Combined rotary kiln incineration system capable of fully burning slag

The invention discloses a combined rotary kiln incineration system capable of fully burning slag. The combined rotary kiln incineration system comprises a rotary kiln, a vertical slag burning chamber,a rotary grate, a slag discharging device and a secondary combustion chamber; the front end of the rotary kiln is provided with a feeding port, and the kiln tail of the rotary kiln is connected withthe upper end of the vertical slag burning chamber; the rotary grate is arranged at the bottom of the vertical slag burning chamber, a slag discharging opening is formed below the rotary grate, and aslag discharging device is arranged below the slag discharging opening; a flue gas outlet is formed in the side wall of the upper portion of the vertical slag burning chamber, the flue gas outlet is connected with the secondary combustion chamber, and a high-temperature flue gas outlet is formed in the top of the secondary combustion chamber; and a combustion-supporting air inlet is formed below the side face of the rotary