The mixing device for producing the compound coloring agent comprises a tank body and a tank cover which are connected into a whole through a
flange, the tank cover is provided with a feeding port, and the bottom of the tank body is provided with a discharging port; a mounting frame, a rotary power mechanism, a stirring shaft and a stirring unit are arranged on the tank cover; the tank cover is provided with an upper bracket, a
nitrogen supply ring
pipe, a
nitrogen outlet hole and a tank body air emptying port; a lower bracket, an
argon supply ring
pipe and an
argon outlet hole are arranged on the tank body; a
heat exchanger is also sleeved on the outer wall of the middle part of the tank body; the mixing device is provided with a
nitrogen and
argon dual
inert gas protection system, nitrogen can be uniformly introduced into the upper part of the tank body through the annular
pipe and the
gas supply hole of the nitrogen supply
assembly on the tank cover, and air in the tank body is naturally discharged from the air
discharge port of the tank body, so that the contact between
oxygen and materials is reduced, the
oxygen is effectively isolated, and the
material quality is improved. Oxidative deterioration of the coloring agent is prevented, and color stability and
quality safety of the product are guaranteed to the maximum extent.