| 摘要 |
<p>534,731. Puzzuolanic materials. MITCHELL, F. G., and TEMPLE, J. E. Sept. 13, 1939, No. 25769. [Class 22] The puzzuolanic activity of the fine ash from carbonaceous fuels is increased for use with cement by hydrating and then dehydrating. Particles of carbon are removed from the ash by a fine mesh screen and iron oxide by magnetic separation, allowing the dust to fall freely through air in a non-uniform magnetic field. The dust is then hydrated by treatment with saturated steam at moderate pressure and dehydrated by treatment with superheated steam or other dry gas at a temperature of not less than 150‹ C.</p> |
