选磷厂废水电化学处理循环利用

简要介绍磷矿浮选厂废水（尾矿水）进行电化学处理的研究和处理后循环使用的浮选工艺试验以及含固废水电化学处理的理论基础。试验结果表明：经电化学处理后的废水达到工艺用水水质控制指标；反复循环使用于浮选工艺取得满意效果；电化学处理方法是实现工业废水循环利用的有效手段。     

主分散剂加料顺序更迭的讨论

讨论了国内70 m3聚合釜等温水加料工艺传统的主分散剂加料顺序更迭的可行性,以及由此产生的对体系稳定性的影响程度和期望的PVC树脂在增塑剂吸收量等方面的有益变化。该技术在国内相关的生产领域将产生积极的作用,提高PVC树脂质量。     

Epitaxy growth and directed crystallization of high-density polyethylene in the oriented blends with isotactic polypropylene

Various lamellar orientations of high-density polyethylene (HDPE), due to competition between bulk nucleation and interfacial nucleation, have been realized in its melt drawn blends with isotactic polypropylene (iPP) upon cooling after subjected to 160 °C for 30 min. Directed crystallization, with heterogeneous nucleation in the bulk (within domains), is defined as lamellar growth along boundary of anisotropic domains and is favored in larger domains at higher temperature (slow cooling), since overgrowth of lamellae can feel the interface rather than impingement with neighbor ones as a result of scare nuclei at higher temperature. Moreover, lamellar growth caused by directed crystallization is dependent of dimension of confinement. Due to 2D confinement of cylindrical domains, lamellae can only grow along the axis of cylinder and thus b-axis orientation is formed. While in the layered domains with 1D confinement, however, lamellae grow with the normal of (110) plane along the melt drawn direction. On the other hand, epitaxial growth of HDPE chains onto iPP lamellae is related to the surface-induced crystallization and dominated by the interfacial nucleation. Only interfacial nucleation is preferred can epitaxial growth occur. Therefore, retarded crystallization, realized by either strong confinement in finer domains or rapid cooling or both, is favorable for it.     

TiCl4水解法制备纳米TiO2粉体

以TiCl4为原料,采用低温液相水解法制备了纳米TiO2粉体,着重研究了Ti4 的浓度和添加聚乙烯吡咯烷酮(Polyvinylpyrrolidone,PVP)对产物的晶相、颗粒大小和表面形貌的影响.使用XRD,TEM,SEM,激光粒度测试仪对样品进行了表征.结果表明,Ti4 浓度影响TiO2粉体的相转变温度,随着Ti4 浓度的升高金红石相的含量逐渐升高,但粉体分散性变差;添加PVP提高了所得TiO2粉体的分散性,粒径降低为40～50 nm左右,并改善了粉体的形貌.     

基于表面生物学改性的多孔状二氧化钛/磷灰石复合薄膜的制备

在钛合金表面采用微孤氧化得到一层多孔状的具有生物活性的二氧化钛，经随后水热处理可形成羟基磷灰石薄膜，提高钛合金表面的生物学性能，用SEM、XRD、EDX分析了薄膜的组织、结构和化学组成，同时考察了微弧氧化得到的二氧化钛膜的生物活性，结果表明，在室温条件下从含钙、磷离子的电解液中在钛合金基体上微弧氧化得到一层二氧化钛薄膜，蒸汽处理后得到具有生物活性的二氧化钛/羟基磷灰石复合薄膜，该膜多孔均匀，且生物活性高，有利于骨组织的吸附和生长。     

CO2 Hydrogenation to Methanol Over Cu/ZnO/Al2O3 Catalysts Prepared by a Novel Gel-Network-Coprecipitation Method

A novel gel-network-coprecipitation process has been developed to prepare ultrafine Cu/ZnO/Al₂O₃ catalysts for methanol synthesis from CO₂ hydrogenation. It is demonstrated that the gel-network-coprecipitation method can allow the preparation of the ultrafine Cu/ZnO/Al₂O₃ catalysts by homogeneous coprecipitation of the metal nitrate salts in the gel network formed by gelatin solution, which makes the metallic copper in the reduced catalyst exist in much smaller crystallite size and exhibit a much higher metallic copper-specific surface area. The effect of the gel concentration of gelatin on the structure, morphology and catalytic properties of the Cu/ZnO/Al₂O₃ catalysts for methanol synthesis from hydrogenation of carbon dioxide was investigated. The Cu/ZnO/Al₂O₃ catalysts prepared by the gel-network-coprecipitation method exhibit a high catalytic activity and selectivity in CO₂ hydrogenation to methanol.     

Using Dynamic Optimization Technique to Study the Operation of Batch Reactors

How to apply the global optimization technique, simulated annealing, and to explore the operation of batch reactors is addressed in this study. Based on the operating purposes and the imposed constraints, the batch reactor operations are first formulated as two optimal control problems: the maximal yield (or conversion) problem and the minimal operating time problem. The problems are then converted into non‐linear programming problems by the concept of control vector parameterization. The converted problems are solved by the algorithm derived from simulated annealing to determine the optimal operating policy and the performance index. These results are useful in assessing design and operation of batch reactors. In this article, the CSTR model is used to demonstrate the convenience and robustness of the proposed algorithm. Two typical reaction models are used to discuss the operations based on the optimal solutions.     

端氨基聚脲聚氨酯环氧树脂体系的固化反应及粘接性能

本文采用DTA和FT-IR研究了端氨基聚脲聚氨酯固化环氧树脂的反应特性,考察了被粘表面状态、偶联剂和促进剂、填料等对剪切强度性能的影响。并对该粘合剂耐化学腐蚀性进行了试验,说明具有好的耐腐蚀性。     

Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Ultrasonic Loop Airlift Reactor

The promoting effect of ultrasonic wave on the hydrodynamics and mass transfer characteristics of the loop airlift reactor was studied. The gas holdup, liquid circulation velocity, mixing time and overall volumetric mass transfer coefficient were examined and compared, with and without ultrasonic wave in the reactor. The experimental results show that ultrasound has almost no notable effect on the gas holdup, but has a tendency to decrease gradually the liquid circulation velocity and increase the overall volumetric mass transfer coefficient; and the effect on the mixing time is relatively complex. At low superficial gas velocity, the low powered ultrasound promotes the radial mixing of fluid; with the ultrasonic power increasing, ultrasonic vibration obstructs the axial mixing of fluid. Moreover, the effect of ultrasonic wave on the mixing time gradually decreases with the increase in the superficial gas velocity. Therefore there exists an optimal ultrasonic power for hydrodynamics and mass transfer. Correlations were also proposed for the hydrodynamics and mass transfer characteristics of the reactor.     

Mechanical properties and morphological structures relationship of blends based on sulfated EPDM ionomer and polypropylene

The mechanical properties and morphological structures of blends based on Zn²⁺ neutralized low degree sulfated ethylene propylene diene monomer rubber (Zn–SEPDM) ionomer and polypropylene (PP) were studied. It was found that Zn²⁺ neutralized low degree sulfated EPDM ionomer and PP blends, which are new thermoplastic elastomeric materials, have better mechanical properties than those of PP/EPDM blend. Theoretical analysis of tensile data suggests that there is an increase of the extent of interaction between PP and EPDM in the presence of a low degree of Zn²⁺, which is also an indicator of better interfacial adhesion between PP and Zn–SEPDM than that between PP and EPDM. SEM results proved that the finer dispersed phase sizes and the shorter interparticle distances are the main reasons for the improved mechanical properties of the PP/EPDM blend. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1504–1510, 2004