Chromium Recovery from Tanning Wastes by Pyrolysis and Sulfuric Acid Leaching.
Porter-J Jr.; Lollar-R; Huber-CV; Devarenne-L
For Reference Only At Bureau Libraries :136 pages
A study was conducted to evaluate the feasibility of recovering chromium from pyrolyzed tanning wastes by sulfuric acid leaching and reusing the final product in the tanning industry. Separate batches of tannery waste treatment sludge and finished leather and blue leather scraps were pyrolyzed in a batch furnace under varying temperature and atmospheric conditions. A bench-scale leaching evaluation was then conducted on each batch of pyrolyzed material to determine chemical composition and screen various leaching alternatives that could be pursued on a pilot scale. Next, chromium liquors were produced in a pilot-scale recovery system by sulfuric acid leaching. A tannage evaluation of these liquors was conducted on calfskin and pigskin. An additional batch of blue leather scrap was pyrolyzed in a rotary hearth furance and leached on a bench scale to determine the effect a different pyrolysis process would have on chromium recovery. The tannage potential of this liquor was also evaluated on calfskin and pigskin. The results indicated that chromium could be recovered from pyrolyzed tanning wastes with sulfuric acid; however, tannage with the resultant liquors was not acceptable. Comparable tannage results were obtained with the extract from the rotary hearth char; however, chromium recovery from this was lower. An economic analysis of this recovery method shows that it is not feasible or practical.
CP; Final Contract Report;
For Reference Only At Bureau Libraries
Tanners' Council of America