Mechanical stirring desulfurization method for desulfurization pretreatment of molten iron

Abstract

The invention discloses a mechanical agitation desulphurization method for molten iron desulphurization pretreatment. The desulphurization method includes five steps including prior sample taking for temperature measurement, prior slag scrabbling, desulfurizing agent adding and agitation, later slag scrabbling and later sample taking for temperature measurement. In the steps of desulfurizing agent adding and agitation, an agitation device is inserted into a molten iron tank containing molten iron, and is composed of an agitator and a guide plate, and the guide plate and the agitator are both vertically instead into the molten iron; and the vertical distance between the bottom of the guide plate and the top of a blade of the agitator is H. Compared with the rotating speed of a conversional KR method, the rotating speed of the agitator is decreased by 10% to 20%; and the insertion depth of the agitator is increased by 10% to 30% compared with the insertion depth of the conversional KR method.

Description

technical field [0001] The invention relates to an out-of-furnace desulfurization method of molten iron before converter steelmaking, in particular to a mechanical stirring desulfurization method used for desulfurization pretreatment of molten iron. Background technique [0002] Mechanical agitation desulfurization of molten iron is through the rotation and agitation of the agitator inserted into the molten iron in the molten iron tank, so that the molten iron and desulfurizer are mixed and contacted for desulfurization. There are mainly Rhine method and KR (Kambara Reactor) method. The agitators used in these two methods of mechanical stirring desulfurization of molten iron are composed of a rotating shaft and stirring blades. The four stirring blades are evenly arranged in a cross shape along the circumference of the rotating shaft, and the agitator is inserted into the molten iron along the center line of the molten iron tank; the difference is only in the agitator The de...

AI Technical Summary

Problems solved by technology

The Chinese patent "KR method desulfurization tank bottom blowing method" (patent application number: 200610124845.7) provides a KR method desulfurization tank bottom blowing method, which is based on the KR method and blows into the tank through the breathable bricks arranged at the bottom of the tank. Inject high-pressure nitrogen to promote the floating of desulfurization slag in molten iron, so as to increase the desulfurization speed and the purity of molten iron, but shorten the residence time of desulfurizer in molten iron. cost

Although the combined desulfurization method of injection and stirring improves the dynamic conditions of desulfurization, the high-pressure rotary sealing of the injection system is difficult, the reliability is poor, and the equipment investment is large, which is difficult to meet the needs of safe and stable production, and has not been popularized and applied.

The Chinese patent "Molten Iron Mechanical Stirring Desulfurization Method" (publication number CN101492753A) discloses an eccentric stirring desulfurization method for molten iron tanks. The stirring of the stirrer away from the center of the molten iron tank causes the center of the stirring vortex to deviate from the stirring axis, which prevents the conventional KR stirring desulfurization The formation of the forced vortex zone in the stirring center makes the desulfurization agent inhaled by the vortex deviate from the stirring axis asymmetrically and be involved in the circulation, and realize the mixing and dispersion of the desulfurizing agent involved in the molten iron through the impact of the agitator blades, thereby effectively improving The dynamic conditions of hot metal mechanical stirring desulfurization have been studied. Although good industrial test results have been obtained in actual production, the large eccentric thrust of eccentric stirring has promoted the wear of the brake system of the hot metal tank car and increased the maintenance work of the hot metal tank car. quality, which brings difficulties to the actual promotion and application

It can be seen that the improvement of the structure of the agitator mentioned above mainly achieves the effect of improving the kinetic conditions of the mechanical agitation desulfurization of molten iron by strengthening the mixing and dispersion in the free vortex zone of the agitation. The volume of the forced vortex zone cannot be reduced, which restricts the significant improvement of the kinetic conditions of the mechanically stirred desulfurization of molten iron

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