Recovery and Re-Use of Trivalent Chromium in the Leather Tanning Industry. Compendium on Low- and Non-Waste Technology

摘要

The company removes trivalent chromium from the effluent and re-uses it in the tanning process. The mean concentration of chromium (III) in the effluent is 5 kg/per cu m. This effluent is treated with MgO, producing a fast-settling and compact precipitate, Cr(OH)3. The chromium (III) concentration in the effluent is thus reduced to 2 gper cu m (a reduction of more than 99 percent). The Cr(OH)3 is then dissolved in sulfuric acid for re-use in the tanning process.