Improvement of Ammonium Sulfate Crystal habit by Admixtures

Abstract

One of the most urgent tasks facing in the coke and by-product industry is improvement of the crystalline ammonium sulfate. It has been desirable that the crystal morphology of ammonium sulfate is cubic-like, rice grain-like or sphere form. A method was developed for the granulation of ammoniu m sulfate crystal by using some admixtures. The effect of admixtures (31 compounds) were examined by determining the crystal form. The effective admixtures are summerized as follows. (1) Reducing agents: sulfides, dithionite, ascorbic acid, etc. ( 2 ) Chelating agents: ethylenediaminetetraacetic acid (E DTA), nitrilotriacetic acid, polyphosphates, oxalic acid, etc. ( 3 ) Compounds, which m ake double salt combined with ammonium sulfate: amidosulfuric acid. It was found that the combination of amidosulfuric acid with reducing agents or with chelating agents are very effective for granulation and production of cubic-like ammonium sulfate crystal.