The invention relates to a double-cone mixer which comprises a mixing cylinder, a machine frame for supporting the mixing cylinder and a mixing cylinder driving mechanism, wherein the mixing cylinder driving mechanism comprises a motor, a worm gear reducer, a rotating shaft and a bearing carrier; the motor drives the worm gear reducer to operate, the worm gear reducer is connected with the rotating shaft in a transmission mode, and the rotating shaft penetrates through the bearing carrier and drives the mixing cylinder to rotate; the double-cone mixer is also provided with a cut-off valve, an air bag, an explosion-proof electromagnetic pulse valve, an injection pipe and an air cannon stirring bracket which are contained in an air cannon unblocking device; the inside of the air cannon stirring bracket is hollow; an air outlet of the cut-off valve is connected with an air inlet of the air bag; an air outlet of the air bag is connected with an air inlet of the explosion-proof electromagnetic pulse valve; one end of the injection pipe is connected with an air outlet of the explosion-proof electromagnetic pulse valve; the other end of the injection pipe communicates with the air cannon stirring bracket; and a plurality of air holes are arranged outside the air cannon stirring bracket. The double-cone mixer implements automatic control, is convenient to operate, enhances the production efficiency, lowers the noise, prolongs the service life of the mixing cylinder and ensures the safety of operators.