Converter smelting process with low lime consumption

Abstract

The invention discloses a converter smelting process with low lime consumption. The process comprises the steps that part of final slag is reserved according to the content of P2O5 in converter slag before converter tapping; after tapping, a deoxidizer is added according to the FeO content in the slag to reduce the oxidizability of the slag; all light-burned dolomite required in the dephosphorization period is added, slag splashing furnace protection operation is carried out, scrap steel is added firstly, and all lime required in the dephosphorization period is added; molten iron is added after the lime is added, a deoxidizing gun is ignited, and return ore or ore is added to adjust slag components after ignition; after the dephosphorization time, the carbon content and the temperature reach the requirements, inverse dephosphorization slag operation is carried out; after slag pouring is finished, the deoxidizing gun is ignited for the second time, and the feeding amount is controlled according to the alkalinity requirement; and oxygen supply is stopped when the carbon and the temperature meet the requirements, and part of the final slag is reserved according to the mass percentagecontent of P2O5 in the final slag for next smelting in the furnace. Lime consumption is reduced, the converter slag amount and the steel material consumption are reduced, and the problems of phosphorus enrichment, phosphorus return and dry dedusting explosion release in the slag are avoided.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy converter steelmaking, and in particular relates to a converter smelting process with low lime consumption. [0002] technical background [0003] The main component of lime is CaO, which is the main slagging material for steelmaking. It has the ability of dephosphorization and desulfurization, and it is also the most used slagging material for steelmaking. In converter steelmaking, the increase in lime consumption will lead to an increase in the amount of slag in converter smelting, which in turn will cause iron loss, increased consumption of steel materials, and increased production costs of converters. Therefore, smelting with low lime consumption has always been the focus of attention of various iron and steel enterprises; Especially in recent years, with the increasing pressure of environmental protection, reducing lime consumption, reducing environmental pollution and enterp...

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Problems solved by technology

For example, the patent "A Method for Converter Operation of Limestone Smelting Low Phosphorus Steel" (201410320701.3) discloses a method of using limestone instead of lime in converter smelting. This method avoids environmental pollution caused by lime calcination and improves the utilization rate of lime , but this method will lead to an increase in the amount of converter slag and an increase in the consumption of steel materials, and this method requires a high degree of heat abundance of the converter, which is not conducive to the improvement of the scrap ratio of the converter; the patent "Method for double-slag smelting of converter using corundum slag" (201611044136.8) disclosed a method of using corundum slag to replace part of lime to reduce lime consumption. Although this method can reduce part of lime consumption, the Al contained in this method 2 o 3 It will lead to faster erosion of the converter lining and an increase in the number of furnace repairs, which will affect the production of the converter. In this method, slagging is performed when the carbon content is between 0.8% and 1.2%, and then slagging is carried out. However, due to the low content in the second slagging process, it will be difficult to raise the temperature in the later stage of the converter, and the secondary leakage If the explosion problem is not controlled, it will lead to an increase in the frequency of converter explosion venting and affect the smooth production; the patent "a steelmaking method for semi-steelmaking with double slag and slag retention" (201210544071.9) considers the reuse of the final slag of the converter and the slag retention However, there are misunderstandings about the enrichment of phosphorus in the converter slag and the control of the detailed process parameters in the early stage of the converter, which leads to poor dephosphorization efficiency of the converter, little savings in lime consumption, and does not consider the problem of converter explosion venting; the patent "a high-efficiency Low-cost converter to produce ultra-low phosphorous molten steel technology" (201210020934.2) Although the double-slag smelting process was proposed, the control system for the specific early-stage smelting process was not refined, which was not conducive to guiding the operation; the patent "Converter smelting with low lime consumption "Steel Method" (201410026518.2) also proposed the operation method of converter slag, but did not give specific instructions on the enrichment of phosphorus in the slag and the detailed process operation, making it difficult to implement the process

[0005] In the prior art, a converter smelting process with low lime consumption that can be comprehensively considered from the aspects of slag remaining, blowing operation process, dephosphorization efficiency and production continuity has not been found. Therefore, it is necessary to combine the entire converter production process to develop A converter smelting process capable of reducing lime consumption

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