Experience in industrial practice of enzymatic dechromation of chrome shavings

A modification of the ERRC process for enzymatically treating chrome shavin gs was put into practice with a daily capacity of 3 metric tons. This proce ss uses low-molecular weight organic amines to replace the relatively expen sive magnesia. This modification increases the yield of soluble protein wit h a relatively low ash content and of a filter cake containing more chromic oxide, both of which offer easier and cheaper processing. We devoted consi derable attention to potential commercial applications of end products. Suc cessful commercial applications for the hydrolyzate include use as an organ ic nitrogenous fertilizer or fertilizer component, and use in the manufactu re of biodegradable polymers for agriculture sowing tapes. Potential applic ations include use in the production of inexpensive formaldehyde-free adhes ives; as anti-skid agents in PVC and rubber compounds; as agents for increa sing adhesion to textile backing in conveyor belt manufacture; as heat stab ilizers in PVC paste; and as an additive to concrete and plaster to influen ce setting time, rheological properties, and the energy demands of raw mate rial grinding. Recovered chromic salts were successfully used to tan hides on a pilot-plant scale. Because of unbalanced demands for chrome tanning sa lts in the Czech Republic, we investigated other uses of chrome sludges. Po tential applications included chromic pigments for glassmaking, manufacture of heat-resistant bricks, and the liquid oxidation of chrome sludges to pr oduce a high quality, commercially attractive alkaline chromate. With a vie w to further applications for chrome sludges, we studied methods of deprote ination. Results from the industrial scale enzymatic dechroming process, pr otein hydrolyzate applications, and treatment and utilization of chrome slu dges are presented.