| 摘要 |
The method of removing chromium from solid tanning wastes comprises an alkaline and an acidic phase. In the course of the alkaline phase, the tanning wastes are subjected to alkaline solution containing hydroxides of alkaline metals or metals of alkaline earths, carbonates, ammonia and ammonia salt, during at least 4 hours at the temperature up to 50 øC. After the alkaline treatment, chromium is removed from the solid tanning wastes through extraction of Cr3+ from collagen structure by means of adding of inorganic acid and salt, during at least 2 hours in course of the acidic phase. Soluble chromic salt is then separated from collagen and the chromium-free collagen is dehydrated. |
