Synthesis,characterization and ion exchange properties of zirconium(IV) tungstoiodophosphate,a new cation exchanger

Zirconium(IV) tungstoiodophosphate has been synthesized under a variety of conditions. The most chemically and thermally stable sample is prepared by adding a mixture of aqueous solutions of 0·5 mol L⁻¹ sodium tungstate, potassium iodate and 1 mol L⁻¹ orthophosphoric acid to aqueous solution of 0·1 mol L⁻¹ zirconium(IV) oxychloride. Its ion exchange capacity for Na⁺ and K⁺ was found to be 2·20 and 2·35 meq g⁻¹ dry exchanger, respectively. The material has been characterized on the basis of chemical composition, pH titration, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The effect on the exchange capacity of drying the exchanger at different temperatures has been studied. The analytical importance of the material has been established by quantitative separation of Pb²⁺ from other metal ions.     

负载化非茂单活性中心催化剂乙烯聚合的研究

在硅胶上负载了双(N-环己基-3-叔丁基水杨醛亚胺基)二氯化锆配合物,得到负载化非茂单活性中心催化剂。该催化剂用于乙烯聚合,考察了配合物用量、共聚单体1-己烯用量、聚合温度、聚合压力、聚合时间、三乙基铝用量对乙烯聚合性能的影响及对聚合物的相对分子质量、相对分子质量分布、熔体流动指数和密度的影响。实验结果表明,负载化非茂单活性中心催化剂保持了原均相催化剂的乙烯聚合性能;该催化剂在淤浆聚合工艺中聚合平稳,所得聚合物的颗粒形态良好。     

用激光粒度分析仪测定二氧化锆粒度

介绍以六偏磷酸钠作为分散剂，采用激光粒度分析仪测量二氧化锆粒度的一种新方法。该方法的测量范围为0．05～300μm。     

B2O3/TiO2-ZrO2催化剂上环己酮肟的气相Beckmann重排反应

用共沉淀法制备了TiO2-ZrO2复合氧化物载体，BET，DTA，XRD表征结果表明，该复合载体具有较大的比表面和较好的热稳定性，对于环己酮肟气相Beckmann重排反应制己内酰胺，用复合载体制备的B2O3／TiO2-ZrO2催化剂，比分别以TiO2,ZrO2为载体所制备的B2O3/TiO2和B2O3／ZrO2催化剂具有更高的活性和选择性，实验表明，催化剂表面中等强度的酸位是环己酮肟气相Beckmann重排反应的有效活性中心。     

含Zr低合金高强度钢中夹杂物的特性

用电子探针研究了含Zr低合金高强度钢中夹杂物的形貌、大小及分布等特性。结果表明 ,钢样中的夹杂物为圆形 ,呈分散分布 ,其组成系含ZrO2 的复合夹杂物 ,而且MnS依附此复合夹杂物成核和长大。钢中添加少量Zr可明显改善夹杂物形态和分布 ,从而改善钢的强度和韧性     

Zirconium-based intermetallics as heterogeneous catalysts for the fischer-tropsch reaction: I. Zr-Ni-Co catalysts

Alloys of the general formula Zr₅₀Ni_xCO_50-x, where 0 ≦x≧ 50, have been prepared and used in the temperature range 300–400°C, in the pressure range 1–9 barg in a microtubular reactor for the reaction of hydrogen with carbon monoxide to give hydrocarbons. The alloys or intermetallic materials were prepared by argon arc melting, powdered by hydrogen decrepitation and characterised by means of optical microscopy (metallography), scanning electron microscopy with surface analysis and magnetic susceptibility measurements. The selectivity towards higher hydrocarbons increased with (i) increase in the total pressure and (ii) decrease in hydrogen content of the feed gases. The kinetics were found to be of the form: where m = 1.0 ± 0.2 and n = 0. The apparent energy of activation (E_a) lay in the range of 80–130 kJ mole^?1 and there appeared to be a compensation effect between E_a and the pre-exponential factor A. The turnover numbers for the reaction exhibited an activity maximum for alloys of composition around Zr₅₀Ni₄₀Co₂₀ and Zr₅₀Ni₃₀Co₂₀. Magnetic susceptibility measurements indicated that alloys changed their nature from moderately paramagnetic to strongly paramagnetic or even ferromagnetic after use and this is attributed to the conversion of zirconium to zirconium oxide during reaction with the attendant production of free 3d-transition metals. Derived catalysts prepared by air treatment of the hydrogen-decrepitated intermetallics behaved almost identically to the latter materials and gave similar magnetic susceptibility values to used hydrided materials.     

Zirconium-Embedded Polyhedral Oligomeric Silsesquioxane Containing Phosphaphenanthrene-Substituent Group Used as Flame Retardants for Epoxy Resin Composites

A zirconium hybrid polyhedral oligomeric silsesquioxane derivative (Zr–POSS–bisDOPO) is synthesized by the corner-capping and Kabachnik–Fields reactions. It is characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR), and then used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) to endow epoxy resin (EP) with flame retardancy. The flame retardancy, thermal stability, and mechanical properties of the cured EP/Zr–POSS–bisDOPO composites are investigated. The results show that when Zr–POSS–bisDOPO is added by 5–7 wt%, the EP/Zr–POSS–bisDOPO composites pass the UL-94 V-0 rating test. In addition, they have a better flame-retardant effect than pure EP. The combination of Zr atom embedded in the Si O cubic cage and the two phosphaphenanthrene substituent groups in one corner of cubic cage is expected to realize the Zr/Si/P ternary intramolecular hybrid synergistic effect and achieve the possibility of dispersing metal–POSS cages at a sub-micrometer-scale level into polymer matrix. It also proves that Zr–POSS–bisDOPO produces phosphorus-containing free radicals and terminates the chain reactions in gas phase. Meanwhile the Si O Si and Zr O units are retained in the solid phase, which promote the char formation and enhance the flame retardancy. This kind of Zr-doped POSS will be helpful for developing the new metal–POSS hybrid flame-retardant and polymer composites.     

近2年我国锆铪及锆化学制品雕生产、贸易及研发概况

介绍了我国近2年来海绵锆、锆铪制品和锆化学品的生产、进出口概况,以及重要研发进展。我国工业级海绵锆产量从2003年的100t增加到2005年的174t,2005年的销售量达到150t;锆粉与锆-铝消气剂等年产量在10t左右;锆材和锆设备年产量在100t以上;锆化学制品品种有10余种,年产量已达到20×104t。锆砂的沸腾氯化工艺、锆铪的MIBK法分离工艺、以电熔ZrO2为原料制取粗ZrCl2工艺和Al-Y复合ZrO2粉的生产工艺等的研发工作,都取得了突破性进展。     

Monte-carlo modeling of grain growth in Zr equal channel angular pressed and recrystallized

Grain boundary character distribution in equal-channel-angular pressed Zr was studied. Using a die design of 90°/20° and an operation temperature of 350°C. The initial grain size of 20 μm was reduced to about 270 nm with 4 passes via route B_c. The grain growth kinetics of the recrystallized state was obtained by experiment and Monte-Carlo computer simulation, respectively, which showed good agreement. Based on kinetics and morphological characteristics, it was concluded that the grain coarsening mechanism was governed by normal grain growth. No sign of abnormal grain growth was detected either in the experiment or in simulation despite taking into consideration anisotropy in grain boundary energy as well as its mobility. This indicates that grain boundaries produced by severely deformed Zr are stable against explosive coarsening. The evolution characteristics of the microstructure in the present ECA pressed and recrystallized Zr differed from those of cold rolled Ti in that the grain boundary misorientation distribution and texture were rather stable during grain growth. Jointly Appointed by the Center for Advanced Aerospace Materials This article is based on a presentation made in the 2002 Korea-US symposium on the “Phase Transformations of Nano-Materials,” organized as a special program of the 2002 Annual Meeting of the Korean Institute of Metals and Materials, held at Yonsei University, Seoul, Korea on October 25–26, 2002.