| 查看: 289 | 回复: 4 | |||
| 当前主题已经存档。 | |||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | |||
[交流]
求助翻译一段话
|
|||
|
Preparation of ceria with large particle size and high appearance density。Cerium is one of the most abundant rare earth elements in both bastnasite and monazite. Ceria has been widely used in optical, catalytic, electrolyte, and sensor materials, with unique performances. With the development of functional materials, great interest has been focused on the synthesis and characterization of specific fine/mesoporous ceria powder. In this study, the modified precipitation and recrystallization processes combined with a controlled calcination process for fabricating the ceria with large particle size and high appearance density was reported. Dunng precipitation, a certain amount of mineral acid such as nitric acid served as an additive, to adjust the precipitation and crystallization processes of cerium oxalates. An appropriate acidic condition could lead the process into the Oswald ripening stage and made the particles become bigger. Thus, the appearance density of powder was increased. The optimized conditions, such as the temperature, feeding speed. type and concentration of mineral acids, and the concentration of cerium-contained stock solution, were investigated and evaluated. Rare earth oxalate eluted or immersed with mineral acid could act as a precursor, to obtain an oxide with large particle size and high appearance density, by decomposition in controlled calcinations, in which the moisture must be gradually released first. The treatment of precipitates and the calcination process could affect the particle size distribution and appearance density. The optimized condition approached in this study is: (1) To increase the particle size and appearance density, the solution of nitric acid (5 mol/L) and oxalic acid (1 0 g/L) can be used as an eluent or immersing reagent. (2) The programmed calcination process is necessary, that is, heating the as-elutedhmmersed oxalates mildly from room temperature to 300℃at a heating rate of 5℃/min, and keeping the samples at 300 "C for 1 h; consecutively, heating to 900℃at 10℃/min, and then keeping for 4 h. After the above-mentioned optimization process, the particle size and appearance density of ceria could reach 20 pm and 1.9 g/cm3, respectively. This method could also be applied to prepare praseodymium oxides, however, it was not successful in preparing other light rare earth oxides. Compared with other processes, this study provided a facile strategy with low cost. |
回复此楼» 猜你喜欢
三无产品还有机会吗
已经有6人回复
-
垃圾破二本职称评审标准
已经有7人回复
-
投稿返修后收到这样的回复，还有希望吗
已经有7人回复
-
博士申请都是内定的吗？
已经有14人回复
-
谈谈两天一夜的“延安行”
已经有13人回复
-
氨基封端PDMS和HDI反应快速固化
已经有11人回复
-
之前让一硕士生水了7个发明专利，现在这7个获批发明专利的维护费可从哪儿支出哈？
已经有11人回复
-
论文投稿求助
已经有4人回复
-
Applied Surface Science 这个期刊。有哪位虫友投过的能把word模板发给我参考一下嘛
已经有3人回复
