Ammonium sulfate chemical formula (NH4)2SO4, referred to as ammonium sulfide. Colorless rhombic crystal, density 1.769g/cm3(20℃), melting point 146.9℃, easily soluble in water, solubility of 70.6g/100ml(0℃), the solution is acidic; When closed heating, the melting point is 513 ° C, and when open heating to 100 ° C, it begins to decompose into acid ammonium sulfate. Ammonium sulfate is the main product of nitrogen fertilizer industry and one of the gas purification products of coke oven in coke plant. It is a traditional production method of coke plant to recover ammonia from coke oven gas and make ammonium sulfate by saturator method. The product is powdery crystal, easy to caking. Since the 1960s, the coking plant has used pickling tower method to produce ammonium sulfate. The prepared ammonium sulfate is crystalline in large particles and is not easy to caking.