1. Physical properties: Molecular formula: (NH4)2SO4 is colorless crystals or white particles and decomposes above 280℃. The molecular weight is 132.14 and the specific gravity is 1.77. It can be prepared by the direct reaction of ammonia and sulfuric acid, but it is mainly produced by recycling by-products of industrial production or waste gas and liquid. 

2. Packaging method: woven bag, lined with plastic film.