Converter less-slag smelting method

Abstract

The invention relates to a converter less-slag smelting method. The converter less-slag smelting method uniformly adopts a less-slag single-slag mode under the conditions of high iron consumption or low iron consumption and complex molten iron silicon change. The converter less-slag smelting method comprises the following process flows of: finishing tapping, remaining slags, adjusting the slags, splashing the slags, adding scrap steel, mixing molten iron, conducting calculation, conducting blowing, controlling an end point and tapping. In the smelting process, the lance position and the oxygen supply intensity are controlled by referring to the CO value; the end oxidizability is effectively controlled through heat balance accurate calculation; the molten steel oxidizability is reduced through process low lance position control; the alloying cost is effectively reduced; and meanwhile, the final slag oxidizability is reduced; the slag splashing furnace protection effect is promoted; and the furnace condition maintenance cost is effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to a converter slag-less smelting method. Background technique [0002] In recent years, with the promotion of the elimination of backward production capacity such as "floor steel" produced by intermediate frequency furnaces, the scrap steel resources that originally flowed to intermediate frequency furnace enterprises have gradually been digested by electric arc furnaces and converters. It is not high, and there is no cost advantage compared with the converter. Therefore, the converter eats more scrap steel and becomes one of the most important technical measures for iron and steel enterprises to increase production, reduce costs and increase efficiency. [0003] With the continuous increase of the proportion of scrap steel and the decrease of the proportion of molten iron, the physical and chemical heat brought by the molten iron into the converter is reduced, whic...

AI Technical Summary

Problems solved by technology

[0002] In recent years, with the promotion of the elimination of backward production capacity such as "floor steel" produced by intermediate frequency furnaces, the scrap steel resources that originally flowed to intermediate frequency furnace enterprises have gradually been digested by electric arc furnaces and converters. It is not high, and there is no cost advantage compared with the converter. Therefore, the converter eats more scrap steel and becomes one of the most important technical measures for iron and steel enterprises to increase production, reduce costs and increase efficiency.

[0003] With the continuous increase of the proportion of scrap steel and the decrease of the proportion of molten iron, the physical and chemical heat brought by the molten iron into the converter is reduced, which breaks the original heat balance and brings a series of problems to production, quality and safety. In order to solve these problems, people Developed technologies such as scrap steel preheating, secondary combustion oxygen lance, converter temperature raising agent, and even blowing iron oxide materials after converter drawing to raise the temperature, but these technologies have great disadvantages

[0004] In order to make up for the lack of heat caused by the increase of steel scrap, some enterprises now use equipment for preheating steel scrap outside or inside the converter, because the baking temperature is relatively low, or it is in the low temperature section for a long time, and cannot reach 850°C The above dioxin decomposition temperature produces a large amount of carcinogens, which is incompatible with the new development concept of the new era

[0005] The secondary combustion oxygen lance can increase the secondary combustion rate of CO and further release the chemical heat of molten iron, but because the reaction is carried out in the flue gas above the molten pool, a large amount of heat is taken away by the flue gas and transferred to the molten pool The thermal efficiency is very low, which also reduces the calorific value of the converter gas, and even makes the converter gas worthless to recover

[0006] The converter temperature-raising agents used by iron and steel enterprises are currently mainly carbon and silicon. The thermal efficiency of carbon-based temperature-raising agents is reduced, and the blowing time is prolonged; the silicon-based temperature-raising agents are oxidized to produce SiO 2 , reduces the alkalinity of the slag, and needs to increase the consumption of additional lime to balance the alkalinity of the slag, which also increases the consumption and cost of steel materials

[0007] Theoretically, the heat generated by oxidizing 1kg of iron can melt about 3kg of scrap steel to reach the tapping temperature. In order to eat more scrap steel, some converter steelmaking enterprises sacrifice the carbon index at the end point and raise the temperature of iron oxide materials, resulting in a large increase in cost, which is not worth the candle. Even the converter leakage accident caused by too high FeO in long-term slag