Ammonium sulfite is recommended for use as an agricultural fertilizer

As shown in Tables 5 to 8, the ammonia-ammonium sulfite method is relatively simple and involves lower equipment construction costs. This is because the method directly produces ammonium sulfite as the final product, eliminating the need for further processing such as sulfuric acid decomposition or air oxidation, thereby simplifying the process. Additionally, since the solubility of (NH₄)₂SO₃·H₂O at room temperature is significantly lower than that of (NH₄)₂SO₄, the (NH₄)₂SO₄ solution must be evaporated and crystallized by steam heating to obtain the solid (NH₄)₂SO₄ product.