| 摘要 |
<p>Grinding of a brittle substance at a cryogenic temp. is effected with an inert liquefied gas by (a) subjecting the substance to a first cooling with vapour from the liquefied gas, (b) subjecting to a second cooling with the liquefied gas, to a temp. at which the substance is brittle throughout its mass, and (c) grinding the substance in contact with the liquefied gas, all the vapour provided by the vaporisation of the liquid gas during the second cooling and during the grinding passing into the grinder. For grinding rubbers, plastics and food materials to powder.</p> |
