| 摘要 |
<p>1418146 Natural gypsum hemihydrate STAMICARBON BV 9 April 1973 [7 April 1972] 16938/73 Heading C1H The water resistance of natural hemihydrate gypsum is improved by forming a mixture of the gypsum, water and a blast-furnace slag with a Blaine value of at least 2000 obtained by rapid cooling to form granules and/or wet grinding, the pH of the mixture being controlled at between 11 and 12. The blast furnace slag is present in an amount of not more than 40 wt. per cent based on the calcium sulphate hemihydrate present. The examples illustrate the addition of 15 wt. per cent dry ground rapidly cooled granulated blast furnace slag and of 15 wt. per cent wet-ground granulated slag. Cement may be added to control the pH.</p> |
