Deliming operations of cattle hides usually last 2 hours and are generally associated with the alkaline phase of beamhouse operations. The progress of deliming in pelts is monitored by the checking of pH values of process liquors and in the cutting of a pelt cross-section. Phenolphthalein is used to monitor deliming pelt cross-sectional progress.
The ammonium ion is then free to penetrate the pelt cross-section and further ionise to act as an acid:
Other weak acids can be used such as boric acid. acetic, formic, lactic acid and carbonic acid. Carbonic acid is used in a deliming process called carbon dioxide deliming. Strong acids such as hydrochloric acid and sulfuric acid can also be used but their use is limited.
Wipo Publishes Patent of Rong Zheng, Liming Zhao, Xizhi Fan, Jing Li and Lanxess (Changzhou) for "Ammonium-Free Deliming Agent and Use Thereof in Leather Deliming Processes" (Chinese Inventors)
Jul 26, 2013; GENEVA, July 26 -- Publication No. WO/2013/107233 was published on July 25.Title of the invention: "AMMONIUM-FREE Deliming...