1. Wastewater: The process wastewater from the production of Sodium Metabisulfite comes from the washing process, and the main pollution factors are impurities such as sodium sulfite, sulfuric acid, and sulfur. This dilute acid water is a common problem in the Sodium Metabisulfite industry. The amount of wastewater generated is approximately 50-80kg per ton of Sodium Metabisulfite product. The current treatment processes mainly include lime neutralization, soda ash neutralization, and the production of magnesium sulfate. The neutralization cost of lime is low, with the generation of solid waste such as calcium sulfate. The neutralization cost of soda ash is high, and there is no solid waste generated. The production of magnesium sulfate is a good direction, but it requires convenient magnesium resources and relatively more investment.

2. Waste gas: Sodium Metabisulfite waste gas comes from synthetic exhaust gas and drying exhaust gas. Washing with soda ash is the most effective and reasonable treatment method, and the absorption liquid can be reused in the alkali preparation process. This not only achieves the standard emission of exhaust gas, but also improves the sulfur recovery rate. The treatment equipment generally uses a packed absorption tower, which removes SO2 from the tail gas through countercurrent absorption.

Environmental Protection Issues in the Production Process of Sodium Metabisulfite