CN108277317B - method for improving yield of sinter by converter smelting - Google Patents

Abstract

the invention relates to a method for improving the yield of sinter by converter smelting, which comprises the following steps: 1) raw material operation; controlling the amount of hot metal charging water and the conditions of hot metal; 2) and (3) converter operation: controlling the addition amount of the sinter: when a bottom blowing converter is adopted, nitrogen is blown from the bottom for stirring; when a converter without bottom blowing is adopted, the gun is lowered to blow nitrogen; controlling the temperature drop of the sintered ore and preventing slag overflow; in order to avoid the phenomenon of slag drying back in the severe reaction period of carbon and oxygen, the lance position is improved in the middle stage of converting; and a slag stopping mark is added in advance during tapping to avoid later slag discharging. According to the invention, after the iron adding is finished, the sintered ore is supplemented through the converter high-level bin, the self-reduction reaction is firstly carried out by using a nitrogen stirring technology, and then oxygen is normally supplied for blowing, so that the yield of the sintered ore is improved; the method is simple and practical, is convenient to operate, has a very obvious reduction of the consumption index of the steel materials, and is beneficial to reducing the steel-making cost.

Description

Method for improving yield of sinter by converter smelting

Technical Field

the invention relates to the technical field of ferrous metallurgy, in particular to a method for improving the yield of sintered ore by converter smelting.

Background

at present, the steel scrap resources used in steel making in the metallurgical industry are quite short, and the situation of insufficient supply often occurs. In addition, when the crane is overhauled, the converter can not normally add the scrap steel, so the converter high-level bunker needs to be cooled to normally smelt the converter. The scrap steel is cooled at a high position, the scrap steel is processed into the granularity meeting the requirement, the storage and the material vibration of the storage bin can be facilitated, and the storage bin is easy to damage after being used for a long time; meanwhile, the high-level cooling scrap steel has higher processing cost than normal scrap steel, the cost needs to be reduced to the minimum in the face of the severe form of the current steel market, and the cost is directly increased by the converter high-level scrap steel.

according to the invention, the sinter replaces scrap steel to be added into the converter, so that friction of small scrap steel on a feeding belt and a storage bin of the converter is avoided, and a certain protection effect on equipment can be achieved; meanwhile, by using the nitrogen stirring technology, the yield of the sinter can be improved, the consumption of steel materials can be reduced, and the steel-making cost is reduced.

Disclosure of Invention

the invention provides a method for improving the yield of sinter in converter smelting, which comprises the steps of supplementing the sinter through a converter high-level bin after iron adding is finished, enabling the sinter to firstly perform self-reduction reaction by using a nitrogen stirring technology, and then normally supplying oxygen for blowing, thereby improving the yield of the sinter; the method is simple and practical, is convenient to operate, has a very obvious reduction of the consumption index of the steel materials, and is beneficial to reducing the steel-making cost.

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

a method for improving the yield of sinter by converter smelting comprises the following steps:

1) Raw material operation;

a) On the basis of meeting the requirement of the clearance of the molten iron tank, the iron charging amount is controlled to be more than 90 percent, and molten iron in front of the furnace is completely charged;

b) The molten iron condition is as follows: the silicon content of the molten iron is more than or equal to 0.30 percent and less than or equal to 0.60 percent, and the charging temperature of the molten iron is more than 1260 ℃;

2) The converter operation requirements are as follows:

a) After the iron adding of the converter is finished, the converter is shaken to a zero position, the total adding amount of the sinter is controlled to be 8-12 tons per furnace according to the temperature of the molten iron and the silicon content of the molten iron, and the sinter is added at one time:

b) after the sintered ore is added, when a bottom blowing converter is adopted, the mode of bottom blowing nitrogen is adjusted, and the nitrogen flow is 0.08-0.12 Nm³Stirring for more than 4min at the temperature of/t.min, and then returning to a normal smelting mode; when a converter without bottom blowing is adopted, the oxygen lance position is set to be 210-220 cm for blowing nitrogen, and the nitrogen flow is 48000Nm³after stirring for more than 30-60 seconds, setting the oxygen lance mode as a normal smelting mode, and reducing the lance to blow oxygen;

c) adding the slag making materials according to a conventional method, controlling the temperature drop of the sintering ore according to 19-21 ℃/t, wherein the temperature drop coefficient is 3 times that of common scrap steel;

d) Smelting oxygen blowing flow of 51000Nm³Over/h, for preventionstopping slag overflow, wherein the gun position at the early stage of converting is not more than 240 cm; meanwhile, 0.5-1 t of magnesite or light-burned dolomite is used as a slag pressing material, and when the slag reaches a furnace opening, the slag pressing material is added into the converter to break foam slag and prevent slag leakage;

e) in order to avoid the phenomenon of slag drying during the carbon-oxygen violent reaction period, the lance position is increased to 280-300 cm in the middle stage of converting, so that the mass fraction of FeO in the slag is kept at 14-20%, and the phosphorus and sulfur in the iron ore are removed; the oxygen blowing time is more than 14 min; carrying out process test after oxygen blowing;

f) and adding a slag blocking mark during tapping, and adding the slag blocking mark 30-60 s in advance by combining the clearance of the molten steel tank and the loading amount of the furnace, so as to avoid later slag falling.

the amounts of the sintered ore added are shown in the following table.

Temperature T of molten iron	silicon content Si of molten iron	amount of sinter added
			T≥1360℃	0.5％＜Si≤0.6％	10～12t
1360℃＞T≥1320℃	0.4％＜Si≤0.5％	9～10t
			1320℃＞T	0.3％≤Si≤0.4％	8t

Compared with the prior art, the invention has the beneficial effects that:

1) The sinter replaces scrap steel to be added into the converter, so that the condition that the converter steelmaking production is influenced due to insufficient scrap steel is reduced, and the production efficiency of the converter is improved;

2) The use of high-level cooling cold materials is avoided, the damage degree of the storage bin and the belt is reduced, the service life of the equipment is prolonged, and the maintenance cost is reduced;

3) the nitrogen stirring is utilized, so that the yield of the sinter can be improved, the consumption of steel and iron materials of the converter is reduced, and the production cost of steel making can be obviously reduced.

Detailed Description

The invention relates to a method for improving the yield of sintered ore by converter smelting, which is characterized by comprising the following steps:

1) Raw material operation;

a) on the basis of meeting the requirement of the clearance of the molten iron tank, the iron charging amount is controlled to be more than 90 percent, and molten iron in front of the furnace is completely charged;

b) The molten iron condition is as follows: the silicon content of the molten iron is more than or equal to 0.30 percent and less than or equal to 0.60 percent, and the charging temperature of the molten iron is more than 1260 ℃;

2) the converter operation requirements are as follows:

a) after the iron adding of the converter is finished, the converter is shaken to a zero position, the total adding amount of the sinter is controlled to be 8-12 tons per furnace according to the temperature of the molten iron and the silicon content of the molten iron, and the sinter is added at one time:

b) After the sintered ore is added, when a bottom blowing converter is adopted, the mode of bottom blowing nitrogen is adjusted, and the nitrogen flow is 0.08-0.12 Nm³stirring for more than 4min at the temperature of/t.min, and then returning to a normal smelting mode; when a converter without bottom blowing is adopted, the oxygen lance position is set to be 210-220 cm for blowing nitrogen, and the nitrogen flow is 48000Nm³after stirring for more than 30-60 seconds, setting the oxygen lance mode as a normal smelting mode, and reducing the lance to blow oxygen;

c) adding the slag making materials according to a conventional method, controlling the temperature drop of the sintering ore according to 19-21 ℃/t, wherein the temperature drop coefficient is 3 times that of common scrap steel;

d) smelting oxygen blowing flow of 51000Nm³over/h, in order to prevent slag overflow, the blowing earlier stage gunThe position is not more than 240 cm; meanwhile, 0.5-1 t of magnesite or light-burned dolomite is used as a slag pressing material, and when the slag reaches a furnace opening, the slag pressing material is added into the converter to break foam slag and prevent slag leakage;

e) in order to avoid the phenomenon of slag drying during the carbon-oxygen violent reaction period, the lance position is increased to 280-300 cm in the middle stage of converting, so that the mass fraction of FeO in the slag is kept at 14-20%, and the phosphorus and sulfur in the iron ore are removed; the oxygen blowing time is more than 14 min; carrying out process test after oxygen blowing;

f) And adding a slag blocking mark during tapping, and adding the slag blocking mark 30-60 s in advance by combining the clearance of the molten steel tank and the loading amount of the furnace, so as to avoid later slag falling.

2. the method for improving the yield of the sintered ore by converter smelting according to claim 1, wherein the addition amount of the sintered ore is shown in the following table.

Temperature T of molten iron	silicon content Si of molten iron	Amount of sinter added
			T≥1360℃	0.5％＜Si≤0.6％	10～12t
1360℃＞T≥1320℃	0.4％＜Si≤0.5％	9～10t
			1320℃＞T	0.3％≤Si≤0.4％	8t

The following examples are carried out on the premise of the technical scheme of the invention, and detailed embodiments and specific operation processes are given, but the scope of the invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[ examples ] A method for producing a compound

1) Raw material operation;

a) adding iron by adopting the upper limit of a hot metal ladle, controlling the iron adding amount to be more than 255 tons, completely adding molten iron in front of the ladle, and ensuring the loading amount of the molten iron to be more than 250 tons;

b) The molten iron condition is as follows: the silicon content of the molten iron is 0.30 percent, and the charging temperature of the molten iron is 1300 ℃;

2) The converter operation requirements are as follows:

a) after the iron adding of the converter is finished, the converter is shaken to a zero position, the total adding amount of the sinter is controlled to be 8 tons/furnace according to the temperature of the molten iron and the silicon content of the molten iron, and the sinter is added at one time;

b) After the addition of the sintered ore, when a bottom-blown converter is adopted, the bottom-blown mode is manually switched to 24 steps, and the nitrogen flow is 0.09Nm³Stirring for 4min at the temperature of/t.min, and then returning to a normal smelting mode;

when the converter without bottom blowing is adopted, the oxygen lance position is set to 210cm for blowing nitrogen, and the nitrogen flow is 48000Nm³After 30 seconds of nitrogen blow, selecting an oxygen lance mode as a 'smelting' mode and manually reducing the lance to blow oxygen;

c) The slag making material is added according to a conventional method, the temperature drop of the sintering ore is controlled according to 20 ℃/t, and the temperature drop coefficient is 3 times of that of the common scrap steel.

d) Smelting oxygen blowing flow of 51000Nm³H is used as the reference value. The flame is larger in the early stage of oxygen blowing, the oxygen content of iron ore is higher, the carbon-oxygen reaction in molten steel is more active, the phenomenon of more slag overflow is easily caused in the early stage of smelting, the slag condition is controlled by attention, and the early-stage gun position cannot be larger than 240 cm. Meanwhile, 0.5-1 t of magnesite is used as a slag pressing material, and when the slag reaches a furnace opening, the slag pressing material is added into the converter to break foam slag and prevent slag leakage;

In order to avoid the phenomenon of 'drying back' in the period of violent reaction of carbon and oxygen, the lance position is timely increased in the middle stage of smelting, so that the mass fraction of FeO in the slag is kept between 14 and 20 percent, and the phosphorus and the sulfur in the iron ore are continuously removed.

compared with the normal scrap feeding furnace number, the oxygen blowing time of the embodiment is shortened by 1 minute and 20 seconds, and the oxygen consumption is saved by 850Nm³The oxygen blowing time was 14min on average.

And a slag stopping mark is added during tapping, and the later slag discharging is avoided according to the clearance of the molten steel tank in a proper advance.

According to the invention, by adding the sintered ore before iron adding and then stirring by using nitrogen or bottom blowing argon, the phenomena of violent reaction and excessive smoke dust in the sintered ore furnace in the blowing process are avoided, the sintered ore is subjected to self-reduction reaction firstly, the slag is not active in the blowing process, the slag leakage phenomenon is avoided, and the environment is protected.

Comparing actual production, if the alloy addition amount is considered at the same time of molten iron blowing loss according to 10 percent, the yield of the sinter after stirring by using nitrogen or bottom blowing argon is 68.51 percent; the yield of the sintered ore before stirring without using inert gas was 50.14%. According to statistics of using units, the cost is saved by 225 ten thousand yuan in 2016 (1-6) months. And good economic benefit and social benefit are obtained.

the above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (2)

1. A method for improving the yield of sinter in converter smelting is characterized in that the sinter is supplemented through a converter high-level bin after iron adding is finished, self-reduction reaction is firstly carried out by using a nitrogen stirring technology, and then oxygen is normally supplied for blowing, so that the yield of the sinter is improved; the method comprises the following steps:

1) Raw material operation;

a) On the basis of meeting the requirement of the clearance of the molten iron tank, the iron charging amount is controlled to be more than 90 percent, and molten iron in front of the furnace is completely charged;

b) The molten iron condition is as follows: the silicon content of the molten iron is more than or equal to 0.30 percent and less than or equal to 0.60 percent, and the charging temperature of the molten iron is more than 1260 ℃;

2) the converter operation requirements are as follows:

a) After the iron adding of the converter is finished, the converter is shaken to a zero position, the total adding amount of the sinter is controlled to be 8-12 tons per furnace according to the temperature of the molten iron and the silicon content of the molten iron, and the sinter is added at one time:

b) after the sintered ore is added, when a bottom blowing converter is adopted, the mode of bottom blowing nitrogen is adjusted, and the nitrogen flow is 0.08-0.12 Nm³stirring for more than 4min at the temperature of/t.min, and then returning to a normal smelting mode; when a converter without bottom blowing is adopted, the oxygen lance position is set to be 210-220 cm for blowing nitrogen, and the nitrogen flow is 48000Nm³After stirring for more than 30-60 seconds, setting the oxygen lance mode as a normal smelting mode, and reducing the lance to blow oxygen;

c) adding the slag making materials according to a conventional method, and controlling the temperature drop of the sintering ore according to 19-21 ℃/t;

d) smelting oxygen blowing flow of 51000Nm³Over h, in order to prevent slag overflow, the lance position in the early stage of blowing is not more than 240 cm; meanwhile, 0.5-1 t of magnesite or light-burned dolomite is used as a slag pressing material, and when the slag reaches a furnace opening, the slag pressing material is added into the converter to break foam slag and prevent slag leakage;

e) in order to avoid the phenomenon of slag drying during the carbon-oxygen violent reaction period, the lance position is increased to 280-300 cm in the middle stage of converting, so that the mass fraction of FeO in the slag is kept at 14-20%, and the phosphorus and sulfur in the iron ore are removed; the oxygen blowing time is more than 14 min; carrying out process test after oxygen blowing;

f) and adding a slag blocking mark during tapping, and adding the slag blocking mark 30-60 s in advance by combining the clearance of the molten steel tank and the loading amount of the furnace, so as to avoid later slag falling.

2. the method for improving the yield of the sinter in converter smelting according to claim 1, wherein the addition amount of the sinter is shown in the following table

temperature T of molten iron Silicon content Si of molten iron Amount of sinter added T≥1360℃ 0.5％＜Si≤0.6％ 10～12t 1360℃＞T≥1320℃ 0.4％＜Si≤0.5％ 9～10t 1320℃＞T 0.3％≤Si≤0.4％ 8t

。