| 摘要 |
The invention relates to an additive for reducing hexavalent chromium in products such as, in particular, cement, slag or gypsum, that comprises a stabilised aqueous solution of a chromium reducing agent, containing: water; a chromium reducing agent such as heptahydrated ferrous sulphate; an acid; an oxygen reducing agent dissolved in excess in water. The solution may have a pH from 4 to 6. In order to improve the grinding, the additive may further include ethanolamine. The additive can be sprayed on cement during grinding, or added in a concrete mixer. |
