Waste Pickling Liquor is produced when acid is used to remove scale from steel products. Typically it contains 10% acid and 5% iron in the form of the ferrous salt of the acid. It is produced in large quantities. Its disposal is difficult and will become more so when the planned total ban on deposition of liquids in land disposal sites becomes effective. An electrolytic process will be studied which will remove the iron from the Pickling liquor as a harmless solid, hydrated ferric oxide, and permit the recycling of essentially all the acid charged to the Pickling process. If successful, the electrolytic process will be used as the only means of recovery when the production of Pickling liquor is relatively small. For larger operations it might be preceded by an evaporation or freezing process which separates the unused acid from the iron salt. The proposed process will then convert the hazardous and corrosive iron salt to a harmless solid, hydrated ferric hydroxide, and recover the acid which had been used to form the salt.
