| 摘要 |
<p>A dry cement composition containing an amount of ferrous sulphate (FS) for eliminating or substantially reducing the content of water-soluble chromate, is produced by grinding a starting material (C, G) in a cement mill, and the ground cement material is passed from the mill to a storage container (33). The ferrous sulphate in an amount of 0.01 - 10 and preferably 0.4 percent by weight is added to and mixed with the starting material in a dry or non-dissolved condition at a location or at locations upstreams of the storage conatiner (33). The ferrous sulphate is a particulate material, the particles of which are provided with an oxidation preventing coating. the ferrous sulphate is preferably added to the starting material upstream of the cement mill.</p> |
