The invention relates to a method for purifying
liquid steel in
tundish by the composition of a rotary
electromagnetic field and a tangential diversion and a device. The method is that the generating device of the rotary
magnetic field generates the rotary electromagnetic force to drive steel water in a
tundish rotary chamber to generate the rotary flow, which is characterized in that the vertical
impact flow of a
ladle nozzle is guided to horizontal tangential to flow into the rotary chamber to form the power of the rotary flow, then the power of the rotary flow is composed with the rotary electromagnetic force to allow the steel water in the rotary chamber to generate the symmetric rotary flow, and the
centrifugal force is utilized to separate the non-
metallic impurities from the steel water. The device is the
tundish which contains the rotary chamber, which is characterized in that the rotary chamber is connected with a guide slot along the tangent, the
ladle nozzle is arranged in the guide slot, and the outside of the rotary chamber is provided with a generating device of the fan-shaped rotary
magnetic field. The invention adopts the composition of the rotary
electromagnetic field and the tangential guide flow, thus enhancing the rotation intensity of the steel water, reducing the input power and the
energy consumption of the generating device of the rotary
magnetic field, eliminating the damage function of the
ladle injection flow on the
centrifugal separation of inclusions and improving the purification effect.