【作者】 王爱军；

【导师】 张辉；

【作者基本信息】 北京交通大学 ， 应用化学， 2010， 硕士

【摘要】 摘要：Al2O3材料具有高强度、高硬度、抗腐蚀、耐高温、抗氧化性等特性,A1203粉体是制备催化剂及其载体、牙科材料、特种陶瓷的重要原料。多孔A1203球形颗粒不仅可以作为优良的催化剂及其载体,应用于药物缓释／控释制剂,又因为颗粒为多孔结构,可以节省原材料,降低生产成本；此外,由于A1203颗粒为球形,其流动性和成型性好,这样制出的块体具有良好的致密性。本论文首次采用一种新颖的准气相反应法,制备出新颖的具有多孔结构的氧化铝球形颗粒。首先,以氯化铝溶液和高纯氨气为原料,合成多孔氧化铝前驱物球形颗粒,研究了AlC13溶液浓度、系统真空度、NH3气流量等因素对前驱物颗粒形貌、大小和显微结构的影响,获得了较佳的合成工艺条件：AICl3溶液浓度为25wt%、系统真空度为-0.01MPa、NH3气流量为50L／H。在较佳的合成工艺下,合成出的多孔氧化铝前驱物颗粒的平均粒径为6.705μm,标准偏差3.224μm,球形度良好,显微结构为实心结构和空心结构两种。其次,探讨了多孔氧化铝前驱物球的干燥制度和煅烧制度。研究了烘箱干燥、室温干燥和微波干燥三种干燥方式对前驱物球性能的影响，并研究了500℃、800℃、1000℃和1200℃煅烧温度下对氧化铝球性能的影响。研究表明：在较佳的合成条件下合成出的氧化铝前驱物球,经过微波“低火”干燥12min,1200℃煅烧2h后,得到的多孔氧化铝球的平均粒径为2.68μm,形貌为球形,晶型为单斜结构的α-Al2O3。最后,研究了在准气相反应合成过程中的收集瓶内和干燥过程中对团聚状态的控制,分别加入不同分子量、不同含量的聚乙二醇对颗粒团聚状态的影响。结果表明：在收集瓶中和干燥过程中,分别加入质量分数为1.0%的聚乙二醇6000可以有效地控制团聚的发生。因此,通过本课题的研究,采用准气相反应法能够制备出多孔氧化铝球形颗粒,其较佳工艺条件为：AICl3溶液浓度为25wt%、系统真空度为-0.01MPa、NH3气流量为50L／H,微波“低火”干燥12min,1200℃煅烧2h。制备出的多孔氧化铝颗粒的平均粒径为2.68μm,形貌为球形,分散性好,其晶型为单斜结构的α-Al2O3。更多还原

【Abstract】 Aluminia materials possess high strength and hardness, excellent corrosion, high temperature, oxidation resistances, and other characteristics. Aluminia powder is the raw materials of preparing Aluminia materials such as catalyst and its carrier, dental materials, special ceramics. Porous spherical Al2O3 particles not only serve as an excellent catalyst and its carrier, drug delivery/controlled release, but also can used less due to its low density, therefore lower production costs of Aluminia materials. Besides, spherical Al2O3 particles are favourable to forming of bulk Al2O3 densified. In this thesis, a novel quasi-gaseous state reaction method, for the first time, was used for preparation of a new porous alumina spherical particles.Firstly, porous alumina prescursor spherical particles were synthesized using aluminum chloride solution and high-purity ammonia gas as starting agents. Effects of AICl3 solution concentration, vacuum, and NH3 gas flow rate on precursor particle morphology, size and microstructure have been investigated, and optimum synthetic conditions have been attained:AICl3 solution concentration—25wt%, vacuum—-0.01MPa, NH3 gas flow—50L\h. Precursor particles synthesized with optimum synthetic conditions are:average size—6.705μm, standard deviation—3.224μm, well sphericity, solid or hollow microstructure.Secondly, the drying and calcination processes and the control of agglomeration were studied for alumina precursor spheres. Effects of dryings in the oven, at room temperature, and with microwave on the performance of the precursor have been investigated, also the effects of calcination temperatures at 500℃,800℃,1000℃and 1200℃on the performances of alumina spheres have been studied. The results show that a proper drying and calcining process for alumina precursor spheres synthesized by using optimum conditions is:first drying with microwave of "low fire" for 12 min., then calcining at 1200℃for 2h. Porous alumina particles, obtained through above drying and calcining processes, have the average diameter 2.68μm, spherical shape, solid and hollow microstructures, andα-Al2O3 crystalline type.Finally, effects of molecular weight and concentration of polyethylene glycol(PEG), added in collection bottle in quasi-gas reaction synthesis and drying process, repectively, on particle clusters have been investigated. The results show that for any one of two adding ways, using 3.0wt% of PEG 6000 can effectively prevent the clusters formation, and adding in drying process is better than doing in collection bottle.Therefore, porous alumina spherical particles can be prepared using quasi-gas reaction process, and a proper process is:AICl3 solution concentration—25wt%, vacuum—-0.01MPa, NH3 gas flow rate—50L\H, drying with "low fire" microwave for 12min., and calcining at 1200℃for 2h. The porous alumina spheres prepared by above process possess average size 2.68μm, spherical shape, well dispersion, solid and hollow microstructures, crystalline structure of the monoclinicα-Al2O3更多还原