The acid mist exhaust gas is introduced into the purification tower through the air duct, passes through the packing layer, and undergoes gas-liquid two-phase contact absorption and neutralization reaction with the sodium hydroxide absorption solution. After purification, the acid mist exhaust gas is dehydrated and defogged by the defogging plate before being discharged into the atmosphere by the fan. The absorption liquid is pressurized by a water pump at the bottom of the tower, sprayed down from the top of the tower, and finally refluxed to the bottom for recycling. The purified acid mist exhaust gas meets the emission requirements of the local emission standards in Guangdong Province and is lower than the national emission standards.