Desulfurization method for hot metal pretreatment

Abstract

The invention discloses a desulphurization method used for pretreatment of molten iron. The desulphurization method used for pretreatment of the molten iron comprises the steps that firstly, after continuous casting or mold casting is completed, hot slag in a steel ladle and surplus casting molten iron are poured into an iron ladle; next, the iron ladle is conveyed to an iron outlet station, and apreset amount of molten iron with a preset temperature is added; then, through a KR stirring desulphurization process, stirring desulphurization is carried out, and in the desulphurization process, no desulphurization agent is added; and lastly, after the desulphurization step is completed, the desulphurized molten iron is fed into a converter to be smelted. According to the desulphurization method used for pretreatment of the molten iron, hot refining slag in the steel ladle and the surplus casting molten iron are circularly returned into the iron ladle, the lime and fluorite mixture desulphurization agent is not added any more in the KR stirring desulphurization process, the desulphurization efficiency is high, the molten iron temperature reduction is small, and the desulphurization speed is high; and tests prove that after pretreatment of the molten iron is completed, the sulphur content can reach 0.0015%, 4.0kg / t-8.0kg / t of desulphurization agents are saved, the cost is reduced by2.4 Yuan / t-4.8Yuan / t, meanwhile, hot state utilization of the slag is achieved, and the slag treatment cost of following processes and the environment pollution are reduced.

Description

technical field [0001] The invention relates to the technical field of molten iron pretreatment and solid waste recycling in the iron and steel smelting industry, in particular to a desulfurization method for molten iron pretreatment. Background technique [0002] Currently, hot metal pretreatment desulfurization mainly includes KR (Kambara Reactor, Kambara Reactor) stirring desulfurization method and molten iron injection method. As a mechanical stirring desulfurization method, the KR stirring desulfurization method is widely used because of its excellent desulfurization kinetic conditions, high desulfurization rate (desulfurization rate is greater than 90%) and good desulfurization stability. [0003] However, the KR stirring desulfurization method has the following problems: first, the temperature drop is relatively large during the molten iron desulfurization process; second, the KR stirring desulfurization method needs to use a desulfurizing agent, which is a mixture of...

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Problems solved by technology

[0003] However, the KR stirring desulfurization method has the following problems: first, the temperature drop is relatively large during the molten iron desulfurization process; second, the KR stirring desulfurization method needs to use a desulfurizing agent, which is a mixture of CaO and fluorite. Therefore, The above desulfurizers need lime with high activity and CaF-containing 2 Higher raw materials, and need to use a special production process to produce, the cost is higher; third, because the desulfurizer contains about 10% CaF 2 , in the process of desulfurization, it will cause intensified erosion of the ladle, resulting in environmental pollution

The first is to pour the ladle refining slag into the slag tray and transport it to the slag yard for treatment. The treated steel slag is used as the roadbed for paving roads or as cement raw materials. However, the disadvantage of this treatment is that it requires a large amount of storage space and is easy to cause environmental pollution

The second is to mix the ladle refining slag with certain binder to make pellets after cooling treatment, and add it to the converter as a slagging agent after drying. However, this method requires special equipment for processing, and the cost is relatively high.

The third is to return the ladle refining slag to the ladle refining furnace for use. However, this method is likely to cause sulfur enrichment during the ladle refining process, which affects the molten steel refining effect, reduces the desulfurization rate of the refining furnace, and needs to be discarded after 2 to 3 furnaces. One-time slag cannot realize continuous return and utilization

[0005] Therefore, there is a need in this field for a new desulfurization method for molten iron pretreatment, which can solve the problems of high desulfurization agent consumption, ladle slag cannot be used in hot state, and high slag treatment cost in the molten iron pretreatment process.

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