| 摘要 |
<p>The invention relates to a process for preparing a Portland cement containing up to 2 ppm of hexavalent chromium. According to the invention, the process consists in additivating the cement with 0.2...0.5% of a composition resulting from grinding 50...70% tuff, diatomite or porcelanite, 30...50% ferrous sulphate, at a fineness expressed as a residue of about 3% on the sieve of 90μm.</p> |
