Molten iron full-domain stirring and desulfurization stirrer and using method thereof

Abstract

The invention discloses a molten iron full-domain stirring and desulfurization stirrer. The stirrer comprises a stirring shaft, a stirrer connecting flange, upper-layer stirring blades and lower-layerstirring blades, each upper-layer stirring blade and each lower-layer stirring blade each comprises a stirring blade core and a stirring blade core fire-resistant pouring material lining, each upper-layer stirring blade is a left-rotated spiral blade rotating in the same direction as the stirring direction, each lower-layer stirring blade is a right-rotated spiral blade rotating in the directionopposite to the stirring direction, and the lower-layer stirring blades and the upper-layer stirring blades are arranged at the same circumferential angle in the circumferential direction of the stirring shaft or are arranged in a front-back equal-angle staggered angle mode. Through the double-layer stirring blade structure arranged up and down, the arrangement distance of the stirring blades in the length direction of the stirring shaft is greatly increased, the stirring depth and the effective stirring area of the stirrer on the molten iron in a molten iron ladle are expanded, stirring of the molten iron at the bottom of the molten iron ladle and stirring, mixing and mass transfer of the full-domain molten iron are remarkably enhanced, and the dynamic conditions of the full-domain molteniron stirring and desulfurization reaction are greatly improved.

Description

technical field [0001] The invention relates to the field of molten iron pretreatment, in particular to an agitator for global stirring and desulfurization of molten iron and a method for using the same. Background technique [0002] According to relevant reports, hot metal desulfurization pretreatment is the most economical process for reducing the mass fraction of sulfur in steel in the blast furnace converter-continuous casting process, and is also one of the important means to improve the operation of blast furnaces and converters. For this reason, since the 1970s, the A series of molten iron desulfurization pretreatment processes represented by injection desulfurization and KR stirring desulfurization have been popularized and applied successively. Among them, the KR mechanical stirring desulfurization process of molten iron has become the preferred process for efficient, stable and deep desulfurization of molten iron due to its excellent stirring and mixing kinetic char...

AI Technical Summary

Problems solved by technology

(3) Tangential flow, in a container without baffles, the fluid rotates around the stirring shaft. When the flow velocity is high, the fluid will form a vortex. At this time, the flow of the fluid from the circumference of the paddle to the paddle area is very small. poor mixing

Although this method has achieved good industrial test results in actual production, due to the large eccentric thrust of eccentric stirring, the wear of the brake system of the molten iron tanker has been promoted, and the maintenance workload of the molten iron tanker has been increased, which has brought great harm to the actual application. come difficult

The Chinese patent "Mechanical Stirring Desulfurization Method for Desulfurization Pretreatment of Hot Metal, Application Publication No.: CN106244759.A" discloses a stirring desulfurization method that uses a wall baffle to suppress the stirring tangential flow. The blocking effect of the baffle prevents the tangential flow of the agitation, strengthens the axial flow and radial flow of the agitation, and achieves the purpose of improving the mixing characteristics of the agitation. However, due to the difficulty in the installation and use of the baffle from the wall, there are no reports of practical application.

The Chinese patent "jet agitator for mechanical stirring and desulfurization of molten iron, authorized announcement number: CN102154533.B" discloses a new type of agitator that improves the dynamic conditions of agitation by blowing between blades, using the cooling of the air-cooled tube in the metal core of the agitator shaft Nitrogen, through the diffuse nozzles set between the blades of the agitator, injects nitrogen into the forced vortex area of ​​the agitation, improves the turbulent flow in the forced vortex area, suppresses tangential flow, strengthens axial flow and radial flow, promotes agitation and mixing, and improves agitation desulfurization Kinetic conditions, due to the difficulty of achieving a stable injection of nitrogen on a rotating body agitator, have not been applied in actual production at present

Through the staggered arrangement of the two-layer blades, the invention realizes the superposition effect of the axial flow of the two-layer blades, improves the stirring and pulling-down depth of the desulfurizing agent, expands the stirring and mixing area of ​​the desulfurizing agent, and prolongs the entrainment and floating cycle stroke of the desulfurizing agent in molten iron. As well as the purpose of improving the degree of mixing and dispersion of desulfurizer particles and the desulfurization efficiency of molten iron; although the invention effectively expands the stirring and mixing area, which is beneficial to the improvement of the mass transfer process of molten iron in the molten iron tank, the effective height of the stirring blade restricts the self-floating particles The depth of the pull-down still cannot achieve effective stirring of the molten iron in the lower part of the molten iron tank and its mixing with the desulfurizer, and the full stirring effect of the molten iron in the entire area of ​​the molten iron tank has not yet been achieved.

[0006] Based on the above, it can be seen that strengthening the axial flow and radial flow and suppressing the tangential flow is the key to improving the kinetics of the mechanical stirring desulfurization reaction of molten iron. Although domestic and foreign scholars have made a lot of efforts to this end, a series of improvement technical solutions have been formed. Some improved technologies have achieved the purpose of significantly expanding the stirring and mixing area and the mixing and dispersing effect in the water model test, but due to the limitations of high temperature, high-power stirring, intermittent production and other harsh working conditions of mechanical stirring and desulfurization of molten iron, the improvement measures are difficult. It is stably implemented in actual production, such as: positive and negative rotation pulse stirring, wall-attached and off-wall baffles, eccentric stirring, etc.; in addition, some blade structure improvement technologies have been applied in actual production and achieved good improvement effects, but Due to the local stirring and mixing characteristics of the single-layer blade structure, it still cannot meet the improvement goal of global molten iron stirring in the molten iron tank

Although the agitator with multi-layer blade structure can theoretically realize the agitation of the molten iron in the upper, middle and lower areas of the molten iron tank and achieve the purpose of strengthening the mass transfer process of molten iron, there is no systematic research on the expansion of the self-floating particle agitation, dispersion and mixing area of ​​the molten iron desulfurization by stirring and desulfurization. How to realize the mixed reaction of molten iron and desulfurizer in the whole region needs further research

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