| Résumé : |
A direct liquor chrome recycling system has been successful operating at a South African wet blue tannery for approximately 4 years. For this period, excess chrome liquors (chrome wash liquors, sammying liquors and excess chrome recycle liquors) were discharged into the effluent treatment plant. This paper describes the incorporation of a plant for chrome recovery from these liquors by precipitation, settling out of the chrome sludge, and subsequent re-solubilisation of the chrome in the sludge by acidification.
The supernatant, containing very low concentrations of chrome, replaces the excess chrome liquors that were previously discharged to effluent, thereby reducing the chrome content in the effluent to an absolute minimum. (The supernatant entering the effluent contains <100mg/l Cr2O3). The chromium in the mixed effluent was reduced from 508 mg/l to 54mg/l Cr2O3 on average, after installation of the recovery plant.
The large scale implementation of this system is described, together with the economic and ecological advantages. Approximate net savings, excluding labor and electrical costs, amounted to R206 per day or batch of 1000 hides processed to the wet-blue. This amounts to an annual saving of R51700. At 251working days per annum. (R100 = $49.10 U.S.) |
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Ajouter le résultat dans votre panier Affiner la rechercheAn investigation into differences in properties of leathers produced from chrome recycling and conventional chrome tannage in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 73 (Année 1989)
