机械力固相化学反应法制备纳米氧化铈粉末

以混合稀土为原料,采用机械力固相化学反应首先制备出前驱体,用DTA-TG分析前驱体的热分解温度,然后将前驱物热分解2.5h,得到二氧化铈粉体,用XRD、SEM和TEM进行表征。结果表明获得了平均粒径在小于100nm、分布均匀的纳米CeO3。     

超细粉末的机械固相化学反应合成

对超细粉末的特征和制备方法作了简要介绍,讨论了低热固相化学反应的特点和研究现状,重点阐述了机械化学和低热固相化学反应在合成超细粉末领域中的重要作用和取得的新进展,指出了今后的研究工作重点。     

机械力固相化学反应法制备纳米氧化铈粉末

以氯化铈为原料,采用机械力固相化学反应首先制备出前驱体,用DTA-TG分析前驱体的热分解温度,然后将前驱物热分解2.5h,得到二氧化铈粉体,用XRD、SEM和TEM进行表征。结果表明获得了平均粒径小于100nm、分布均匀的纳米CeO2。     

湿固相机械化学法制备超细氧化钇的研究

以工业上常见的水合草酸钇和氨水为原料，采用湿固相机械化学法制备了D50〈0．5μm，D50〈μm的窄分布超细氧化钇，研究了在球磨和煅烧过程中对氧化钇粒度的影响因素，通过粉末X射线衍射（XRD）、同步热分析（TG-DSC）和傅立叶变换红外光谱（FTIR）考察了球磨过程中的机械化学反应与物相转变，以及前驱体的热分解过程。     

湿固相机械法制备氧化铈抛光粉

以大比重碱式碳酸铈为前驱体,通过搅拌球磨和煅烧来制备氧化铈抛光粉。首先用正交试验法研究了球磨时间、球料比、液固比等因素对球磨产物的粒径及分布的影响,确定了影响产物粒径大小的因素排序是球料比球磨时间液固比,最佳球磨条件为液固比1∶1,球料比7.5∶1和球磨时间5 h。在不同温度下对最优条件下所得球磨产物煅烧制备了氧化铈,评价了它们的抛光性能与其形貌、粒径大小及分布、Zeta电位的关系。证明800℃和900℃煅烧所得氧化铈粒径小、粒度分布窄、Zeta电位为负值,随着煅烧温度的进一步升高,颗粒急剧增大,Zeta电位绝对值减小。对K9玻璃的抛光速率随煅烧温度升高先增大而后降低,在900℃时呈最大值,材料去除速率(MRR)达342.31 nm/min,抛光表面的均方根(RMS)粗糙度为0.286 nm。此时的氧化铈颗粒为类球形,SEM观察的一次粒子平均粒径为114 nm。     

用喷雾反应法制备实心球形氧化铈超细粉末

针对喷雾热分解法制备的粉体含有个别空心粒子和破裂球壳,本文采用喷雾反应法获得了实心球形氧化铈。此方法在传统的喷雾热分解基础上引入水蒸气来提高液滴温度并延缓液滴的蒸发,同时在前驱体中引入草酸二甲酯为水解剂。随着液滴温度的不断增高,草酸二甲酯水解为草酸并与铈离子发生沉淀反应,从而在液滴内形成体相成核。此时的液滴经干燥、煅烧最后获得实心球形氧化铈超细粉末。     

超细氧化铈提高聚氨酯耐热性能研究

采用一步法合成聚氨酯,控制超细氧化铈的加入比例,用热重法和机械性能测试分析了聚氨酯的热稳定性和机械性能.结果显示,与普通聚氨酯相比,加入超细氧化铈后聚氨酯的耐热性能明显提高.     

以碳酸铈为前驱体制备超细氧化铈及其抛光性能

研究了以水合碳酸铈为前驱体,采用直接球磨和煅烧的方法制备了中位粒径小于3μm的超细氧化铈。结果表明:所得产物均具有立方萤石型结构,随着煅烧温度的升高,产物粒径呈下降趋势,粒度分布也越来越窄,结晶度提高。但对三种不同玻璃的抛光能力均在900℃~1000℃之间呈现出极大值。因此认为抛光过程中玻璃表面物质的去除速率受抛光粉粒度、结晶度和表面活性的影响较大。     

流化床气流磨制备超细氧化铈粉末

采用LNJ-60型流化床气流磨在干法状态下制备超细氧化铈,考察了喷嘴间加速距离、粉碎压力和分级机转速等不同工艺参数条件下氧化铈粒度和产量的变化情况,得出了LNJ-60型流化床气流磨制备粒度在1～5μm范围内的超细氧化铈的理想工艺参数.     

Preparation of Compound Ultrafine CeO2 by Wet-Solid-Phase Mechanochemical Modification

To satisfy practical requirements from industrial applications, an alternate route for synthesis compound ultrafine CeO2 powders by wet-solid-phase mechanochemical modification using industrial grade hydrated cerium carbonate as raw material was proposed.The effect of modifier reaction percentage, reaction time, calcining temperature and modifier amount on particle size, density, suspensibility, and hardness of compound CeO2 powder was investigated.The phase evolutions of preparation process were characterized by XRD.SEM micrograph of the final product shows that compound CeO2 powders obtained are well-dispersed, spherically-shaped, uniformly-sized and submicron-sized particles.The method is readily available in raw material, low in cost, simple in process, and has great potential for industrialization.The compound CeO2 powders of different physical properties can be synthesized by controlling the above-mentioned influence factors in preparation process.     

高松装比氧化铈的制备

对制备氧化铈沉淀剂的选择,沉淀因素影响及煅烧条件等工艺进行优化选择。试验证明：该工艺能生产出高松装比产品。     

碳酸氢铵沉淀制备高松装密度氧化铈

研究了通过CeCl3与NH4HCO3共沉淀制备Ce2（CO3）3前驱体,Ce2（CO3）,经高温焙烧得到高松装密度CeO2。并对工艺的实施方法,流程控制及生产效果进行了阐述,结果表明：该工艺成本低、简单可靠、环境污染小,CeO2的松比可以提高到1．94-2．10g／cm^2;具有较高的经济效益。     

Effect of Surface Modification on Behaviors of Cerium Oxide Nanopowders

Study was made on the effect of surface modification on the behaviors of cerium oxide nanopowders.A surfactant-sodium dodecyl sulfate（C12H25SO4Na）was used to modify the surface of CeO2 powder particles.The unmodified and modified CeO2 powders were characterized by using a powder comprehensive characteristic tester,laser particle size analyzer,specific surface area tester,X-ray diffraction tester,and a scanning electron microscope.The testing and analysis results showed that C12H25SO4Na surface modification might increase the flowability and dispersity,and decrease the specific surface area and agglomeration of CeO2 powders.The mechanism of the surface modification of CeO2 powder particles was also discussed.     

Preparation of Well Dispersed and Ultra-Fine Ce （Zr）O2 Mixed Oxide by Mechanochemical Processing

Ultra-fine CeO2-ZrO2 mixed oxide was successfully synthesized by wet-solid phase mechanochemical processing, Ce2(CO3)3·8H2O, ZrOCl2·xH2O and ammonia were used as reactants. It is found that the crystalline Ce2(CO3)3·8H2O and ZrOCl2·xH2O are changed to amorphous cerium and zirconium hydroxide precursor after milling with ammonia, and Ce0.15Zr0.85O2 mixed oxide with pure tetragonal phase structure and medium particle size(D50)less than 1μm is formed by calcining precursor over 673 K. The XRD patterns indicate that the crystal unite size increases with rising calcining temperature due to crystal growth. However, the particle size and BET surface area of the Ce(Zr)O2 mixed oxide decreases with rising calcining temperature, which may be attributed to the contract of particles and the vanish of holes inside grains.     

碳铵沉淀法制备纳米氧化铈的研究

采用碳铵沉淀工艺进行了纳米氧化铈制备的研究,探讨了表面活性剂的加入量对氧化铈颗粒大小的影响,随着表面活性剂量的增加氧化铈颗粒粒径减小;煅烧温度对氧化铈粉末性能影响较大,随着煅烧温度的升高氧化铈粉末的晶粒尺寸增大,比表面积减小,煅烧温度为450℃时就已经形成了立方相的氧化铈。优化工艺条件制备出了单一粒径小于50nm、团聚体粒度重量累积中值粒径D50<150nm,粉末比表面积大于15m2/g,粉末的团聚常数(D50/DBET)小于6,形状为球形的纳米氧化铈粉末。     

Determination of Impurity Elements in Pure Cerium Oxide Product

Determination of the rare earth impurity in pure cerium oxide is done by ICP-MS.The interference and other factors which affect analytical results were discussed.The accuracy are between 0.81% ～ 11.98% and the recoveries of standard addition are 96% ～ 112.5%.This method can meet the demand for product inspection.     

Mechanochemical Reaction of Lanthanum Carbonate with Sodium Hydroxide and Preparation of Lanthanum Oxide Nanoparticle

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X射线荧光光谱法分析喷煤添加剂中氧化铈含量

采用X射线荧光光谱仪分析喷煤添加剂中的氧化铈含量,以高炉渣标样为基体,与高纯氧化铈混合,制备出一系列标准样品作为校准样品,建立适于喷煤添加剂中氧化铈含量的分析曲线。喷煤添加剂经过高温灼烧,硝酸锂做氧化剂,用四硼酸锂做熔剂,熔融制样。该方法分析速度快,分析精密度高,通过加标实验,回收率为95%~105%,分析结果准确度高,能够满足生产需求。