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安徽工业大学 毕业设计(论文)报告纸
LiBH4制备工艺的研究
摘 要
本文通过气-固反应法研究了LiBH4的制备工艺。在试验中，研究了LiBO2?8H2O的干燥工艺；分析了球磨对LiBO2+Mg混合物反应的影响；同时还研究了温度和压力对球磨产物氢化时的影响。从结果中发现，LiBO2?8H2O最佳干燥工艺为：先在170 ℃时干燥2小时，然后在650 ℃下干燥3小时。LiBO2+Mg在氢气气氛下球磨50小时后的产物为MgH2+非晶相LiBO2，同时还剩有部分未反应的Mg。在氢气气氛下球磨50小时后的产物经200~290 ℃氢化处理(氢气压力5 MPa)24小时后的产物比较复杂，但并不能得到LiBH4。但该球磨产物在250 ℃、7 MPa下氢化处理36小时后可以得到LiBH4。
关键词：氢化物 合成 晶体结构
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安徽工业大学 毕业设计(论文)报告纸
Study on preparation process of LiBH4
Abstract
LiBH4 was prepared successfully by Gas-Solid reaction of LiBO2+Mg+H2 in this work. The drying process of LiBO2?8H2O was investigated at first. The effects of ball milling on the reaction of the LiBO2+Mg mixture were then analyzed. Finally, the effects of hydrogenation pressure and temperature on the reaction products were studied. It was found that the optimal drying process of LiBO2?8H2O was drying at 170 ℃ for 2 hours firstly and then drying at 650 ℃ for 3 hours. The ball milling products were MgH2 and the amorphous LiBO2 when the LiBO2+Mg mixture was milled for 50 hours under hydrogen atmosphere. However, a small amount of unreacted Mg existed after ball milling. The products was complicated when the ball milled product was hydrogenated at 200~290 ℃ for 24 hours under a hydrogen pressure of 5 MPa. However, LiBH4 can be obtained by the hydrogenation of the ball milled product at 250 ℃ for 36 hours under a hydrogen pressure of 7 MPa. Key Words：Hydride Synthesis Crystal structure
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安徽工业大学 毕业设计(论文)报告纸
目 录
引 言 .................................................................................................................................. 1 1. 文献综述 ............................................................................................................................. 2
1.1 氢能源 ........................................................................................................................ 2 1.2 氢能源的储存材料----金属氢化物 ......................................................................... 2 1.3 硼氢化物的结构、性质和应用 .............................................................................. 4
1.3.1 硼氢化物的结构 ............................................................................................ 4 1.3.2 硼氢化物的物理化学性质 ............................................................................ 5 1.3.3 硼氢化物的应用及水解制氢........................................................................ 6 1.4 硼氢化物的合成方法 ............................................................................................... 7
1.4.1 硼氢化锂的制备 ............................................................................................ 7 1.4.2 其他硼氢化物(硼氢化钠)的制备 ............................................................... 10 1.5 本文的目的意义及研究内容 ................................................................................ 19 2. 实验方法 ........................................................................................................................... 19
2.1 实验药品和仪器 ..................................................................................................... 19 2.2 实验方法.................................................................................................................. 20
2.2.1 无水LiBO2原料的制备 .............................................................................. 20 2.2.2 合金粉末的制备 .......................................................................................... 21 2.2.3 机械球磨 ....................................................................................................... 21 2.2.4 氢化反应 ....................................................................................................... 21 2.2.5 X射线衍射(XRD)分析 ................................................................................ 22
3. 实验结果及讨论 ............................................................................................................... 22
3.1 热力学判据和动力学判据的计算 ........................................................................ 22
3.1.1 热力学判据 ................................................................................................... 22 3.1.2 动力学判据 ................................................................................................... 24 3.2 无水LiBO2原料的制备 ........................................................................................ 25
3.2.1 LiBO2?8H2O的结构 ..................................................................................... 25 3.2.2 LiBO2?8H2O的脱水工艺 ............................................................................. 25
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安徽工业大学 毕业设计(论文)报告纸
3.3 机械球磨对LiBO2+Mg混合物反应的影响 ....................................................... 26
3.3.1 LiBO2+Mg混合物在不同气氛下球磨产物的X衍射图谱分析 ............ 26 3.3.2 氢气气氛下延长球磨时间对反应产物的影响 ........................................ 27 3.4 温度对LiBO2+Mg球磨产物氢化反应的影响 ................................................... 29 3.5 压力对LiBH4合成的影响 .................................................................................... 30 结 论 ................................................................................................................................. 32 致 谢 ................................................................................................................................ 33 参 考 文 献 .......................................................................................................................... 34 附 录 英文翻译 ...................................................................................................... 36
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