阅读说明：本技术 一种提钒转炉和顶底复吹方法 (Vanadium extraction converter and top-bottom combined blowing method ) 是由 赵进宣 杨利彬 吴伟 杨勇 李相臣 于 2020-11-30 设计创作，主要内容包括：本发明涉及一种提钒转炉和顶底复吹方法,属于提钒转炉设备技术领域,解决了现有技术中提钒转炉护砖因炉内产生酸性渣而易于腐蚀,并且在高温下寿命缩短,无法实现大流量底吹的问题。本发明涉及的提钒转炉底吹元件,包括底吹护砖、三层同轴套管,所述三层同轴套管包括内管、中管、外管,内管通入惰性气体,中管通过可裂解的气体,外管通入惰性气体；顶吹氧枪,具有n个主孔,均匀分布,具有m个副孔,所述副孔位于主孔所在的面上,均匀分布于相邻主孔之间,n＝3-6,m＝n或2n。实现了含钒铁矿冶炼过程中,提钒转炉的大流量底吹。(The invention relates to a vanadium extraction converter and a top-bottom combined blowing method, belongs to the technical field of vanadium extraction converter equipment, and solves the problems that in the prior art, protective bricks of the vanadium extraction converter are easy to corrode due to acid slag generated in the converter, the service life is shortened at high temperature, and high-flow bottom blowing cannot be realized. The invention relates to a vanadium extraction converter bottom blowing element, which comprises a bottom blowing protective brick and three layers of coaxial sleeves, wherein the three layers of coaxial sleeves comprise an inner pipe, a middle pipe and an outer pipe, inert gas is introduced into the inner pipe, cleavable gas passes through the middle pipe, and the inert gas is introduced into the outer pipe; the top-blown oxygen lance is provided with n main holes which are uniformly distributed and m auxiliary holes, wherein the auxiliary holes are positioned on the surface of the main holes and uniformly distributed between the adjacent main holes, and n is 3-6, and m is n or 2 n. Realizes the large-flow bottom blowing of the vanadium extraction converter in the vanadium-containing iron ore smelting process.)

1. A vanadium extraction converter is characterized by comprising: a bottom blowing element and a top blowing oxygen lance;

the bottom blowing element comprises three layers of coaxial sleeves; the three-layer coaxial sleeve comprises an inner pipe, a middle pipe and an outer pipe, and is sleeved in the circular through hole of the bottom blowing protective brick; the inner pipe is an inert gas channel, a cleavable gas channel is arranged between the outer wall of the inner pipe and the inner wall of the middle pipe, and an inert gas channel is arranged between the inner wall of the outer pipe and the outer wall of the middle pipe;

the top-blown oxygen lance is provided with n main holes which are uniformly distributed, and m auxiliary holes which are uniformly distributed between the adjacent main holes and are positioned on the surface of the main holes, wherein n is 3-6, and m is n or 2 n.

2. The vanadium extraction converter according to claim 1, wherein the cleavable gas is methane.

3. The vanadium extraction converter according to claim 1, wherein the number of the bottom blowing elements is 3 to 6, the bottom blowing elements are uniformly distributed on the bottom of the converter, and the total flow rate of the bottom blowing is 0.06 to 0.5Nm³/min·t。

4. The vanadium extraction converter according to claim 1, wherein the bottom-blowing protective bricks are acid-resistant protective bricks made of silica.

5. The vanadium extraction converter as claimed in claim 1, wherein the bottom-blowing protection bricks are 200-500mm higher than the lining bricks at the periphery of the bottom of the converter.

6. The vanadium extraction converter according to claim 1, wherein the difference Δ D between the inner diameter of the outer pipe and the outer diameter of the middle pipe₁4-7mm, the difference Delta D between the inner diameter of the middle pipe and the outer diameter of the inner pipe₂3-4mm, the inner diameter of the inner tube Delta D₃＝4-6mm。

7. The vanadium extraction converter according to claim 3, wherein the total flow rate of the bottom blowing is 5 to 20Nm in gas flow rate between the inner wall of the outer tube and the outer wall of the middle tube³T, the gas flow between the outer wall of the inner tube and the inner wall of the middle tube is 0.8-5Nm³T, the gas flow rate of the inner tube is 5-10Nm³/h·t。

8. The vanadium extraction converter according to claim 1, characterized in that the molten iron in the vanadium extraction smelting comprises the following chemical components in percentage by mass: 4.01 to 4.2 percent of C, 0.22 to 0.25 percent of Si, 0.18 to 0.22 percent of Mn, 0.10 to 0.12 percent of P, 0.010 to 0.12 percent of S, 0.12 to 0.14 percent of Ti and 0.31 to 0.34 percent of V.

9. The vanadium extraction converter according to claim 1, wherein the vanadium slag formed by vanadium extraction smelting comprises the following chemical components in percentage by mass: SiO 2₂ 15-20％，CaO 4-5％，Cr₂O₃0.8-0.9％，V₂O₅ 18-21％，Fe 5-12％。

10. A top-bottom combined blowing method of a vanadium extraction converter, which is characterized in that the vanadium extraction converter of claims 1 to 9 is used for smelting in the vanadium extraction converter smelting process, and comprises the following steps:

step 1, 0-120 seconds after the start of converting, 2-3Nm of top-blown oxygen flow³T/min, 0.8-1.0m of oxygen lance position, and bottom blowing flow rate of 0.08-0.1Nm³/min·t；

Step 2, 121-³T/min, 1.0-1.2m of oxygen lance position, and 0.08-0.2Nm of bottom blowing flow³/min·t；

Step 3, 261-³T/min, 0.8-0.9m of oxygen lance position, and bottom blowing flow rate of 0.12-0.4Nm³/min·t。。

Technical Field

The invention relates to the technical field of vanadium extraction converter equipment, in particular to a vanadium extraction converter and a top-bottom combined blowing method.

Background

The top-bottom combined blowing is a revolutionary technology of the vanadium extraction and steel making technology of the converter, reaction kinetic conditions of molten steel in the converter are enhanced by using converter bottom blowing, the reaction speed is accelerated, and obvious effects are achieved on reducing the terminal carbon oxygen product of the converter, reducing the total iron of the final slag and accelerating the oxidation of impurities. In the case of stirring of a molten pool by blowing oxygen from the top of the converter, a stirring dead zone exists, so that the components and the temperature of the molten pool are uneven, the erosion of a furnace lining is also uneven, and the stirring dead zone is particularly prominent when the furnace volume ratio is increased in the later period of the furnace service. The top-bottom combined blowing process is produced in the seventies of the twentieth century, and after decades of experiments and practices, the top-bottom combined blowing process is basically mature, namely the converter performs top-blowing O at the top of the furnace in the smelting process₂The method is matched with the furnace bottom to blow inert gas to uniformly stir the molten pool, so that the reaction of the molten pool is close to balance, the quality of molten steel is improved, the cost of per ton of steel is reduced, the flexibility and the adaptability of the converter can be improved, and the capability of the converter for melting waste steel is improved, so that the amount of the waste steel entering the converter can be flexibly changed according to the price change of the waste steel and the molten iron in the market, and the economic benefit is obtained.

With the technology of converter slag splashing and protection, the service life of the converter is greatly improved, the arrangement form, the number, the structure and the material of the bottom blowing gas supply elements of the converter become the key for influencing the combined blowing of the whole converter, and the bottom gas supply elements are the technical core of the bottom blowing process. However, unlike the common iron ore for iron making, the vanadium-containing iron ore contains a large amount of vanadium, and in the converter, the vanadium is oxidized by the introduced oxygen to become vanadium slag precipitate, so that the slag amount in the vanadium extraction converter is larger, and the blockage is more easily caused.

The bottom blowing strength of the existing vanadium extracting converter is 0.02-0.06Nm³The difficulty of continuously improving the bottom blowing gas supply intensity of the converter is that: (1) the vanadium slag comprises the main chemical component of SiO in percentage by mass₂15-20％，CaO 4-5％，Cr₂O₃ 0.8-0.9％，V₂O₅18-21% of acid slag; (2) generally, three vanadium slags are left in the vanadium extraction furnace, and then slag pouring is carried out; (3) the vanadium extracting furnace has no slag splashing protection; (4) the furnace lining of the vanadium extraction furnace mainly comprises magnesium carbon and is seriously corroded by acid slag.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a vanadium extraction converter and a top-bottom combined blowing method, so as to solve the problems that the protective brick of the existing vanadium extraction converter is easy to corrode due to acid slag generated in the converter, the service life is shortened at high temperature, and large-flow bottom blowing cannot be realized.

In one aspect, the present invention provides a vanadium extraction converter, including: a bottom blowing element and a top blowing oxygen lance;

the bottom blowing element comprises three layers of coaxial sleeves; the three-layer coaxial sleeve comprises an inner pipe, a middle pipe and an outer pipe, and is sleeved in the circular through hole of the bottom blowing protective brick; the inner pipe is an inert gas channel, a cleavable gas channel is arranged between the outer wall of the inner pipe and the inner wall of the middle pipe, and an inert gas channel is arranged between the inner wall of the outer pipe and the outer wall of the middle pipe;

the top-blown oxygen lance is provided with n main holes which are uniformly distributed, and m auxiliary holes which are uniformly distributed between the adjacent main holes and are positioned on the surface of the main holes, wherein n is 3-6, and m is n or 2 n.

Further, the cleavable gas is methane.

Furthermore, the number of the bottom blowing elements is 3-6, the bottom blowing elements are uniformly distributed at the bottom of the converter, and the total flow of the bottom blowing is 0.06-0.5Nm³/min·t。

Further, the bottom blowing protection brick is made of silicon dioxide material and is acid-resistant.

Further, the bottom blowing protective bricks are 200-500mm higher than the furnace lining bricks at the periphery of the furnace bottom.

Further, the difference delta D between the inner diameter of the outer pipe and the outer diameter of the middle pipe₁4-7mm, the difference Delta D between the inner diameter of the middle pipe and the outer diameter of the inner pipe₂3-4mm, the inner diameter of the inner tube Delta D₃＝4-6mm。

Furthermore, in the total flow of the bottom blowing, the inner wall of the outer pipe and the outer wall of the middle pipeThe flow rate of the intermediate gas is 5-20Nm³T, the gas flow between the outer wall of the inner tube and the inner wall of the middle tube is 0.8-5Nm³T, the gas flow rate of the inner tube is 5-10Nm³/h·t。

Further, the molten iron in the vanadium extraction smelting comprises the following chemical components in percentage by mass: 4.01 to 4.2 percent of C, 0.22 to 0.25 percent of Si, 0.18 to 0.22 percent of Mn, 0.10 to 0.12 percent of P, 0.010 to 0.12 percent of S, 0.12 to 0.14 percent of Ti and 0.31 to 0.34 percent of V.

Further, the vanadium slag formed by vanadium extraction smelting comprises the following chemical components in percentage by mass: SiO 2₂ 15-20％，CaO 4-5％，Cr₂O₃ 0.8-0.9％，V₂O₅ 18-21％，Fe 5-12％。

In another aspect, the present invention provides a top-bottom combined blowing method for a vanadium extracting converter, wherein in the smelting of the vanadium extracting converter, the vanadium extracting converter according to claims 1 to 9 is used for smelting, and the method comprises:

step 1, 0-120 seconds after the start of converting, 2-3Nm of top-blown oxygen flow³T/min, 0.8-1.0m of oxygen lance position, and bottom blowing flow rate of 0.08-0.1Nm³/min·t；

Step 2, 121-³T/min, 1.0-1.2m of oxygen lance position, and 0.08-0.2Nm of bottom blowing flow³/min·t；

Step 3, 261-³T/min, 0.8-0.9m of oxygen lance position, and bottom blowing flow rate of 0.12-0.4Nm³/min·t。

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

(1) the main components of the vanadium slag comprise 15-20% of silicon dioxide, 18-21% of vanadium pentoxide, 4-5% of calcium oxide and 0.8-0.9% of chromium oxide, and the vanadium slag belongs to acid slag and has acid corrosivity for common bricks at high temperature. According to the invention, the material of the upper and lower protective bricks of the bottom-blowing element is changed into the acid-resistant protective brick made of silicon dioxide, so that the corrosion of vanadium slag on the bottom-blowing element can be effectively reduced.

(2) Through being three-layer sleeve pipe structure with the bottom blowing component design, let in the methane gas that can the schizolysis at sheathed tube well pipe, because methane gas can the schizolysis under high temperature, the schizolysis is endothermic reaction, and the schizolysis of schizolysis gas can absorb the heat, effectively reduces the temperature of bottom blowing component, avoids the long-time high temperature of bottom blowing component and the problem that the life-span seriously reduces, and the bottom blowing component life-span can reach more than ten thousand, compares in traditional bottom blowing component six thousand to seven thousand stoves and is showing the improvement.

(3) The brick protecting material of the bottom blowing element is selected from acid-resistant silicon dioxide and the cracking gas is introduced into the three-layer sleeve, so that the service life of the bottom blowing element is effectively prolonged, the problems of slag covering and erosion are solved, and high-flow bottom blowing is realized; the large-flow bottom blowing ensures that the stirring of a converter molten pool is more sufficient, uniform and rapid, improves the dynamic condition of element oxidation, improves the slagging condition and the vanadium slag component, can improve the oxidation rate and the slagging rate of vanadium, and can effectively reduce the loss of iron.

(4) The oxygen lance is provided with a plurality of auxiliary holes which are positioned on the surface of the main hole and are uniformly distributed around the main hole, so that the impact area of oxygen jet flow is increased, the contact area of vanadium in molten iron and oxygen airflow is promoted, and the oxidation efficiency of the vanadium in the molten iron is improved. Compared with the published CN106282481A, the auxiliary holes are positioned on the surface of the main hole, the blowing and jetting direction of the high-pressure oxygen is aligned to the surfaces of molten iron and slag in the furnace and does not act on the furnace wall lining, and the effect of the high-pressure oxygen on the furnace wall lining is avoided. Because the flow of the oxygen blown and jetted by the auxiliary holes is smaller than that of the main holes, most of the oxygen blown and jetted by the auxiliary holes is on the surfaces of molten iron and slag, and the completely oxidized carbon monoxide is oxidized in the oxidation process of the main holes, so that the reduction of the vanadium oxide is avoided.

In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1a is a top view of an oxygen lance structure with three main nozzles and three auxiliary holes.

FIG. 1b is a sectional view of the oxygen lance structure with three main nozzles and three auxiliary holes in the direction of A-A.

FIG. 2a is a top view of the structure of the oxygen lance with three main jet holes and six auxiliary holes.

FIG. 2b is a sectional view of the oxygen lance structure with three main nozzles and six auxiliary holes in the direction of A-A.

FIG. 3a is a top view of the structure of the oxygen lance with four main jet holes and four auxiliary holes.

FIG. 3b is a sectional view of the oxygen lance structure with four main nozzles and four auxiliary holes in the direction of A-A.

FIG. 3c is a sectional view of the lance structure B-B with four main nozzles and four auxiliary holes.

FIG. 4a is a top view of the structure of the oxygen lance with four main nozzles and eight auxiliary nozzles.

FIG. 4b is a sectional view of the oxygen lance structure with four main nozzles and eight auxiliary holes in the direction of A-A.

FIG. 4c is a sectional view of the oxygen lance structure B-B with four main nozzles and eight auxiliary holes.

Detailed Description

The following detailed description of the preferred embodiments of the invention is provided to illustrate the principles of the invention and not to limit the scope of the invention.

A top-bottom combined converting process, i.e. top-blowing O from the top of the converter during the smelting process₂The method is matched with the furnace bottom to blow inert gas to uniformly stir the molten pool, so that the reaction of the molten pool is close to balance, the quality of molten steel is improved, the cost of per ton of steel is reduced, the flexibility and the adaptability of the converter can be improved, and the capability of the converter for melting waste steel is improved, so that the amount of the waste steel entering the converter can be flexibly changed according to the price change of the waste steel and the molten iron in the market, and the economic benefit is obtained. Different from common iron ore ironmaking, the iron ore containing vanadium contains a large amount of vanadium, in a converter, the vanadium is oxidized by introduced oxygen to become vanadium slag precipitate, and the slag amount in the converter for extracting vanadium is larger, so that blockage is easily caused. The bottom blowing strength of the existing vanadium extracting converter is0.02-0.06Nm³The difficulty of continuously improving the bottom blowing gas supply intensity of the converter is that: (1) the vanadium slag comprises the main chemical component of SiO in percentage by mass₂ 15-20％，CaO 4-5％，Cr₂O₃ 0.8-0.9％，V₂O₅18-21% of acid slag; (2) generally, three vanadium slags are left in the vanadium extraction furnace, and then slag pouring is carried out; (3) the vanadium extracting furnace has no slag splashing protection; (4) the furnace lining of the vanadium extracting furnace mainly comprises magnesium and carbon, and the acid-collecting slag is seriously corroded.

Theoretical analysis and experiments show that the bottom blowing element adopts a three-layer coaxial sleeve type structure and is divided into an inner pipe, a middle pipe and an outer pipe. The inner pipe is used for introducing inert gas, the inert gas is also introduced between the inner wall of the outer pipe and the outer wall of the middle pipe, and methane which can be cracked is introduced between the inner wall of the middle pipe and the outer wall of the inner pipe. Methane has thermal instability at high temperature, can be cracked into carbon, hydrogen, ethylene and acetylene respectively at different temperatures, and the cracking reaction is an endothermic reaction, so that the working temperature of the bottom blowing element can be effectively reduced, and the service life of the bottom blowing element is prolonged.

Simultaneously, through analysis and research, SiO in the vanadium slag component₂ 15-20％，Cr₂O₃ 0.8-0.9％，V₂O₅18-21% of the acid protective brick has stronger corrosivity on the traditional magnesia carbon protective brick, and the acid protective brick made of silicon dioxide can effectively reduce the corrosion capability and the corrosion speed of vanadium slag, so that the acid protective brick made of silicon dioxide can effectively improve the corrosion resistance of the bottom blowing element to the vanadium slag and prolong the service life of the bottom blowing element.

The bottom blowing element adopts a three-layer coaxial sleeve type structure and acidic protective bricks made of silicon dioxide, so that the heat resistance and corrosion resistance of the bottom blowing element are effectively changed, the service life of the bottom blowing element is greatly prolonged, and high-flow bottom blowing is realized.

The invention provides a vanadium extraction converter, which comprises: a bottom blowing element and a top blowing oxygen lance;

the bottom blowing element comprises three layers of coaxial sleeves; the three-layer coaxial sleeve comprises an inner pipe, a middle pipe and an outer pipe, and is sleeved in the circular through hole of the bottom blowing protective brick; the inner pipe is an inert gas channel, a cleavable gas channel is arranged between the outer wall of the inner pipe and the inner wall of the middle pipe, and an inert gas channel is arranged between the inner wall of the outer pipe and the outer wall of the middle pipe;

the top-blown oxygen lance is provided with n main holes which are uniformly distributed and m auxiliary holes, wherein the auxiliary holes are positioned on the surface of the main holes and uniformly distributed between the adjacent main holes, and n is 3-6, and m is n or 2 n; the central included angle of the main hole is 10-15 degrees, and the central included angle of the auxiliary hole is the same as the central included angle of the main hole, as shown in fig. 1 and fig. 2.

The oxygen lance is provided with a main hole and an auxiliary hole, wherein the main hole blows oxygen at a large flow rate to drive oxygen into molten steel and stir the oxygen to promote oxidation of impurities in the lance, and the auxiliary hole adopts a small flow rate to mainly blow oxygen on the surfaces of the molten steel and slag. The blowing and jetting direction of the auxiliary holes adopted in the prior art is lateral and is not in the same direction with the main holes, and a great deal of research of the inventor finds that high-pressure oxygen blown and jetted laterally is directly blown and jetted on the furnace wall and the furnace lining, the furnace is high in temperature in the blowing process, molten iron and slag are corroded in the furnace, and the auxiliary holes are easily damaged and deformed under the blowing and jetting of the oxygen. The blowing and jetting direction of the auxiliary holes is the same as that of the main holes, and the auxiliary holes face to the bottom surface of the furnace bottom and are blown and jetted on molten iron and slag, so that the damage and the influence on the furnace wall and the furnace lining are avoided.

The high-pressure oxygen of the main hole is injected into the molten iron in the furnace in a gas column mode, so that the oxygen above the molten iron is unevenly distributed, the auxiliary holes are evenly distributed around the main hole, the uniformity of the oxygen above the molten iron is effectively improved, the whole molten iron is covered by an oxygen layer, the molten iron and the slag are wrapped and immersed by oxygen atmosphere, the oxidation of vanadium is facilitated, and the oxidation rate of the vanadium is improved. Meanwhile, the oxygen blown by the auxiliary holes can oxidize reducing gases such as carbon monoxide generated by insufficient oxidation in the furnace, so that the reduction of the oxidation rate of vanadium caused by the reduction of the oxidized vanadium by the reducing gases is prevented.

Specifically, the diameter of the main hole is d₂40-55mm, and the Mach number of the blown oxygen is 1.95-2.05; the aperture of the secondary pore is d₃8-15mm, and the Mach number of the blown oxygen gas is 1.

Considering different functions with the main hole, the aperture and the Mach number of the secondary hole have special requirements, and the excessive aperture and the excessive Mach number of the secondary hole can cause oxygen to flow out of the secondary holeThe flow of the main hole is influenced, so that the oxygen blown into the molten steel by the main hole is insufficient, the stirring effect of the oxygen on the molten steel is reduced, and the oxidation rate of vanadium is seriously influenced. If the aperture and the Mach number of the secondary holes are too small, the secondary holes cannot effectively blow and jet oxygen, an oxygen layer cannot be formed on the surfaces of molten iron and slag, and the reducing gas in the furnace cannot be sufficiently oxidized. Thus, the secondary pores have a pore diameter d₃8-15mm, and the Mach number of the blown oxygen gas is 1.

Specifically, the central included angle of the main hole is 10-15 degrees, and the central included angle of the auxiliary hole is the same as the central included angle of the main hole. It should be noted that the center included angle of the main hole and the center included angle of the secondary hole mentioned in the present application refer to the included angle between the axis of the main hole and the central axis of the oxygen lance and the included angle between the axis of the secondary hole and the central axis of the oxygen lance, respectively.

The openings of the auxiliary holes in the prior art are positioned on the side wall, the openings of the auxiliary holes and the main holes are positioned on the same surface and are positioned on the bottom surface, and the central included angle of the auxiliary holes is lower than 30 degrees. Because the auxiliary holes are positioned between the adjacent main holes, the central included angle of the auxiliary holes is the same as that of the main holes and can be 10-15 degrees. The angle can ensure that oxygen blown out from the auxiliary hole does not act on the furnace wall, the structure of the furnace wall is not influenced, and meanwhile, the oxygen of the auxiliary hole acts on molten steel and slag.

In particular, the cleavable gas is methane.

It should be noted that methane has a more complex cracking process, and temperature is the most important factor affecting cracking: when the temperature reaches 927.8K, methane can be cracked into carbon black and hydrogen; when the temperature reaches 1709.4K, the reaction of cracking into ethylene occurs; when the temperature reaches 1866K, the reaction of cracking to acetylene can take place. Because methane can take place the pyrolysis reaction when 927.8K, can carry out the heat through the pyrolysis reaction and absorb, prevent effectively that the bottom blowing component temperature is too high, realize the high temperature protection of bottom blowing component.

Specifically, the number of bottom blowing elements is 3-6, the bottom blowing elements are uniformly distributed at the bottom of the converter, and the total flow rate of bottom blowing is 0.06-0.5Nm³/min·t。

Considering that bottom blowing is used for realizing rapid stirring of molten iron in the furnace, the oxidation of vanadium in the molten iron is accelerated to become vanadium slag by matching with top blowing, and the removal of silicon element in the molten iron is accelerated to become slag, so that the optimal position of arranging a bottom blowing element on the furnace bottom is the center of the furnace bottom. However, a bottom-blowing element located in the center of the hearth can only provide good stirring in the central axial region of the converter, and can hardly provide gas stirring action around the periphery of the converter. If two bottom blowing elements are arranged at the bottom of the converter, the two bottom blowing elements are symmetrically distributed in the radial direction of the central axis of the converter, and gas stirring can hardly be provided for molten steel in the radial area of the non-bottom blowing elements. In order to realize the uniformity of gas stirring in the furnace, at least three bottom blowing elements are arranged at the bottom of the furnace, and at most 6 bottom blowing elements are uniformly arranged at the bottom of the furnace in consideration of cost control and the difficulty of later maintenance of equipment.

Specifically, the bottom-blowing protective brick of the bottom-blowing element is an acid-resistant protective brick made of silicon dioxide.

Because the furnace lining of the vanadium extraction converter mostly adopts carbon magnesium, vanadium and silicon in the converter do not generate slag splash after being oxidized by the top-blowing oxygen lance, but are attached to the bottom of the converter, the vanadium slag can be contacted with the bottom-blowing element for a long time, the bottom-blowing element can be corroded, the service life of the bottom-blowing element is further shortened, and even the bottom-blowing element is damaged. Through theoretical verification and test, the protective brick made of the silicon dioxide material can not only effectively bear the high temperature in the converter, but also generate certain corrosion resistance to the slag. Therefore, the bottom blowing protective bricks of the bottom blowing element are made of the acid-resistant protective bricks made of silicon dioxide, so that the corrosion resistance of the bottom blowing element is improved, and the service life of the bottom blowing element is prolonged.

In one possible embodiment, the bottom-blowing protection bricks are arranged 200-500mm higher than the lining bricks at the periphery of the bottom of the furnace.

As mentioned above, the lining of the vanadium extraction converter is mostly made of carbon magnesium, vanadium and silicon in the converter are oxidized by the top-blown oxygen lance, slag splashing is not generated, the vanadium and silicon in the converter are attached to the bottom of the converter, the bottom-blown element is flush with the bottom of the converter and can be covered by slag, so that blockage is caused, bottom-blown gas cannot be blown into the converter through a normal air passage, and even gas of the bottom-blown element is blown into the converter along a gap at the edge, so that structural damage to the bottom of the converter is caused. Therefore, the bottom-blowing protective bricks are higher than the furnace lining bricks at the periphery of the furnace bottom. Through tests and calculation, the height of the bottom-blowing protection brick higher than the furnace lining brick is related to the vanadium slag content in the furnace and the dumping frequency of the vanadium slag, and finally the arrangement of the bottom-blowing protection brick at the furnace bottom brick is determined to be 200-500mm higher than the furnace lining brick at the periphery.

Specifically, the difference Δ D between the inner diameter of the outer pipe and the outer diameter of the middle pipe₁4-7mm, difference delta D between inner diameter of middle pipe and outer diameter of inner pipe₂3-4mm, inner diameter of inner tube DeltaD₃＝4-6mm。

It should be noted that the middle pipe is fed with methane gas which is easy to crack, and the methane gas is not excessive, so that the difference Delta D between the inner diameter of the middle pipe and the outer diameter of the inner pipe₂Should be as small as possible, the outer diameter D2 of the middle pipe and the outer diameter D3 of the inner pipe should be close to each other, namely Delta D₂3-4 mm. The inert gas is mainly blown in by bottom blowing and is mainly combined with top blowing to stir molten steel in the converter and promote slag formation, so the inner diameter delta D of the inner pipe responsible for bottom blowing of the inert gas₃And the difference Delta D between the inner diameter of the outer pipe and the outer diameter of the middle pipe₁Should be greater than Δ D₂. Therefore, the difference Δ D between the inner diameter of the outer pipe and the outer diameter of the middle pipe₁4-7mm, difference delta D between inner diameter of middle pipe and outer diameter of inner pipe₂3-4mm, inner diameter of inner tube DeltaD₃4-6 mm. In one possible embodiment, the outer diameter D1 of the outer tube is 20 to 35mm and the wall thickness is 2mm, the outer diameter D2 of the middle tube is 15 to 19mm and the wall thickness is 2mm, and the outer diameter D3 of the inner tube is 8 to 14mm and the wall thickness is 2 mm.

Specifically, in the total flow rate of the bottom-blowing, the gas flow rate between the inner wall of the outer tube and the outer wall of the middle tube is 5 to 20Nm³T, the gas flow between the outer wall of the inner tube and the inner wall of the middle tube is 0.8-5Nm³T, the gas flow rate of the inner tube is 5-10Nm³/h·t。

It is important to note that the bottom blowing flow of the triple coaxial sleeves of the bottom blowing element needs to be very tightly controlled. Inert gas is introduced into the outer pipe and the inner pipe, molten steel in the converter is stirred and slagging is promoted by the cooperation of bottom blowing inert gas and top blowing, so that the flow rate is relatively high, and the gas flow rate between the inner wall of the outer pipe and the outer wall of the outer pipe is set to be 5-20Nm according to the pipe diameters of the outer pipe and the inner pipe³T, the flow rate of the inner pipe is 5-10Nm³H.t. Different from the outer pipe and the inner pipe, the cracked methane gas is introduced between the outer wall of the inner pipe and the inner wall of the inner pipe, and the methane gas is crackedThen generating impurity gases including hydrogen, ethylene and acetylene. If the flow rate of the methane gas is too large, the methane gas cannot be split to desorb heat, which causes waste, and more seriously, the methane gas and oxygen in the top-blown converter are mixed, and if the methane gas reaches the explosion limit, the danger of explosion may be caused under the high-temperature condition of the converter. Even if methane can be cracked sufficiently, cracked impurity gases such as hydrogen, ethylene and acetylene can be mixed with oxygen, and the danger of explosion is easy to occur. Therefore, the flow rate of the gas introduced between the outer wall of the bottom-blowing inner tube and the inner wall of the middle tube must be strictly controlled, and the flow rate should be as small as possible to ensure that the methane gas before cracking or the impurity gas after cracking do not have the risk of explosion due to the content being too high to reach the explosion limit of the mixture with oxygen. Therefore, the gas flow between the outer wall of the inner pipe and the inner wall of the middle pipe is controlled not to be higher than 5Nm³H.t. Meanwhile, the gas flow between the outer wall of the inner pipe and the inner wall of the inner pipe is too small to cause the cracking gas content to be too small to effectively generate cracking absorption heat in time, the bottom blowing element is cooled, meanwhile, the gas flow between the outer wall of the inner pipe and the inner wall of the inner pipe is too low to easily cause vanadium slag covering to cause blockage, and through a large number of tests, the gas flow between the outer wall of the inner pipe and the inner wall of the inner pipe is set to be not lower than 0.8Nm³H.t. Therefore, the gas flow rate between the outer wall of the inner pipe and the inner wall of the middle pipe is 0.8-5Nm³/h·t。

The invention also relates to a vanadium extraction converter, which uses the bottom blowing element for molten iron vanadium extraction smelting, wherein the molten iron comprises the following chemical components in percentage by mass: 4.01 to 4.2 percent of C, 0.22 to 0.25 percent of Si, 0.18 to 0.22 percent of Mn, 0.10 to 0.12 percent of P, 0.010 to 0.12 percent of S, 0.12 to 0.14 percent of Ti and 0.31 to 0.34 percent of V.

Considering that the vanadium content and the silicon content in the molten iron directly influence the slag generation amount and excessive slag can cause corrosion, blockage and other influences on bottom blowing elements to realize large-flow bottom blowing, the Si content is required to be controlled to be 0.22-0.25%, and the V content is required to be controlled to be 0.31-0.34%.

Specifically, the vanadium extraction converter is used for extracting vanadium from molten iron for smelting, and the vanadium slag formed in the vanadium extraction smelting comprises the chemical component of SiO in percentage by mass₂ 15-20％，CaO 4-5％，Cr₂O₃ 0.8-0.9％，V₂O₅ 18-21％，Fe 5-12％。

Through large-flow bottom blowing, the iron content of the slag is greatly reduced in the process of extracting vanadium from molten iron and forming slag, and the iron content is 5-12% through tests.

The invention relates to a top-bottom combined blowing method for extracting vanadium, which uses the top-blowing oxygen lance to blow in the smelting of a vanadium extracting converter and comprises the following steps:

step 1, 0-120 seconds after the start of converting, 2-3Nm of top-blown oxygen flow³T/min, 0.8-1.0m of oxygen lance position, and bottom blowing flow rate of 0.08-0.1Nm³/min·t；

Step 2, 121-³T/min, 1.0-1.2m of oxygen lance position, and 0.08-0.2Nm of bottom blowing flow³/min·t；

Step 3, 261-³T/min, 0.8-0.9m of oxygen lance position, and bottom blowing flow rate of 0.12-0.4Nm³/min·t。

The bottom blowing method realizes large-flow bottom blowing, the service life of a bottom blowing element can reach more than ten thousand furnaces, and the service life of the bottom blowing element is obviously prolonged compared with that of six thousand to seven thousand furnaces of the traditional bottom blowing element. The iron content in the vanadium slag is effectively controlled.

Example 1

A vanadium extraction converter and a top-bottom combined blowing method.

The bottom blowing element comprises three layers of coaxial sleeves, nitrogen is introduced into the inner pipe, methane gas is introduced between the inner wall of the middle pipe and the outer wall of the inner pipe, and nitrogen is introduced between the inner wall of the outer pipe and the outer wall of the middle pipe. Difference Delta D between inner diameter of outer pipe and outer diameter of middle pipe₁4mm, difference DeltaD between inner diameter of middle pipe and outer diameter of inner pipe₂4mm, inner diameter Δ D of the inner tube₃6 mm. The outer diameter D1 of the outer tube is 26mm, and the wall thickness is 2 mm; the outer diameter D2 of the middle pipe is 18mm, and the wall thickness is 2 mm; the inner tube has an outer diameter D3 of 10mm and a wall thickness of 2 mm. The corresponding bottom blowing flow rate is: outer tube 8Nm³T, 0.8Nm of middle tube³T, inner tube 6Nm³/h·t。

The bottom blowing protection brick is made of silicon dioxide material and is acid-resistant. The arrangement of the bottom-blowing bricks on the bottom bricks is 200mm higher than the peripheral furnace lining bricks.

The number of the bottom blowing elements is three, and the bottom blowing elements are uniformly distributed on the bottom of the furnace.

The top-blown oxygen lance main hole is provided with 3 holes, the aperture is 40mm, the Mach number is 2.01, 3 auxiliary holes are arranged around the main hole, the aperture is 8mm, and the Mach number is 1.

The vanadium extraction top-bottom combined blowing method comprises the following steps: 0-120 seconds, and the oxygen flow rate is controlled to be 2.2Nm³T/min, lance position of the oxygen lance is 0.85m, bottom blowing flow is 0.08Nm³Min. t; at 121-³T/min, oxygen lance position 1.1m, bottom blowing flow 0.08Nm³Min. t; 261 ℃ and 280 seconds, the oxygen flow rate is 1.8Nm³T/min, lance position of the oxygen lance is 0.8m, bottom blowing flow is 0.12Nm³And/min. t, finishing converting.

The molten iron of the vanadium extraction furnace comprises, by mass, 4.01% of C, 0.22% of Si, 0.18% of Mn0.10% of P, 0.10% of S, 0.12% of Ti and 0.32% of V.

The chemical component of the vanadium slag of the converter is SiO in percentage by mass₂ 18％，CaO 4.2％，Cr₂O₃ 0.82％，V₂O₅18.8％，M.Fe 6.8％。

Example 2

A vanadium extraction converter and a top-bottom combined blowing method.

The bottom blowing element comprises three layers of coaxial sleeves, nitrogen is introduced into the inner pipe, methane gas is introduced between the inner wall of the middle pipe and the outer wall of the inner pipe, and nitrogen is introduced between the inner wall of the outer pipe and the outer wall of the middle pipe. And nitrogen is introduced between the inner wall of the outer pipe and the outer wall of the middle pipe. Difference Delta D between inner diameter of outer pipe and outer diameter of middle pipe₁5mm, difference DeltaD between inner diameter of middle pipe and outer diameter of inner pipe₂3mm, inner diameter of inner tube Δ D₃4 mm. The outer diameter D1 of the outer tube is 24mm, and the wall thickness is 2 mm; the outer diameter D2 of the middle pipe is 15mm, and the wall thickness is 2 mm; the inner tube has an outer diameter D3 of 8mm and a wall thickness of 2 mm. The corresponding bottom blowing flow rate is: outer tube 12Nm³T, middle tube 1Nm³T, inner tube 9Nm³/h·t。

The bottom blowing protection brick is made of silicon dioxide material and is acid-resistant. The arrangement of the bottom-blowing bricks on the bottom bricks is 300mm higher than the peripheral furnace lining bricks.

The number of the bottom blowing elements is four, and the bottom blowing elements are uniformly distributed on the bottom of the furnace.

The top-blown oxygen lance main hole is provided with 3 holes, the aperture is 45mm, the Mach number is 1.99, 6 auxiliary holes are arranged around the main hole, the aperture is 10mm, and the Mach number is 1.

The vanadium extraction top-bottom combined blowing method comprises the following steps: 0-120 seconds, and the oxygen flow rate is controlled to be 2.3Nm³T/min, 0.9m of oxygen lance position, 0.09Nm of bottom blowing flow³Min. t; at 121-³T/min, oxygen lance position 1.2m, bottom blowing flow 0.11Nm³Min. t; 261 ℃ and 280 seconds, the oxygen flow rate is 2.1Nm³T/min, 0.8m of oxygen lance position, 0.2Nm of bottom blowing flow³And/min. t, finishing converting.

The molten iron of the vanadium extraction furnace comprises, by mass, 4.11% of C, 0.23% of Si, 0.20% of Mn0.11% of P, 0.11% of S, 0.13% of Ti and 0.32% of V.

The chemical component of the vanadium slag of the converter is SiO in percentage by mass₂ 20％，CaO 4.1％，Cr₂O₃ 0.83％，V₂O₅20％，M.Fe 7.2％。

Example 3

A vanadium extraction converter and a top-bottom combined blowing method.

The bottom blowing element comprises three layers of coaxial sleeves, nitrogen is introduced into the inner pipe, methane gas is introduced between the inner wall of the middle pipe and the outer wall of the inner pipe, and nitrogen is introduced between the inner wall of the outer pipe and the outer wall of the middle pipe. And nitrogen is introduced between the inner wall of the outer pipe and the outer wall of the middle pipe. Difference Delta D between inner diameter of outer pipe and outer diameter of middle pipe₁6mm, difference DeltaD between inner diameter of middle pipe and outer diameter of inner pipe₂6mm, inner diameter of inner tube Δ D₃4 mm. The outer diameter D1 of the outer tube is 28mm, and the wall thickness is 2 mm; the outer diameter D2 of the middle pipe is 18mm, and the wall thickness is 2 mm; the inner tube has an outer diameter D3 of 8mm and a wall thickness of 2 mm. The corresponding bottom blowing flow rate is: outer tube 16Nm³T, 2Nm of middle tube³T, inner tube 7Nm³/h·t。

The bottom blowing protection brick is made of silicon dioxide material and is acid-resistant. The arrangement of the bottom-blowing bricks on the furnace bottom bricks is 400mm higher than the peripheral furnace lining bricks.

The number of the bottom blowing elements is five, and the bottom blowing elements are uniformly distributed on the bottom of the furnace.

The top-blown oxygen lance main hole is provided with 4 holes with the aperture of 50mm and the Mach number of 1.99, and 4 auxiliary holes with the aperture of 12mm and the Mach number of 1 are arranged around the main hole.

The vanadium extraction top-bottom combined blowing method comprises the following steps: 0-120 seconds, and the oxygen flow rate is controlled to be 2.5Nm³T/min, lance position of the oxygen lance is 0.8m, bottom blowing flow is 0.08Nm³Min. t; at 121-³T/min, oxygen lance position 1.0m, bottom blowing flow 0.13Nm³Min. t; 261 ℃ and 280 seconds, the oxygen flow rate is 2.2Nm³T/min, lance position of the oxygen lance is 0.8m, bottom blowing flow is 0.25Nm³And/min. t, finishing converting.

The molten iron of the vanadium extraction furnace comprises, by mass, 4.19% of C, 0.24% of Si, 0.22% of Mn0.12% of P, 0.12% of S, 0.14% of Ti and 0.34% of V.

The chemical component of the vanadium slag of the converter is SiO in percentage by mass₂ 20％，CaO 4.5％，Cr₂O₃ 0.89％，V₂O₅21％，M.Fe 5.2％。

Example 4

A vanadium extraction converter and a top-bottom combined blowing method.

The bottom blowing element comprises three layers of coaxial sleeves, nitrogen is introduced into the inner pipe, methane gas is introduced between the inner wall of the middle pipe and the outer wall of the inner pipe, and nitrogen is introduced between the inner wall of the outer pipe and the outer wall of the middle pipe. And nitrogen is introduced between the inner wall of the outer pipe and the outer wall of the middle pipe. Difference Delta D between inner diameter of outer pipe and outer diameter of middle pipe₁6mm, difference DeltaD between inner diameter of middle pipe and outer diameter of inner pipe₂3mm, inner diameter of inner tube Δ D₃7 mm. The outer diameter D1 of the outer tube is 28mm, and the wall thickness is 2 mm; the outer diameter D2 of the middle pipe is 18mm, and the wall thickness is 2 mm; the inner tube has an outer diameter D3 of 11mm and a wall thickness of 2 mm. The corresponding bottom blowing flow rate is: outer tube 20Nm³T, middle tube 4Nm³T, inner tube 6Nm³/h·t。

The bottom blowing protection brick is made of silicon dioxide material and is acid-resistant. The arrangement of the bottom blowing bricks on the furnace bottom bricks is 500mm higher than the peripheral furnace lining bricks.

Six bottom blowing elements are uniformly distributed on the bottom of the furnace.

The top-blown oxygen lance main hole is provided with 4 holes, the aperture is 55mm, the Mach number is 1.98, 8 auxiliary holes are arranged around the main hole, the aperture is 15mm, and the Mach number is 1.

The vanadium extraction top-bottom combined blowing method comprises the following steps: 0-120 seconds, and the oxygen flow rate is controlled to be 2.2Nm³T, 1.0m of oxygen lance position, 0.1Nm of bottom blowing flow³Min. t; at 121-³T/min, 1.2m of oxygen lance position, 0.18Nm of bottom blowing flow³Min. t; 261 ℃ and 280 seconds, the oxygen flow rate is 2.5Nm³T/min, lance position of the oxygen lance is 0.9m, bottom blowing flow is 0.3Nm³And/min. t, finishing converting.

The molten iron of the vanadium extraction furnace comprises, by mass, 4.11% of C, 0.24% of Si, 0.19% of Mn0.10% of P, 0.11% of S, 0.13% of Ti and 0.32% of V.

The chemical component of the vanadium slag of the converter is SiO in percentage by mass₂ 18％，CaO 4.3％，Cr₂O₃ 0.83％，V₂O₅19％，M.Fe 7.3％。

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 changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.