阅读说明：本技术 通过氧燃枪在铁包中预热废钢提高废钢比的冶炼方法 (Smelting method for improving scrap steel ratio by preheating scrap steel in iron ladle through oxygen combustion gun ) 是由 刘飞 邹长东 王耀 黄永林 陶向阳 皇祝平 于 2019-08-27 设计创作，主要内容包括：本发明公开了一种通过氧燃枪在铁包中预热废钢提高废钢比的冶炼方法,该方法具体为：兑完铁水后,铁水包由行车吊运至预热设备轨道,通过轨道将铁包送至加料位,由抓钢机将钢筋压块加入铁包。装料结束后将铁包运至加热位,下降燃烧枪和除尘烟罩,开始预热。预热结束后,将铁包运至吊包位,由行车将铁包吊上铁包车运至高炉接铁水,铁水兑入转炉开始吹炼,吹炼过程加入焦丁增加热量来源。本发明可提高转炉冶炼废钢比约6％,并解决转炉高废钢比冶炼热量不足的问题。(The invention discloses a smelting method for improving scrap steel ratio by preheating scrap steel in an iron ladle through an oxygen combustion gun, which comprises the following steps: after molten iron is added, the ladle is lifted to a track of preheating equipment by a crane, the ladle is conveyed to a feeding position through the track, and a steel bar pressing block is added into the ladle by a steel grabbing machine. After the charging is finished, the iron ladle is transported to a heating position, the combustion gun and the dust removal smoke hood are descended, and preheating is started. After preheating is finished, the ladle is transported to a ladle hanging position, the ladle is hung on a ladle car by a travelling crane and transported to a blast furnace to receive molten iron, the molten iron is added into the converter to start converting, and the coke is added in the converting process to increase the heat source. The invention can improve the scrap steel ratio of converter smelting by about 6 percent and solve the problem of insufficient smelting heat of the converter with high scrap steel ratio.)

1. A smelting method for improving the ratio of scrap steel by preheating the scrap steel in an iron ladle through an oxygen combustion gun is characterized in that: the method comprises the following steps:

s1: charging: filling scrap steel into the empty iron ladle after the molten iron is added, and controlling the loading amount of the scrap steel to be 4-8% of the tapping amount of the converter;

s2, preheating scrap steel: heating the empty iron ladle filled with the scrap steel for 3 minutes, and controlling the temperature of the scrap steel in the heated iron ladle to be 500-700 ℃;

s3, charging molten iron: molten iron is charged into the heated iron ladle, and the charging amount of the molten iron is 750kg per ton of steel;

and S4, adding into a converter: adding scrap steel into the converter, wherein the charging amount of the scrap steel is 20% of the tapping amount of the converter, and then adding the molten iron and the scrap steel in the iron ladle into the converter.

S5, adding nut coke and blowing: before the converter is started to blow, adding the coke dices at one time through a bin, wherein the adding amount of the coke dices is controlled to be 0-10 kg/t according to the temperature of molten iron and the silicon content.

2. The smelting method according to claim 1, wherein the scrap ratio is increased by preheating the scrap in the ladle through an oxygen combustion lance, characterized in that: in the step S1, the scrap steels mainly include steel bar briquettes and a small amount of loose material scrap steels, the size of the steel bar briquettes is not more than 600 × 600 × 800mm, the weight of a single briquette is not more than 1000kg, the loose material scrap steels mainly include i-steels, angle steels, channel steels and other industrial thin cut edges, and the length of the loose material scrap steels is not more than 500 mm.

3. The smelting method according to claim 1, wherein the scrap ratio is increased by preheating the scrap in the ladle through an oxygen combustion lance, characterized in that: in the step S2, the air iron ladle filled with the scrap steel is heated by an oxygen combustion gun, converter gas and oxygen are simultaneously sprayed from the oxygen combustion gun, the converter gas flow is 25-30 Nm 3/min/ton of steel, the oxygen flow is 8-10 Nm 3/min/ton of steel, and the air supply ratio of the converter gas to the oxygen is 3: 1.

4. The smelting method according to claim 1, wherein the scrap ratio is increased by preheating the scrap in the ladle through an oxygen combustion lance, characterized in that: in the step S5, when the amount of the iron water added into the converter is increased by 1 ton, the adding amount of the coke breeze can be reduced by 30-50 kg; when the addition of the scrap steel in the converter is reduced by 1 ton, the addition amount of the coke breeze can be reduced by 120-150 kg; when the cold-pressed balls are added for 500kg in the converter blowing process, the adding amount of the coke dices is required to be increased for 200-250 kg.

Technical Field

The application relates to the field of ferrous metallurgy, in particular to a smelting method for improving scrap steel ratio by preheating scrap steel in an iron ladle through an oxygen combustion gun.

Background

The steel scrap is a green resource in the steel industry, and the increase of the use amount of the steel scrap is an important way for reducing energy consumption and waste discharge in the steel industry. With the rapid development of the steel industry, the accumulated amount of steel in China is estimated to reach 100 hundred million tons at the end of 2020, the social production amount of steel scrap resources can reach 2 hundred million tons, and the steel scrap resources are gradually enriched. On the other hand, with the increasing of the implementation of the environmental protection method and the environmental supervision, the establishment of carbon emission trading systems all over the country, the popularization and implementation of high scrap steel ratio smelting, and the reduction of pollution emission and energy consumption become the most urgent tasks for the development of the steel industry. The improvement of the converter smelting scrap steel ratio is an important way for increasing the steelmaking yield, improving the production benefit and realizing low pollution and low emission under the condition of insufficient molten iron source.

The center of gravity of the prior art for improving the scrap steel ratio lies in solving two problems: one is how to add a large amount of scrap steel into the smelting process in a short time, and the other is how to solve the problem of insufficient heat caused by melting of a large amount of scrap steel. In the prior art, the two problems are generally solved by adding the scrap steel trough for multiple times and improving the tapping temperature of the blast furnace. However, the feeding of the scrap through the converter trough is limited by the size of the trough and the density of the scrap, the ratio of the single highest feeding to the waste is about 20%, and the process method adopting the multiple feeding of the trough seriously reduces the production efficiency. The method for solving the problem of insufficient heat caused by high scrap ratio by improving the temperature of the molten iron pushes the coke ratio of the blast furnace, increases the production cost and possibly causes unstable conditions of the blast furnace and influences the quality of the molten iron. Other modes of realizing continuous preheating of the steel scrap by reforming and adding equipment, preheating the steel scrap by recycling converter smoke and the like generally have the problems of large equipment one-time investment, high process technology difficulty, difficult maintenance, poor production stability and the like. Therefore, the search for a smelting method which is convenient to operate and low in cost and can improve the steel-to-scrap ratio of ton steel is a problem which needs to be solved urgently by a metallurgy worker at present.

Disclosure of Invention

The invention aims to provide a smelting method for improving the scrap ratio by preheating scrap steel in an iron ladle through an oxygen combustion gun, which can add the scrap steel into the iron ladle and completely melt the scrap steel in the molten iron receiving process of a blast furnace, has short time consumption in the process of adding the scrap steel into a converter and is not limited by the sizes of a scrap steel trough and a converter mouth. On the other hand, the method adopts the converter gas with low burning price to generate heat to preheat the waste steel, and adds the coke to supplement the heat source in the blowing process of the converter, thereby solving the problem of insufficient smelting heat with high waste steel ratio.

In order to achieve the purpose, the invention provides the following technical scheme:

a smelting method for improving the ratio of scrap steel by preheating the scrap steel in an iron ladle through an oxygen combustion gun comprises the following steps:

s1 charging: the empty iron ladle after being mixed with molten iron is adjusted to a scrap preheating equipment rail and moved to a charging position, a steel grabbing machine is adopted to load the scrap steel in a storage yard into the iron ladle, the time is 3-5 minutes, and the charging amount of the scrap steel is 4% -8% of the tapping amount of the converter;

preheating S2 scrap steel: after charging, transporting the iron ladle to a preheating position through a rail, descending a dust hood and an oxygen combustion gun to ventilate and preheat the scrap steel, wherein the preheating time is 3 minutes, and the temperature of the preheated scrap steel reaches 500-700 ℃;

s3 charging molten iron: after preheating of the scrap steel, transporting the iron ladle filled with the scrap steel to a blast furnace to be filled with molten iron, wherein the molten iron loading amount is 750kg per ton of steel;

s4, adding into a converter: after molten iron is filled in the blast furnace, the iron ladle is transported to a converter workshop, the molten iron is added into the converter, and before iron addition, non-preheated scrap steel is loaded through a material groove, wherein the loading amount is 20% of the tapping amount of the converter;

s5 blowing with a nut: before the converter is started to blow, the coke dices are added through a bin at one time, the adding amount of the coke dices is controlled to be 0-10 kg/t according to the temperature of molten iron and the silicon content, and a coolant can be added in the blowing process when the temperature is higher.

Preferably, in step S1, the preheated scrap steel is mainly steel bar briquettes with the size requirement of less than or equal to 600 × 600 × 800mm, the weight of a single ladle block is less than or equal to 1000kg, the briquettes are compact and do not scatter when falling to the ground, a small amount of loose scrap steel is added, the loading capacity of a single iron ladle is increased, i-steel, angle steel, channel steel and other industrial thin cut edges are mainly used, and the required length is less than or equal to 500 mm.

Preferably, in the step S2, in the scrap steel preheating process, converter gas and oxygen are simultaneously injected by a combustion gun, and the flow rate of the converter gas is 25-30 Nm³The flow rate of oxygen is 8-10 Nm/t steel³The ratio of the gas supply amount of the converter gas to the oxygen supply amount of the converter gas is 3: 1.

Preferably, in the step S5, in the converter coke-briquette blowing process, 30-50 kg coke briquette can be added less when 1t molten iron is added into the converter; when the adding amount of the scrap steel in the converter trough is reduced by 1t, 120-150 kg of small coke pieces can be added; 200-250 kg of coke pieces are added every 500kg of cold-pressed balls are added in the converter blowing process.

Compared with the prior art, the invention has at least the following beneficial effects:

1. the method has the advantages that the scrap steel is added into the iron ladle and completely melted in the process of receiving molten iron in the blast furnace, the time consumption in the process of adding the scrap steel into the converter is short, and the method is not limited by the sizes of a scrap steel trough and a converter mouth.

2. The invention adopts the converter gas with low combustion price to generate heat to preheat the waste steel, and adds the coke to supplement the heat source in the converter blowing process, thereby solving the problem of insufficient smelting heat of high waste steel ratio and having lower process cost.

3. The invention has the advantages of less equipment investment at one time, low process technology difficulty, simple maintenance, good production stability, high production efficiency and the like.

Detailed Description

The technical solutions in the embodiments of the present invention are described in detail below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.