Preparation Method 4 for Polymerized Ferric Sulfate

Preparation Method 4 for Polymerized Ferric Sulfate:
Nitric Oxidation:
Nitric acid, a moderate oxidant, reacts with ferrous ions as follows:
FeSO4 + HNO3 → Fe(OH)SO4 + NO2
The resultant NO2 performs oxidation, enhancing the efficiency of HNO3.
This method employs industrial FeSO4 as the feedstock. After oxidative treatment with industrial sulfuric acid, it undergoes nitric acid oxidation. The ratio of FeSO4:HNO3 is 1:(0.20~0.30):(0.10~0.32). Less than 20% of the total volume is water added under 0.1~0.2MPa, sufficient air or oxygen is introduced during stirring at 50~70°C, and the reaction is completed at 102~103°C through hydrolysis and polymerization. The reaction cycle should be within 30~60 minutes.
Nitric acid oxidation is cost-effective and shortens the reaction cycle. The product has high concentration and can be easily converted into solid state. When employing industrial-grade raw materials, the resultant product can be used in potable water treatment. However, the generated NO2 causes environmental pollution and requires specialized absorption equipment for disposal.