The core component of caprolactam-grade ammonium sulfate crystals is ammonium sulfate ((NH₄)₂SO₄). However, compared with other by-product ammonium sulfate grades such as coking-grade and power plant-grade, its most prominent features are high purity and low impurities. The specific property parameters are as follows:
The nitrogen content is stably maintained at 21%-21.5%, which is much higher than that of ordinary industrial-grade ammonium sulfate (usually 20%-20.5%). Additionally, the sulfate ion (SO₄²⁻) content reaches 54%-55%, with a balanced nutrient ratio. It can meet the requirements of high-precision fertilization without additional purification.
The purity of ammonium sulfate is ≥99.5%, and the content of impurities (such as heavy metals lead, cadmium, mercury, as well as chloride ions, iron ions, etc.) is extremely low. Among them, the content of each heavy metal is ≤0.0005%, and the chloride ion content is ≤0.01%—far below the limits specified in the National Standard for Agricultural Ammonium Sulfate (GB/T 535-2020), which requires "heavy metals ≤0.002% and chloride ions ≤0.2%". This makes it safer for crops and soil.
The crystals have a regular orthorhombic crystal system structure, with uniform particles (particle size usually ranging from 0.2mm to 0.5mm) and good fluidity. They are not easy to absorb moisture and agglomerate (the critical relative humidity is about 81%, higher than the 75% of ordinary ammonium sulfate), which facilitates storage, transportation, and subsequent processing.
