The treatment principle of the spray tower: Acid mist waste gas is introduced into the purification tower through a duct, and after passing through the packing layer, the waste gas and sodium hydride absorbent are fully contacted with the gas and liquid to absorb and neutralize the gas. After purification, the acid mist waste gas is dehydrated by the dust board and then discharged into the atmosphere by a fan. The absorbent is sprayed from the top of the tower after being pressurized by a pump at the bottom, and then it recirculates back to the bottom. The purified acid mist waste gas meets the emission standards.