter Slag by Flotation

The impact of the liberation of copper bearing particles on copper recovery in the flotation has been the subject of research in this paper. Tests have shown that grinding of material highly impacts the recovery rate in the flotation process. Results of flotation of smelter slag samples with different contents of grain size fraction ?74 µm: 50%, 60%, 70%, 80%, and 90%, have shown that by an increasing the content of the ?74 µm fraction in the feed, the recovery of copper was increasing as well. The highest recovery rate of copper was obtained with 90% of grain size fraction ?74 µm in the feed. The microscopic analysis of concentrates have shown that increased content of grain size fraction ?74 µm, was followed by increased contribution of liberated particles in the 0 to 70 µm fraction, while the contribution of middlings had been decreasing.     

Effect of Atmosphere on the Electrical Conductivity of Sodium Tungstophosphate Glasses

The dc electrical conductivity of sodium tungstophosphate glasses was measured as a function of glass composition, melting history, and ambient atmosphere. The color of the glasses was a strong function of both glass composition and melting history. The electrical conductivity was found to be strongly dependent upon the concentration of protons in the surrounding atmosphere. The colorless glasses were found to be electrochromic only so long as protons were present in the atmosphere. A model is suggested to explain these results.     

The Influence of Potassium Bromide on the Properties of Nanocrystalline Copper Halide Particles in Sodium Aluminoborosilicate Glasses

The influence of potassium bromide on the properties of the copper halide phase in sodium aluminoborosilicate photochromic glasses is investigated by optical and exciton spectroscopy and the small-angle X-ray scattering (SAXS) technique. It is found that potassium bromide introduced in the course of synthesis affects the properties of the nanocrystalline copper halide phase.     

Toughening of Glasses by Metallic Particles

The role of elastic, thermoelastic, and interfacial properties in the toughening of a brittle matrix by metallic second-phase particles was studied. Two composites were studied: glass+partly oxidized Ni particles (thermal expansion coefficient of the glasses lower than, equal to, and higher than that of Ni) and glass+partly oxidized Al particles (thermal expansion and elastic moduli equal). Weak interfacial bonding between the nickel and its oxide and developed stress concentrations are the major toughness limitations found in the glass/Ni composites. When the thermal expansion coefficient and elastic modulus of the second phase are sufficiently greater than that of the glass matrix, a propagating crack will bypass the particles. When the thermal and elastic stresses are minimized and satisfactory bonding is achieved (glass/Al composites), a 60x toughness increase was realized.     

Analysis of Interaction between RuO2 and Glass by Growth of RuO2 Particles in Glasses

The RuO₂-glass interaction has been studied by analyzing the growth of RuO₂ particles in glasses. The size of RuO₂ particles was determined by TEM and X-ray line broadening. The RuO₂/glass interfacial energy was evaluated by spreading and penetration experiments.

Changes in size and shape of RuO₂ particles indicated that coarsening proceeded by the diffusion-controlled dissolution-precipitation process. The growth rate of RuO₂ particles at temperatures giving the same viscosity was dependent on the glass composition. Kinetics of the Ostwald ripening and values of glass surface energy implied that the solubility of RuO₂ in glass is a critical factor. Results indicated that the solubility of RuO₂ in glass decreases with increasing PbO content and with increasing SiO₂ substitution for B₂O₃. Dissolution of Al₂O₃ from substrate retarded the Ostwald ripening.     

以PEG600为模板液相还原法制备片状铜粉

采用液相化学还原法,在模板剂PEG600存在的情况下,以NaH2PO2为还原剂,制备了粒径10~40 mm、厚1.5~2.5 mm、表面光滑的片状超细铜粉. 考察了还原溶液pH值、反应温度、CuSO4浓度、PEG600加入量对片状铜粉的影响. 实验得出优化工艺条件为：CuSO4浓度0.2 mol/L, NaH2PO2浓度0.14 mol/L,模板剂PEG600加入量8 mL,温度80℃, pH 0.5. 粉末XRD谱图和SEM分析显示,产品为较为规则的片状铜粉.     

铜酞菁同质多晶现象的研究及其超细粒子的制备

采用路易斯酸配位法溶解了铜酞菁，并对路易斯酸溶解铜酞菁的机理进行了简单讨论，同时研究了溶解过程中不同溶剂对铜酞菁晶型的影响．最后，用路易斯酸溶解配位法和微射流纳米分散技术相结合的方法成功制备了铜酞菁超细粒子，并用激光粒度仪、原子力显微镜、紫外可见分光光度计对超细粒子的粒径和吸收光谱进行了表征．     

聚苯胺/纳米CuO复合颗粒的制备及其性能

采用原位掺杂聚合法制备聚苯胺/CuO纳米复合粒子,对其进行了表征,考察了其催化性能和抗菌性能.结果表明,聚苯胺在CuO表面包覆,得到棒状核-壳结构的聚苯胺/纳米CuO复合粒子,其具有良好的催化性能,能加速H2O2分解,累积产气1500 m L;随CuO含量增加,复合粒子电导率明显下降,导电性能逐渐减弱,纳米CuO含量为0.6g时,导电能力很弱,电导率为0.02S/cm.随CuO含量增加,复合粒子抗菌性能逐渐增强,金黄色葡萄球菌和大肠杆菌的抑菌圈直径分别达35.8和19.6mm.     

Effect of Mixing on the Nucleation and Growth of Titania Particles

Aerosol processes that produce titania particles by reacting gaseous precursors (such as titanium tetrachloride) initially must mix the precursor into the oxidizer at elevated temperatures to initiate the formation of product. Oftentimes the rate of reaction is sufficiently large as to be mixing limited. Thus the rate of mixing of the reacting species will control the chemistry and morphological properties of the particles that are produced. The interplay between mixing, nucleation, and growth in these systems is difficult to observe experimentally due to the small time scales that are involved and the spatial limitations of most diagnostics. An alternative approach is direct numerical simulation (DNS). DNS refers to a class of numerical solutions of the three-dimensional time-dependent governing equations for a particular system in which no turbulence modeling assumptions are made. To within the precision of the numerical algorithm, DNS can be thought of as a numerical experiment. Here we apply DNS to the mixing, reaction, nucleation, and growth of titania particles formed from the reaction of titanium tetrachloride with oxygen. The simulation solves for the velocity, species concentration, and eight moments of the particle size distribution using a combination of a pseudospectral method (for the velocity) and a compact finite difference scheme (for all of the scalars). The results show that increasing the rate of mixing increases the rate of particle formation while decreasing the variance in the particle size distribution. However, for a given extent of reaction, poorer mixing leads to larger mean particle sizes and larger standard deviations. The results are most easily interpreted in terms of the reaction volume between the unmixed reactants, where most of the reaction occurs. Based on this analysis, we present rules of thumb for controlling the particle size distribution in aerosol reactors.     

Effect of Second-Phase Particles on Grain Growth in Calcite

Grain growth in polycrystalline caicite (CaCO₃) at 800°C and 300-MPa confining pressure is inhibited by the addition of Al₂O₃ particles; volume fractions of second phase (f) ranged from 0.02 to 10.0 vol%, and several powders with different average particle size were used. The stable grain size reached during heat treatment was inversely proportional to l/f^m where m varied from 0.3 to 0.55 — agreeing with results from other grain growth experiments in ceramics and metals, and with models developed for particles located at grain boundaries and grain corners, but not agreeing with models developed for random dispersions. The dependence of the stable grain size on second-phase particle size in these experiments was less systematic, possibly because of variations in the particle size distributions used, or because of particle agglomeration effects. In the single-phase aggregates, the growth kinetics were consistent with a normal grain growth equation with n=3, although uncertainties were large.     

废弃玻璃水热热压-煅烧法制备泡沫玻璃

泡沫玻璃是一种性能优越的新型环保建筑材料.本文以废弃玻璃和水为原料,利用水热热压-煅烧法制备泡沫玻璃,考查了水热压力、煅烧时间、煅烧温度和升温速率对样品形貌、体积密度及抗压强度等性能的影响,并通过TG-DTG、XRD、SEM等对过程原理进行了分析.结果表明煅烧温度是影响产品质量的主要因素,水热压力、煅烧时间、升温速率对其影响不大.得到的最优条件为:水热压力8.5 MPa、水热温度200℃下反应45 min,以5℃/min的速率加热至800℃煅烧1h,在此条件下制得的泡沫玻璃发泡均匀,密度为0.24 g/cm3左右,抗压强度可达1.6MPa.     

Effect of Sintering Atmosphere on the Densification and Abnormal Grain Growth of ZnO

When a ZnO powder compact is sintered at 1450°C in air, the grains at the surface region of the specimen are observed to grow abnormally. Such abnormal grain growth does not occur when the specimen is sealed in a small cylindrical quartz tube and sintered at the same temperature. The higher rate of densification at the near-surface region than in the interior is suggested to trigger the abnormal grain growth observed.     

Preparation of Oxide Glass Films by Reactive Sputtering

A method of depositing oxide glass films on a substrate is presented. The method involves the sputtering of a metal or semiconductor electrode in an oxidizing atmosphere (so-called reactive sputtering). The films obtained are of good quality, unstrained, and adhere well to the substrate. Films of considerable thickness can be deposited and the substrate need not be heated during the process. The preparation of lead tellurite glass films, silica and germania glass films, silicate glass films, and stannate glass films is described. Some data on the kinetics of film growth and on the physical properties of these materials are presented.     

The Effect of Large Particles on Microfiltration of Small Particles

The effects of the presence of large latex (1 m) particles on the microfiltration of small gold (50 nm) colloidal suspensions have been investigated using hydrophobic 0.22 m polyvinylidene fluoride (GVHP) micro-filtration (MF) membranes. Gold sol was filtered through the membrane with or without prefiltration of latex suspension. The characteristics of the cake formed on the membrane surface depends not only on the intrinsic properties of the particles in the feed but also depends on the nature of the mixture. The type of cake formation (e.g. a cake of small particles on the top of large particles or a cake of mixed particles) affects the cake properties due to the combination effect. This can be explained by the type of filling of the voidage between large particles with small particles. Various combinations of these particles result in cakes with different resistances. The understanding of the combination effect and the type of cake formation has a potential application for fouling minimization.Fouling is surprisingly serious in microfiltration of the feeds containing mixed particles. Separation of large particles prior to the microfiltration of suspension of small particles can reduce cake resistance and minimize fouling.     

微颗粒表面磁控溅射镀金属膜

采用磁控溅射方法,开展了在微颗粒表面镀金属膜的实验研究.研究开发了一种在微颗粒表面真空镀金属膜的方法及设备,微颗粒包括空心微珠、不同粒度的碳化硅微粉等,所镀的金属包括铝、银、铜、钴、镍等.实验与分析结果表明,通过控制微颗粒的运动方式,采用磁控溅射镀金属膜,可以在微颗粒表面镀上均匀性好、附着力强和致密性好的金属膜.     

Preparation of High-Silica Glasses from Colloidal Gels: I, Preparation for Sintering and Properties of Sintered Glasses

A new method for preparing fused silica and high-silica glasses through the sougel process is described. Ordinarily, fused silica is formed by fusion of silica at 1900° to 2000°C. The method described consists of preparation of a porous body by mixing colloidal silica with water, drying, redispersion, molding by casting, followed by gelation, drying, and sintering at 1450° to 1500°C. The sintering is facilitated by addition of 3 to 5 wt% B₂O₃. The process of dispersion-drying-redispersion (so-called "double process") results in formation of a two-mode pore structure which permits drying of cast tubes and rods without breakage. The preparation of the porous bodies, study of pore structure, and properties of resulting glasses are described in Part I, the sintering is considered in Part II, and the mechanism of gel formation is interpreted from infrared spectroscopy studies in Part III.     

Effect of Sonication in the Preparation of Activated Carbon Particles on Adsorption Performance

The impact of acid and base adsorption capacities of activated carbon (AC) particles with activation condition, contact time, specific surface area (SSA), particle size, concentration, and temperature was studied. AC was pre-treated by sonication to improve the surface characteristics and enhance its adsorption capacity. Sonication increased the SSA of AC. SEM imaging showed good dispersion and uniform AC particles with an average diameter of about 0.6 μm. The adsorption results demonstrated that AC surfaces possessed effective interactions with acids and bases, and the greatest adsorption capacity was achieved with CH₃COOH, where data were analyzed by Freundlich and Langmuir isotherms. It was found that the isotherm data correlated well with the Freundlich isotherm. Adsorption of raw AC particles increased under sonication conditions. The adsorption process with sonicated and unsonicated AC particles obeyed pseudo first-order kinetics.     

Preparation and Faraday Effect of Fluoroaluminate Glasses Containing Divalent Europium Ions

Fluoroaluminate glasses containing various concentrations of Eu²⁺ were prepared under a reducing atmosphere for the present study, and the wavelength dependence of the Faraday rotation angle was examined. The magnitude of the Verdet constant (V_c) increased as the concentration of Eu²⁺ increased. In addition, the Verdet constant of glasses containing 5 cat.% Eu²⁺ was larger than that of fluoroaluminate glasses containing the same concentration of Tb³⁺ in the wavelength region from 400 to 600 nm. The effective transition wavelength, λ_t, for glasses containing Eu²+ as well as those containing Tb³+ was evaluated based on the Van Vleck and Hebb theory. Factors dominating the Verdet constant of those glasses are discussed in this report.     

溶剂热法制备铜氧化物的研究

采用CuCl2为前驱体利用溶剂热法制备纳米铜氧化物,井借助XRD和SEM等技术考察了反应温度和反应时间等条件对铜氧化物还原产物成分的影响.实验结果显示,反应温度对产物的组成具有直接的影响作用,反应时间的影响则是建立在反应温度基础之上的,当达到临界反应温度时延长反应温度可以得到纯净的铜氧化物,如果没有达到临界点时,即使延长反应时间也无法得到纯净的铜氧化物.