| 摘要 |
<p>High alumina cement is obtained by grinding a non-glassy high alumina phosphorus furnace slag containing combined aluminium and calcium (calculated as the weight ratio of alumina to lime) of 0.50 to 1.85:1 and combined silicon (calculated as silica) not exceeding 10% by weight, and treating with carbon dioxide to increase the setting time to at least 1.5 hours. The slag may be ground in an atmosphere of carbon dioxide or tumbled or fluidized with carbon dioxide after grinding. Carbon dioxide contact times of 0.5-1.5 hours are specified. The treatment may be carried out in the presence of water, e.g. moist carbon dioxide may be employed. The cement may be stored for 6-12 hours in an atmosphere of carbon dioxide after the above treatment. Specifications 747,016, 889,263 and 919,322 are referred to.</p> |
