This device is applied to fume dry deacidification. Set the baking soda raw material warehouse of about 60 mesh on the ground. After weight loss or spiral measurement, put it into the grinder and grind to about 500-600 mesh powder. Then it is conveyed to the entrance of the reaction tower or bag filter by a tan, and is fully mixed to with the fume to remove the acid gas (SOx, HCI, HF) in the fume. Under the condition of ensuring better fume emission indicators, the consumption is about 1/3 of the amount of slaked lime.