CN108165699B

CN108165699B - Operation method for converter temperature control slagging

Info

Publication number: CN108165699B
Application number: CN201711422033.5A
Authority: CN
Inventors: 吴明; 王军; 杨芳; 吕鸣
Original assignee: Maanshan Iron and Steel Co Ltd
Current assignee: Maanshan Iron and Steel Co Ltd
Priority date: 2017-12-25
Filing date: 2017-12-25
Publication date: 2020-09-04
Anticipated expiration: 2037-12-25
Also published as: CN108165699A

Abstract

The invention relates to the technical field of converter smelting, in particular to an operation method for converter temperature control slagging. By the operation method, the problems of large temperature fluctuation and molten steel splashing can not occur when the raw dolomite is put in; meanwhile, the raw dolomite is added by shaking, so that the problems of furnace bottom rising and the like can be well avoided.

Description

Operation method for converter temperature control slagging

Technical Field

The invention relates to the technical field of converter smelting, in particular to an operation method for converter temperature control slagging.

Background

The converter generally adopts the temperature-controlled slagging technology of adding light-burned dolomite in the smelting process, because the light-burned dolomite is formed by pre-calcining raw dolomite, the advantages are that the heat absorption of adding the converter is less, the slagging is fast, the blowing process is stable, but the price is 185 yuan per ton, especially the light-burned dolomite is transported for a long distance after being calcined, loaded and unloaded and then transmitted to a converter high-position bin through a belt to be added into the converter, the dust amount of the light-burned dolomite is about 30 percent of the total amount and is blown along the way and sucked away by a dust removal fan in the converter feeding process, the environment is polluted, the load of the fan is increased, the smelting slagging effect is not played, the utilization rate is low, and the use cost is high, so the light-burned dolomite is usually replaced by the; the main components of the raw dolomite are CaCO3 and MgCO3, which causes the raw dolomite to have large heat absorption capacity when being heated and decomposed, and the CaCO3 is CaO + CO2 delta H +178.3KJ/mol MgCO3 is MgO + CO2 delta H +100.59 KJ/mol; in the prior art, raw dolomite is added into a converter and is firstly calcined and decomposed into light-burned dolomite and then is melted into slag, which is a common technical means at present, but in the operation process, if improper control is caused, the early-stage temperature reduction is too large, and the later-stage temperature rise is caused, the violent gas discharge of the decomposition reaction is not smooth, so that the splashing accident is caused, and meanwhile, the excessive high-melting-point substance MgO after decomposition is easily adhered to the furnace bottom to cause the furnace bottom to rise and the like; therefore, a temperature-controlled slagging technique capable of solving the above problems is needed at present.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an operation method capable of being used for converter temperature control slagging.

In order to achieve the purpose, the invention adopts the technical scheme that:

an operation method for converter temperature control slagging comprises the following steps:

(1) measuring the content of silicon in the molten iron;

(2) determining the total mass of raw dolomite required by temperature control slagging;

(3) adding raw dolomite of which the mass is not more than one half of the total mass of the raw dolomite into a converter after slag splashing of converter tapping;

(4) after the step (3) is finished, calcining the raw dolomite into light-burned dolomite by utilizing the temperature in the hearth and removing corresponding gas;

(5) and (4) after the step (4) is basically finished, adding cold materials into the converter to perform iron adding operation, and performing converter blowing, wherein when the converter blowing is performed, the rest raw dolomite in the step (3) is put into the converter in batch mode until the rest raw dolomite is put in, the raw dolomite is put in, and the converter slagging operation is finished.

The granularity of the raw white stone in the step (2) is not more than 30 mm.

The proportion of each interval of the particle size of the raw white stone is 5mm-25mm, and is 85-92%; 25mm-30mm accounts for 1-10%; 0mm-5mm accounts for 5% -10%.

And (5) after the raw dolomite is added into the converter in the step (3) and the step (5), the converter is shaken by a converter driving device.

And (5) putting the raw dolomite into the converter in a batch continuous vibration feeding mode.

The raw dolomite is subjected to vibration type feeding through vibration equipment.

And (5) when the converter is blown, the raw dolomite is required to be put in within 12min from the beginning of oxygen blowing.

The oxygen supply amount during oxygen blowing is 2.1 ten thousand meters³Hour-2.5 ten thousand m³Time/hour.

The invention has the advantages that:

according to the invention, the problems of large temperature fluctuation and molten steel splashing can not occur when the raw dolomite is put in by controlling the putting amount and adopting multiple times of putting; meanwhile, the raw dolomite is added by shaking, so that the problems of furnace bottom rising and the like can be well avoided.

Detailed Description

The following description of preferred embodiments will provide further details of the present invention.

(1) measuring the content of silicon in the molten iron;

In the step (2), the granularity of the raw white stone is not more than 30 mm; can make the raw dolomite easier to be converted into light-burned dolomite, and preferably, the overall granularity interval of the invention is as follows: 5mm-25mm, accounting for 85-92%; 25mm-30mm accounts for 1-10%; 0mm-5mm accounts for 5% -10%.

Preferably, in the invention, after the raw dolomite is added into the converter in the step (3) and the step (5), the converter is shaken by a converter driving device, so that the bottom of the converter can be prevented from rising.

Preferably, the raw dolomite in the step (5) is thrown into the converter in a batch type continuous vibration feeding mode, the temperature drop in the early stage can be effectively controlled by adopting the feeding mode, and the problems that the spraying and slagging processes are difficult to control due to the fact that a large amount of decomposed gas is discharged in the later stage of the raw dolomite can be solved; in order to realize the continuous vibration feeding mode, the vibration equipment is adopted in the invention to realize the feeding mode, and the vibration equipment can be equipment such as a vibration mesh screen.

Preferably, in the step (5) of the invention, the raw dolomite is required to be completely put within 12min from the beginning of oxygen blowing when the converter is blown, so that the influence on the later converter blowing is avoided; the oxygen supply amount during simultaneous oxygen blowing is 2.1 ten thousand meters³Hour-2.5 ten thousand m³At one time, blowThe oxygen is divided into an early oxygen blowing period and a middle and later oxygen blowing period, wherein the oxygen supply amount at the early period is 2.1-2.2 ten thousand m 3/hour, and the oxygen supply amount at the middle and later periods is 2.2-2.5 ten thousand m 3/hour.

In the present invention, the specific implementation steps may be performed according to the following steps: the first choice requires that the raw dolomite components and the particle size meet the following requirements: the main components of the material are CaCO3 and MgCO3, after thermal decomposition, CaO content is more than or equal to 29.5MgO content is more than or equal to 19.5, SiO2 content is more than or equal to 2.5 granularity (mm), and the whole granularity interval accounts for the following ratio: 5mm-25mm, accounting for 85-92%; 25mm-30mm accounts for 1-10%; 5-10% of 0-5 mm; in the invention, a raw dolomite staged adding mode is adopted, after slag splashing of a converter, 1/2 raw dolomite can be added firstly, the raw dolomite is calcined into light-burned dolomite by utilizing the high temperature of a hearth, part of gas is removed, and then a cooling material is added for iron adding operation; meanwhile, the adding amount refers to the temperature of the molten iron and the silicon content in the molten iron, the raw dolomite can be put in according to the following table, and meanwhile, in order to prevent the raw dolomite from being accumulated at the bottom of the converter and being difficult to calcine, the converter is greatly shaken back and forth to disperse the raw burnt dolomite when the raw dolomite is added into the converter, so that the operation is favorable for calcining the raw burnt dolomite at high temperature into light burnt dolomite, and the generated decomposed gas is smoothly discharged, thereby further playing the role of rapid slagging.

The reference addition amount of the raw dolomite according to the silicon content of the molten iron is as follows:

in the invention, after the converter is used for iron adding and blowing, raw dolomite is added into the converter in a batch weighing continuous vibration feeding mode, the one-time feeding addition by centralized weighing of a gate valve is forbidden, the feeding speed is controlled between 120 kg and 200 kg per minute, and the operation can avoid the excessive temperature drop in the early stage and the orderly discharge of decomposition gas so as to control and reduce the occurrence of splashing; meanwhile, the addition of raw dolomite in the early stage of blowing in the converter is required to be finished before 12min of oxygen blowing when the feeding of raw dolomite in the blowing stage of the converter is finished, and the raw dolomite cannot be added after 12min, so that the influence on the whole converter blowing is avoided, certainly, if the temperature in the converter is high or slag needs to be adjusted, a small amount of raw dolomite can be continuously added according to the requirement, wherein the small amount of raw dolomite does not exceed 100kg, the oxygen supply amount in the early stage of blowing is 2.1-2.2 ten thousand m 3/per minute in the early stage of blowing, and the oxygen supply amount in the 6-15 minutes in the middle and later stages is 2.2-2.5 ten thousand m 3/minute, the lance position of the lance body for blowing oxygen in the early stage of blowing is 1.3-1.5 m, the lance position in the middle and later stages is 1.5-1.7 m, and the terminal pressure lance is 1.2m for 30 seconds, so that the converter blowing can be better carried out, and the MgO content in converter, the raw dolomite is prevented from being put in, and other substances are put in; meanwhile, the operation of 1.1 m at a low lance position is required to be adopted in the later stage of blowing, the stirring of a molten pool is enhanced for 1 min, and the rising of the converter bottom can be reduced to a certain extent.

It is clear that the specific implementation of the invention is not restricted to the above-described embodiments, but that various insubstantial modifications of the inventive process concept and technical solutions are within the scope of protection of the invention.

Claims

1. An operation method for converter temperature control slagging is characterized by comprising the following steps:

(1) measuring the content of silicon in the molten iron;

(5) after the step (4) is basically finished, adding cold charge and adding iron in the converter, and carrying out converter blowing, wherein when the converter blowing is carried out, the rest raw dolomite in the step (3) is put into the converter in batch mode until the rest raw dolomite is put in, the raw dolomite is put in, and the converter slagging operation is finished;

after the raw dolomite in the step (3) and the step (5) is added into the converter, the converter is shaken by a converter driving device;

putting raw dolomite in the step (5) into the converter in a batch continuous vibration feeding mode;

2. The operating method for temperature-controlled slagging of a converter according to claim 1, wherein the particle size of the raw dolomite in the step (2) is not more than 30 mm.

3. The operating method for temperature-controlled slagging of the converter according to claim 2, wherein the particle size of the raw dolomite accounts for 5mm to 25mm, 85% to 92%; more than 25mm and less than 30mm account for 1-10%; more than 0mm and less than 5mm account for 5-10 percent.

4. The method of claim 1, wherein the raw dolomite is fed by vibration equipment.

5. The method of claim 1, wherein the oxygen supply amount during oxygen blowing is 2.1 ten thousand meters³Hour-2.5 ten thousand m³Time/hour.