Effects of Several Factors on Viscosity of Alumina-spinel Slurries

1IntroductionSpinelismorestablethanaluminainoxidation ,al kali,salt,fusedmetal,slagandcarbonatmosphere .Inrecentyears ,moreattentionhasbeengiventoit .Andithasbeenwidelyusedinthefieldofinsulated materials ,high performanceceramicsandrefractories .Concentratedalumina spinelslurrieswithgoodfluid ityarecrucialtopreparealumina spinelcastables .Whethertheconcentratedslurrycanbeobtainedornothastightrelationshiptoitsrheologicalbehavior .Ingener al ,therheologicalbehavioroftheslurryisaffectedbyanumber…     

高效分散剂对高性能陶瓷成型适用性研究

本文报道了多醚基的非离子表面活性剂(如JFC、PEG、PVA)、多羟基有(无)机高分子(如变性淀粉、羟丙基纤维素、CMC、(NaPO3)6、硅溶胶、四环素)和多羧基的高分子聚合物(如PAA、NH4PAA)等三类分散剂或其复合物对以水为分散介质的超细琢—A12O3等高性能陶瓷都具有良好的分散性和适用性。配制出高分散、高固相含量(>55%)、高均匀性(无团聚体)、低粘度、低触变形等成型性能良好的超细粉浆体;采用这种浆体进行传统的注浆成型工艺,就可制得相对密度在55%以上(高可达61vo1%)的高固相含量、微观结构均匀的无团聚的坯体。并指出:分散剂的链长、分子量、基团位置等在一定范围的调节,可改变分散剂在水中或吸附时的介电常数、折射率、紫外吸收频率等极化性质,以适应胶粒间排斥力占主导作用的需要,从而达到分散的目的。     

不同分散剂对纳米铁粉分散性能的影响

通过对直流氢电弧蒸发法制备的纳米铁粉Zeta电位的测量,选用非离子型和阴离子型2类分散剂,分别研究了油酸、聚乙烯吡咯烷酮（PVP）和十二烷基苯磺酸钠（SDBS）3种分散剂对纳米铁粉分散性能的影响.结果表明：超声时间、分散剂加入量及pH值对分散效果影响显著,随着超声时间和表面活性剂加入浓度的提高,粉体分散效果呈先增大后减小的趋势;PVP和油酸对纳米铁粉的分散效果较好,分散剂分散效果从高到低顺序依次为：PVP＞油酸＞SDBS;推荐最佳分散工艺：无水乙醇作为溶剂,超声功率560 W,超声时间15 min,pH等于10,PVP加入量4%.     

染料加工用新型分散剂的初步研究

选择三种表面活性剂组成的新型三元复合分散剂,将分散染料制备戍液状染料试样,并与相应的分散染料商品作对比进行各种染色试验,考察复合分散剂的应用性能。     

阳离子型高分子分散剂的制备及应用研究

通过自由基引发溶液聚合,以二甲基二烯丙基氯化铵（DMDAAC）为阳离子共聚单体,过硫酸钾（KPS）为引发剂,与羟乙基纤维素（HEC）共聚制得阳离子型高分子分散剂PHD,通过正交实验得到最优反应条件为：m（HEC）∶m（DMDAAC）=0.6∶10,引发剂w（KPS）=1%（以DMDAAC的质量计,以下同）,反应温度75℃,反应时间2h。用IR对产物进行了表征,将产品（PHD）应用到高岭土泥浆中,对其流动性能进行测试,并通过SEM对分散体系的微观形貌进行分析,结果表明,PHD对陶瓷用高岭土具有良好的分散效果。     

聚电解质分散剂对ZnO悬浮体流变性的影响

本文研究了聚电解质分散剂PMAA－NH_4对ZnO悬浮体流变性的影响。结果表明：pH在9~10.5,分散剂用量为0.2~0.3Wt％时,ZnO悬浮体粘度最低。此条件下,可制得固相量达43vol％（81wt％）、粘度仅为237mPa·S的稳定悬浮体。     

Preparation of dense 0.9Al2O3−0.1TiO2 ceramics with highly improved microwave dielectric properties by a noncontaminated DCC method

In this paper, dense 0.9Al₂O₃ ??0.1TiO₂ ceramics with highly improved microwave dielectric properties were prepared by a noncontaminated direct coagulation casting (DCC) method. The suspension was destabilized and coagulated by consumption of the dispersant without introducing impurity ions. The effect of dispersant content, pH value and solid loading on the rheological properties of 0.9Al₂O₃ ??0.1TiO₂ suspension was investigated. It was found that 0.9Al₂O₃ ??0.1TiO₂ suspension with a high solid loading of 50?vol% and low viscosity of 0.7?Pa?s could be prepared by adding 0.5?wt% TMAOH at the pH in the range of 10–12. The suspension was coagulated by adding 2?vol% GDA when it was treated at 60 ~ 80?°C for 40 ~ 60?min. Compared with dry pressing method, more homogeneous and denser microstructure could be obtained in 0.9A1₂O₃ ??0.1TiO₂ ceramics prepared by DCC via dispersant reaction which were sintered at 1550?°C for 3?h and annealed at 1100?°C for 5?h. The Al₂TiO₅ second phase in 0.9A1₂O₃ ??0.1TiO₂ ceramics prepared by DCC via dispersant reaction could be eliminated more easily by annealing treatment. After annealing treatment, only Al₂O₃ and TiO₂ phases could be detected. Therefore, higher density and much better microwave dielectric properties with ρ?=? 3.81?±?0.02?g/cm³, ε_r =?12.17?±?0.02, Q ×?f =?25,637?±?749?GHz, τ_f =?13.12?±?1.62?ppm/°C were obtained by DCC via dispersant reaction, and the Q ×?f value almost improved by 25%. Without introducing impurity ions, it provides a new insight into preparing complex shaped function ceramics with high properties.     

Morphology control of mesoporous Cu2O by reductants and its photocatalytic activity

Mesoporous Cu₂O particles with different morphologies were synthesized via simple one-pot reactions. Effects of reducing agents, dispersant, template, and temperature on the structure of the prepared materials were investigated. Mesoporous flower-shaped Cu₂O materials were obtained at 70 ℃ using glucose as a reductant. Different hollow microsphere shapes of Cu₂O could be prepared at 40 ℃ using another type of reductant, ascorbic acid. The results indicated that the uniform morphology of synthesized Cu₂O with mesopores presented a maximum specific surface area of 45.3 m²/g. Furthermore, the as-prepared Cu₂O particles showed good photodegradation efficiencies of methyl orange in the range of 86.0–93.7%, depending on their morphologies.     

Effect of colloidal agents in iron ore pelletizing

ABSTRACT

Organic binders have been used to replace bentonite in the pelletizing process of iron ore. In this research, colloidal agents were evaluated in a pelletizing process comparing their influence with the behavior of Peridur® and bentonite. Bench tests were carried out to identify the effects of binders and dispersant on the dispersion degree of mixtures, and their influence on the liberation/flocculation of fine particles. The results show that the dispersant acts on the fine particle content of the iron ore by removing ultrafine particles that are adhered to the surface of coarse particles, making the ultrafine available to the medium.     

纳米SnO2粉体团聚的控制

分析了纳米SnO2粉体团聚的形成机理,并从物理法和化学法两个方面分析归纳了控制纳米SnO2粉体团聚的方法。最后指出,在实际应用中应结合纳米SnO2粉体的使用形式,考虑其成本和可操作性等问题,综合采用多种方法控制纳米SnO2粉体团聚。