| 摘要 |
Beryllium oxide of fine particle size e.g. of surface area 10-20 sq. m/g., is produced by evaporating by boiling an aqueous solution of beryllium sulphate to the point of crystallization and passing it immediately into a chilled and continuously cooled aqueous solution of an alcohol e.g. methanol or ethanol. Crystals of the beryllium sulphate tetrahydrate are thus precipitated, which are separated and heated in vacuo to a temperature sufficient to drive off only two molecules of water of crystallization e.g. 100-200 DEG C. for up to 12 hours to form the dihydrate, which is then calcined in air (e.g. at 900-1100 DEG C.) to form the oxide. Sintered bodies of the oxide of bulk density at least 2.85 g/cc., suitable as sheathing for fissile material of nuclear fuel elements, may be made by mixing the oxide powder with a binder, granulating the mixture and pressing to form green compacts which are then sintered in hydrogen. |
