| 摘要 |
Pure graphite blocks having a density of at least 1.9 gm./c.c are made by grinding synthetic graphite powder for at least 45 hours until substantially all the particles are less than 40 microns in diameter and at least 80% of them are less than 20 microns in diameter, leaching out impurities with HCl if necessary, and cold-compacting the powder at a pressure of at least 20 tons per square inch in a die or by hydrostatic pressure. The powder may be mixed with up to 50% by volume of fissile or fertile material in the form of metal, oxide, or carbide powder. Examples of the process are given. Specifications 833,647, 850,014 and 850,015 are referred to.ALSO:Graphite blocks of high density, i.e. 1,9 gm/c.c. or more, and high purity are made by grinding synthetic graphite powder for at least 45 hours until substantially all the particles are less than 40 microns in diameter and at least 80% of them are less than 20 microns in diameter, leaching out impurities with HCl if necessary, and cold-compacting the powder at a pressure of at least 20 tons per square inch in a die or by hydrostatic pressure. The powder may be mixed with up to 50% by volume of fissile or fertile material in the form of metal, oxide, or carbide powder. Examples of the process are given. Specifications 833,647, 850,014 and 850,015 are referred to.
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