Efficient mixing stirrer for molten iron desulphurization

Abstract

The invention discloses an efficient mixing stirrer for molten iron desulphurization. The efficient mixing stirrer comprises a stirrer connecting flange, a stirring shaft and a plurality of stirring blades fixed to the peripheral edge of the stirring shaft and circumferentially and uniformly distributed around the stirring shaft, and the stirring shaft comprises a stirring shaft core and a stirring shaft core fire-resistant casting material liner. The upper end faces and the lower end faces of the stirring blades are both horizontal planes, the iron facing faces and the back iron faces are all spiral faces, and the outer side faces of the stirring blades are spiral faces of circular table outer edge arc faces. The radius of the upper end face of a circular table is larger than that of the lower end face of the circular table. According to the efficient mixing stirrer for molten iron desulphurization, the axial and radial stirring mixing areas of a desulfurizer in the molten iron mechanical stirring desulphurization process can be enlarged in actual production, the entrainment circulating flow is increased, shearing power consumption is reduced, and finally, the expected purposes that the molten iron KR stirring desulphurization dynamic condition is improved, the desulfurizer mixing and dispersing depth is increased, the stirring imbalance harm is avoided, and the KR mechanical stirring desulphurization transformation requirement of a thin-long blowing desulfurization molten iron tank is met are achieved.

Description

technical field [0001] The invention relates to the field of molten iron pretreatment, in particular to a high-efficiency mixing agitator for molten iron desulfurization. Background technique [0002] The literature "External desulfurization of molten iron, Shanxi Metallurgy, 2007, No1" reported that molten iron is the basic raw material for molten steel smelting, and its chemical composition and physical properties determine the quality of steel products and the benefits of enterprises to some extent. Among them, Sulfur is one of the main harmful elements in iron and steel products (except for sulfur-containing steels), so it must be removed; if it can be removed in the blast furnace ironmaking process, the slag alkalinity and furnace temperature must be increased, leading to blast furnace technology The economic indicators have dropped sharply. If it is removed during the converter smelting process, due to the thermodynamic conditions of the converter smelting process, the...

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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

The Chinese patent "A Stirrer for Desulfurization of Hot Metal" Patent No. ZL200910060770.4 discloses a three-blade agitator whose stirring blades face the iron surface and the back iron surface are both front inclined surfaces. The suction space and the entrainment circulation flow can improve the dynamic conditions of desulfurization, and increase the angle between the leaves to 120°, reduce the speed of sticky slag between the leaves, facilitate the cleaning of sticky slag, and increase the agitation intensity. Stability, but the inclined plane structure of the stirring blade facing the iron surface and the back iron surface leads to a limited inclination angle, otherwise the stirring blade will deviate from the stirring shaft core by a large distance, and the deviation distance is different, causing the agitator to rotate and stir unbalanced, especially After the uneven wear and crack peeling of the mixing blade, the imbalance problem is extremely serious, and even endangers the safety of the mixing system, so the improvement effect is not outstanding

The Chinese patent "Turbine Agitator for Mechanical Stirring and Desulfurization of Hot Metal" Patent No. ZL201010196917.5 discloses a three-blade agitator composed of a rotating shaft, a hub and stirring blades, which increases the circumference of the uniformly arranged circumferential direction of the stirring blades , which facilitates the arrangement of the leaves and the preparation of the agitator, so that the angle ф between the tangent line between the end line of the agitation blade and the intersection point of the iron water surface and the hub can reach the range of 132-180°, which reduces the stagnation of the agitation fluid caused by the knuckle angle of the agitation shaft. It slows down the speed of sticky slag at the knuckles and the mechanical damage caused by the cleaning of sticky slag, increases the surface area of ​​the stirring blade against the iron and the stirring radial thrust, and improves the mechanical efficiency of stirring and the degree of mixing and dispersion. The forward-inclination planar structure of the iron surface and the back-iron surface still cannot solve the problem of limited forward inclination angle

For the injection desulfurization process, in order to effectively prolong the residence time of the desulfurizer in the molten iron, the molten iron tanks are all designed as "slender" structures whose ratio of the depth of the molten iron level to the average diameter of the molten iron tank is greater than 1. Based on the KR stirring desulfurization reaction kinetics The conditions are far superior to the technology of injection desulfurization, and domestic and foreign iron and steel enterprises retain the "slender" shaped injection desulfurization hot metal tanks to carry out KR agitation desulfurization transformation work is rapidly advancing, and the lack of local mixing characteristics of KR agitation desulfurization is more prominent, resulting in desulfurization Technical and economic indicators have seriously deteriorated

Regarding the adaptability of the existing KR desulfurization technology to the "slender" shaped molten iron tank and how to change the local mixing characteristics of KR stirring desulfurization, there are no relevant reports. It is urgent to develop a new type of blade structure agitator with excellent performance. To strengthen the stirring axial flow and radial flow, further improve the mechanical stirring desulfurization reaction kinetics of molten iron, improve the desulfurization efficiency and desulfurization agent effective utilization rate, shorten the stirring time, etc.

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