| 摘要 |
<p>In a cement composed of calcium sulphate and other ingredients, the calcium sulphate is calcined at above 850 DEG C. but below such a temperature as causes decomposition-preferably between 900 and 1200 DEG C.-before being added to the other ingredients. The other ingredients may comprise Portland or aluminous cement, pozzalanas, limes and especially slags and slag cements. The sulphate and other ingredients may be ground together preferably in the presence of an agent assisting grinding such as coke. The proportion of sulphate may range from 3 to 5 per cent as for Portland and slag cements to 20 per cent or higher for the production of "supersulphated" slag cements.</p> |
