核用富集硼-10碳化硼的制备

Preparation of 10B-enriched boron carbide applied in nuclear industry

10B的热中子吸收截面大,因此富集硼-10碳化硼除具有良好的力学性能,优良的抗氧化、耐腐蚀性能外,还因具备更优越的热中子吸收特性,在核工业中有重要的应用。与天然丰度碳化硼的制备工艺不同,富集硼-10碳化硼的制备要以硼同位素分离后得到的富集硼-10三氟化硼为起始原料。本文归纳总结了由三氟化硼制备中间物质(硼酸、氧化硼、硼粉),再通过碳热还原法、镁热还原法、直接合成法、有机溶胶-凝胶法制备碳化硼的多条路线。通过对以上路线的分析比较,进一步提出了以硼酸三甲酯、三烷基硼、硼烷作为中间物质,直接裂解制备碳化硼的3条新路线。基于国内外研究现状,判断了这3条路线的可行性,总结分析了其各自的优缺点,初步探究了由富集硼-10三氟化硼到富集硼-10碳化硼高效、经济的制备方法 。

Boron-10 has a large thermal neutron absorption cross-section, lherelore, boron-It）carbide （l0B4C） has some important applications in nuclear industry because of its goodmechanical properties, excellent oxidation, corrosion resistances and more superior thermalneutron absorption characteristics. Unlike the natural abundance boron carbide （B4C）, thepreparation of 10 B4 C takes the boron-10trifluoride （I^BF3） obtained by boron isotope separation asthe starting material. This paper summarizes a number of process routes for preparation ofintermediate material （boric acid, boron oxide, boron powders） from boron trifluoride and thepreparation of boron carbide through the carbothermic reduction, organic sol-gel,magnesiothermic reduction and direct synthesis. By analyzing the characteristics of the routesmentioned above, it is suggested that three routes of boron carbide prepared by direct cracking oftrimethyl borate, trialkyl boron and borane. Last, the paper analyzes and compares thecharacteristics and research progress of these three direct pyrolysis routes, discusses the efficientand economical preparation routes of boron-10 carbide.