Abstract: Aiming at the carbonization process of the calcification-carbonization method for low-graded bauxite and red mud， a “three-stage cross-flow Venturi jet reactor” was proposed to make bubble disintegrate and disperse uniformly and to improve carbonization rate. Physical simulation in carbonization reactor was also carried out. Local gas holdup and bubble rising velocity under different operating conditions were investigated. The results showed that the gas holdup increases with increase of the superficial gas velocity and decreased with increase of the superficial liquid velocity， while it also decreased along the axial direction of the reactor. The gas holdup in the latter stage of the reactor was higher than that in the former one. The bubble rising velocity increased with increase of the superficial gas velocity and superficial liquid velocity， and it decreased along the axial direction of the reactor. The bubble rising velocity in the latter stage of the reactor was higher than that in the former one. The results provide a theoretical and experimental basis to design the carbonization reactor and to guide its applications in industry.

Key words: carbonization, jet, gas holdup, bubble rising velocity, physical simulation