Multi-section multi-speed molten iron rotary blowing desulfurization method

The invention provides a multi-section multi-speed molten iron rotary desulfurization method. The method comprises the step that a molten iron desulfurization process comprises a plurality of stages with different molten iron rotation speeds. Only one constant rotating speed can be set in the existing common rotary injection molten iron desulfurization control technology, and optimal control cannot be performed aiming at different stages of the molten iron desulfurization injection process. When the rotating speed of molten iron rotary desulfurization blowing is high, the radial diffusion of a desulfurizing agent in the molten iron is weak, but the uniformity in the circumferential direction is better, the splashing of the molten iron is relatively weak, the scouring of the molten iron to a gun body is relatively strong, and the service life of the gun body is relatively short; and when the rotating speed is low, the desulfurizing agent is strongly diffused in the radial direction of molten iron but poor in u