PRODUCTION OF GRANULAR AMMONIUM SULFATE

• Main Authors: OGAWA SHIGENORI, AKIYAMA NAOYUKI, ITO TADASHI, NAKAMURA TAIZO
• Format: Patent
• Language: English
• Published: 09.05.1988
• Subjects: AMMONIA; CHEMISTRY; COMPOUNDS THEREOF; CYANOGEN; INORGANIC CHEMISTRY; METALLURGY

PURPOSE:To efficiently obtain granular ammonium sulfate having excellent hardness and shape as well as a large grain size, by concentrating and crystallizing an ammonium sulfate solution under specific condition. CONSTITUTION:Ammonium sulfate, having a small grain size and obtained by absorbing NH3 in a coke oven in sulfuric acid, etc., is dissolved in water to c concentration close to the saturation value is charged into a crystallization vessel, e.g. continuous mixing crystallization type, etc., and a habit modifier, e.g. sulfamic acid, ammonium nitrate, etc., is added to give 1-10wt% concentration. The resultant solution is adjusted to pH 3.0-5.0 and 150-500wt% iron ion concentration and concentrated while stirring to operate the crystallization vessel under condition of 10-50wt% slurry concentration, 3-10hr slurry residence time and >50 deg.C under reduced pressure to afford the aimed hard and rounded granular ammonium sulfate having a large grain size.