Bottom spraying type limestone smelting method of combined top-bottom combined blowing converter

Abstract

The invention provides a bottom spraying type limestone smelting method of a combined top-bottom combined blowing converter. According to the technical scheme, the method is characterized in that limestone is crushed into powder with certain particle size; the limestone powder is directly sprayed into molten steel in a smelting pool of the converter through a bottom blowing pipeline and a ventilating spraying arranged at the bottom of the combined blowing converter and blowing element under the effect of high-pressure carrier gas; the limestone powder is directly sprayed into the bottom of theconverter through the high-pressure carrier gas on the basis of continuing to blow oxygen from the top, so that the specific surface of the limestone and inner elements of the molten steel in reaction can be expanded without limitation; CO2 and CaO are generated by heating and decomposing the limestone and are used for supplying an oxidizing atmosphere and an alkaline environment for inner smelting of the converter; the limestone is decomposed through surplus energy in smelting of the converter; the limestone is sprayed and blown through the high-temperature carrier gas, and materials in thesmelting pool can be fully stirred, so that the steel slag reaction is further promoted. With the adoption of the method, the energy is effectively saved; the smelting cost is decreased; the smeltingprogress is improved; and the quality of the smelting molten steel of the converter is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a compound type top-bottom combined blowing converter bottom-spraying limestone smelting method. Background technique [0002] At present, converter steelmaking is mostly carried out by top-bottom double-blowing converter. The common method of top-bottom double-blowing converter steelmaking is to use the top-blowing oxygen lance on the upper part of the converter to blow oxygen into the molten pool, and blow nitrogen or argon to the molten pool from the bottom of the converter. , realize the effective emulsification of slag, fully release the steel slag reaction interface, improve the smelting efficiency, and add the slag-making material from the furnace mouth through the silo; The efficiency is not high, and the consumed lime needs secondary sintering processing, which is neither energy-saving nor environmentally friendly, and increases the cost at the same time. ...

AI Technical Summary

Problems solved by technology

[0002] At present, converter steelmaking is mostly carried out by top-bottom double-blowing converter. The common method of top-bottom double-blowing converter steelmaking is to use the top-blowing oxygen lance on the upper part of the converter to blow oxygen into the molten pool, and blow nitrogen or argon to the molten pool from the bottom of the converter. , realize the effective emulsification of slag, fully release the steel slag reaction interface, improve the smelting efficiency, and add the slag-making material from the furnace mouth through the silo; The efficiency is not high, and the consumed lime needs to be sintered twice, which is neither energy-saving nor environmentally friendly, but also increases the cost

[0003] Chinese invention patent [CN 102796841A] injecting limestone powder to the converter molten pool at the side of the converter trunnion, to a certain extent, promotes the stirring effect of the molten pool and the utilization efficiency of limestone, and injects lime powder from the side, and the carrier gas and lime powder are The residence depth and time in the molten pool are limited, and the injection range is limited to a local area, which cannot make full use of the rich heat of converter smelting and fully stir the molten pool

[0004] Chinese invention patent [201210240821.3] discloses a steelmaking method of slagging powdered limestone with oxygen lance injection in a re-blown converter. The inventor has modified the structure of the oxygen lance and used the oxygen lance to simultaneously inject limestone powder and oxygen But the problem with this is that limestone is easily taken away by the airflow, resulting in low utilization rate of limestone and dust pollution. At the same time, it takes time and energy to modify the structure of the oxygen lance, and the maintenance requirements of the oxygen lance are greatly increased.

This method is limited to strengthening the agitation of the molten pool for dephosphorization, but there is no specific plan for how to realize the injection of lime powder into the molten pool.

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