阅读说明：本技术 一种低硅含钒铁水提钒方法 (Method for extracting vanadium from low-silicon vanadium-containing molten iron ) 是由 肖峰 徐瑜 罗清明 闵荣浑 毛晓斌 于 2020-12-11 设计创作，主要内容包括：本发明公开一种低硅含钒铁水提钒方法,所述方法包括将铁水加入转炉中进行吹炼提钒,在提钒中期加入多孔二氧化硅,所述多孔二氧化硅为球状颗粒,平均粒径为0.5-1mm,多孔二氧化硅加入量为2-10kg/吨铁水。进一步的,所述提钒方法还包括在提钒前期加入石灰粉,所述石灰粉的加入量为10-30kg/吨铁水。多孔二氧化硅可助力钒氧化,增加钒渣中V-2O-5含量,石灰粉能促进磷氧化朝正方向发展,使铁水脱磷更彻底。(The invention discloses a method for extracting vanadium from low-silicon vanadium-containing molten iron, which comprises the steps of adding the molten iron into a converter for converting and extracting vanadium, and adding porous silicon dioxide in the middle stage of vanadium extraction, wherein the porous silicon dioxide is spherical particles, the average particle size is 0.5-1mm, and the adding amount of the porous silicon dioxide is 2-10 kg/ton of molten iron. Further, the vanadium extraction method also comprises the step of adding lime powder at the early stage of vanadium extraction, wherein the adding amount of the lime powder is 10-30 kg/ton of molten iron. The porous silicon dioxide can assist vanadium oxidation and increase V in vanadium slag 2 O 5 The lime powder can promote the phosphorus oxidation to develop towards the positive direction, so that the molten iron dephosphorize more thoroughly.)

1. A method for extracting vanadium from low-silicon vanadium-containing molten iron comprises the steps of adding the molten iron into a converter for converting and extracting vanadium, and adding porous silicon dioxide in the middle stage of vanadium extraction, wherein the porous silicon dioxide is spherical particles, and the average particle size of the porous silicon dioxide is 0.5-1 mm.

2. The method for extracting vanadium according to claim 1, wherein the porous silica is added in an amount of 0.5 to 2 kg/ton of molten iron.

3. The method for extracting vanadium according to claim 2, wherein the porous silica is added in an amount of 1 to 2 kg/ton of molten iron.

4. The method as claimed in claim 1, wherein the silicon content of the low-silicon vanadium-containing molten iron is less than or equal to 0.20%, and the temperature of the molten iron before the blowing vanadium extraction is 1200-1300 ℃.

5. The vanadium extraction method according to claim 1, further comprising adding lime powder at the early stage of vanadium extraction, wherein the addition amount of the lime powder is 10-30 kg/ton of molten iron.

6. The vanadium extraction method according to claim 5, wherein the lime powder is added in an amount of 10-20 kg/ton molten iron.

7. A vanadium extraction method according to claim 5, characterized in that the portion of the lime powder used, with a particle size in the range of 0.5-1.5mm, accounts for 80-85% of the total mass.

8. The vanadium extraction method according to any one of claims 1 to 7, characterized in that the vanadium extraction method is as follows: blowing oxygen into the converter through an oxygen lance, wherein the blowing oxygen strength is 2.0-2.5Nm³Per min per ton of molten iron.

9. The method for extracting vanadium according to claim 8, wherein the blowing is performed at a low lance position in an early stage, at a high lance position in a middle stage and at a low lance position in a later stage.

10. The method for extracting vanadium according to claim 9, wherein the low lance position blowing is 1300-1400mm at the lance position of the oxygen lance, and the high lance position blowing is 1600-1700mm at the lance position of the oxygen lance.

Technical Field

The invention belongs to the technical field of steel smelting, and particularly relates to a method for extracting vanadium from low-silicon vanadium-containing molten iron.

Background

Vanadium belongs to a precious metal, is an important industrial raw material, and is widely applied to the fields of steel, chemical industry, aerospace, electronic industry, biology, agriculture and the like at present. Vanadium is widely distributed in nature, accounting for about 0.02% of the crust mass, but is very dispersed and often intergrown with other metal ores, so that during mining and processing of these ores, vanadium is recovered as an intergrowth product or by-product. The vanadium-titanium magnetite is a main mineral resource of vanadium, and after vanadium-titanium magnetite is smelted into molten iron in general, vanadium slag is obtained through oxidation blowing, and the vanadium slag is a main raw material for further producing vanadium products.

The forming process of the vanadium slag comprises the following steps: at least part of silicon, vanadium, manganese, titanium and iron in the molten iron is oxidized into stable oxides, the formed vanadium oxide combination is called vanadium slag, and the molten iron after vanadium extraction is called semisteel. Because the specific gravity of the formed vanadium oxide is smaller than that of the semisteel, the semisteel flows into the semisteel tank from the steel tapping hole by using the converter, vanadium slag is remained in the converter, the semisteel is used as a raw material for converter steelmaking in the next process, and the vanadium slag is poured into the slag tank from the furnace tapping hole and used as a raw material for producing vanadium products in the next process.

The vanadium extraction process is an oxidation reaction process of elements such as iron, vanadium, carbon, silicon, manganese, titanium, phosphorus, sulfur and the like in molten iron, and the oxidation reaction of the elements is carried out at a speed which depends on chemical compositions of the molten iron and thermodynamic and kinetic conditions during vanadium blowing. In the oxygen potential diagram, a carbon-oxygen potential line and a vanadium-oxygen potential line have an intersection point, and the corresponding temperature is called carbon-vanadium conversion temperature. Below this temperature, vanadium is preferentially oxidized with respect to carbon, above this temperature, carbon is preferentially oxidized with respect to vanadium. The vanadium extraction is a physical and chemical reaction process for oxidizing vanadium in molten iron into high-price stable vanadium oxide by stirring the vanadium-containing molten iron in a top-blown converter by using a high-speed pure oxygen jet flow by utilizing a selective oxidation principle.

At present, the problems encountered in the field are that the chemical heat of the low-silicon molten iron is relatively reduced, the slagging is difficult, the slag amount is small, the slagging is not beneficial, the heat is insufficient, the dephosphorization effect is poor, and the like. In order to solve the problem in the industry, patent document 201410275802.3 discloses a method for blowing low-silicon vanadium-containing molten iron, which comprises adding low-silicon vanadium-containing molten iron to be blown into a converter for blowing and extracting vanadium, wherein before blowing and extracting vanadium, silica is added into the low-silicon vanadium-containing molten iron, and the silica is added in the form of quartz sand. Although the mode of supplementing silicon dioxide into the low-silicon molten iron can effectively improve the defect of low silicon, the quartz sand has higher density and can sink rapidly after being added. Also, the bulk oxidation period of silicon is in the middle of the converting period, and the patent does not disclose the addition time of the silica sand. If the quartz sand is added in the early stage of blowing to improve the silicon content, dephosphorization of molten iron is not facilitated, so that the phosphorus content in the vanadium slag is too high, and the vanadium slag is prepared and used in the next step.

Therefore, the experience of the present inventors in long-term working practice is that the blowing of low-silicon molten iron must be improved in stages, and it cannot be said that the low silicon content in the molten iron is substantially counterproductive to supplement silicon element. Besides improving the silicon content in the molten iron, the alkalinity of the slag should be controlled, the dephosphorization effect is improved, and the grade of the vanadium slag is improved.

Disclosure of Invention

Based on the defects of the prior art, the invention provides a method for extracting vanadium from low-silicon vanadium-containing molten iron, which divides a blowing vanadium extraction process into an early stage, a middle stage and a later stage, and does not specifically limit specific time nodes of the three stages. Because the blowing vanadium extraction process is divided into a front stage, a middle stage and a rear stage, or a first stage, a second stage and a third stage, which are common time node distribution modes used by a person skilled in the art, the time node distribution modes have no specific time limit, and a person skilled in the operation flow generally judges the blowing stage according to experience so as to change the lance position of the vanadium extraction oxygen lance and other operations. According to the practical operation experience of technicians, the lime powder is added in the early stage of blowing to promote the formation of alkaline oxidation slag, so that the early-stage dephosphorization reaction is more thorough. Porous silicon dioxide is added in the middle stage of blowing, the porous silicon dioxide not only supplements the defect of low silicon content in the low-silicon molten iron, increases the temperature of the molten iron and assists vanadium oxidation, but also has stronger adsorption effect, can gather the formed vanadium slag, increases the fluidity of the vanadium slag, and is convenient for the discharge and use of the subsequent vanadium slag.

The invention aims to provide a method for extracting vanadium from low-silicon vanadium-containing molten iron, which improves the vanadium extraction by blowing to ensure that V in the finally obtained vanadium slag₂O₅Higher content, effectively improves vanadiumThe oxidation rate. In addition, the vanadium extraction method ensures that the dephosphorization of the molten iron is more thorough, and the phosphorus content in the semisteel after vanadium extraction is within 0.014%.

The purpose of the invention is realized by the following technical scheme.

The invention provides a method for extracting vanadium from low-silicon vanadium-containing molten iron, which comprises the steps of adding the molten iron into a converter for converting and extracting vanadium, and adding porous silicon dioxide in the middle stage of vanadium extraction, wherein the porous silicon dioxide is spherical particles, and the average particle size is 0.5-1 mm.

Preferably, the amount of the porous silica added is 0.5-2 kg/ton of molten iron.

More preferably, the porous silica is added in an amount of 1 to 2 kg/ton of molten iron.

The silicon content of the low-silicon vanadium-containing molten iron is less than or equal to 0.20 percent, and the temperature of the molten iron is 1200-1300 ℃ before the vanadium is extracted by blowing.

In a preferred embodiment of the invention, the method for extracting vanadium further comprises adding lime powder at the early stage of vanadium extraction, wherein the adding amount of the lime powder is 10-30 kg/ton of molten iron.

More preferably, the adding amount of the lime powder is 10-20 kg/ton molten iron.

The lime powder used in the invention has a particle size of 0.5-1.5mm, and accounts for 80-85% of the total mass.

In a specific embodiment of the invention, the vanadium extraction method comprises the following steps: blowing oxygen into the converter through an oxygen lance, wherein the blowing oxygen strength is 2.0-2.5Nm³Per min per ton of molten iron.

More preferably, the blowing is performed at a low lance position in the early stage of the blowing, at a high lance position in the middle stage of the blowing, and at a low lance position in the later stage of the blowing.

The low lance position blowing is that the lance position of the oxygen lance is 1300-1400mm, and the high lance position blowing is that the lance position of the oxygen lance is 1600-1700 mm.

In the early stage of converter blowing, because the silicon content in the low-silicon molten iron is low, the temperature rise speed of a molten pool is relatively slow, the temperature of the molten pool is low in the early stage and alkaline oxidation slag is formed, so that the thermodynamic conditions of dephosphorization reaction are just met. At the moment, a proper amount of lime powder is added into the molten iron, so that the forming speed of alkaline oxidation slag is accelerated, the alkalinity of the formed alkaline slag is 3.0-4.0, the dephosphorization is promoted to develop towards the positive direction, and the phosphorus in the molten iron is greatly oxidized in the early stage. The inventors have found that increasing the rate of dephosphorization in the early stage reduces the late re-evolution of phosphorus into the semisteel. Finally, the phosphorus content in the semisteel can be up to 0.014% by the method.

The inventors of the present invention have unexpectedly found that the addition of a suitable amount of porous silica to molten iron in the middle of the converting stage achieves the following advantageous effects: 1, supplementing silicon content in low-silicon molten iron in a proper amount, accelerating the temperature rise of a molten pool, and realizing high oxidation rate of vanadium in the molten pool at a higher temperature; and 2, the porous silicon dioxide has an adsorption function, can adsorb and aggregate vanadium slag, increases the volume of the vanadium slag, increases the fluidity of the vanadium slag and is convenient for discharging the vanadium slag.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example of vanadium extraction from low-silicon vanadium-containing molten iron

Example 1

Adding 130 tons of low-silicon vanadium-containing molten iron into a 200-ton vanadium extraction converter, wherein the silicon content in the molten iron is 0.2 percent, the vanadium content is 0.35 percent, and the temperature of the initial molten iron for extracting vanadium is about 1300 ℃. The blowing adopts a constant-pressure variable-lance operation mode, and the oxygen blowing intensity is 2.5Nm³Controlling the lance position of the vanadium extraction oxygen lance, blowing at the earlier stage at a low lance position, controlling the lance position to be about 1400mm, and blowing time to be 1.5-2.5 min. And (3) adding porous silicon dioxide with the average grain diameter of 0.5-1mm into the converter in the middle period, wherein the adding amount is 0.5 kg/ton of molten iron, blowing at a high lance position, controlling the lance position to be about 1600mm, and the blowing time to be 2.5-3 min. And (3) blowing at a low lance position in the later period, controlling the lance position to be about 1400mm, and blowing for 1-2 min. Separating after the blowing is finished to obtain vanadium slag and semisteel, and checking V in the vanadium slag₂O₅Content, calculating vanadium oxidation rate, detecting phosphorus content in semisteel, and integratingThe results are shown in Table 1.

Since all the experiments of the present invention were carried out in the same vanadium iron plant, the composition of the low-silicon vanadium-containing molten iron in the following examples can be regarded as the same as that in example 1.

Example 2

The operation method is the same as that of example 1, except that the amount of the porous silica added in the middle stage of the blowing is 1 kg/ton of molten iron, the average particle size of the porous silica is the same as that of example 1, vanadium slag and semisteel are obtained after the blowing, and V in the vanadium slag is checked₂O₅And (3) calculating the vanadium oxidation rate, detecting the phosphorus content in the semisteel, and obtaining the statistical result shown in table 1.

Example 3

The operation method is the same as that of example 1, except that the amount of the porous silica added in the middle stage of the blowing is 2 kg/ton of molten iron, the average particle size of the porous silica is the same as that of example 1, vanadium slag and semisteel are obtained after the blowing, and V in the vanadium slag is checked₂O₅And (3) calculating the vanadium oxidation rate, detecting the phosphorus content in the semisteel, and obtaining the statistical result shown in table 1.

Example 4

The operation method is the same as that of example 1, except that lime powder with the particle size of 0.5-1.5mm is added into the converter in the early stage of converting, the adding amount of the lime powder is 10 kg/ton of molten iron, the adding amount of the porous silica in the middle stage of converting is 1 kg/ton of molten iron, and the average particle size of the porous silica is the same as that of example 1. Obtaining vanadium slag and semisteel after the converting is finished, and checking V in the vanadium slag₂O₅And (3) calculating the vanadium oxidation rate, detecting the phosphorus content in the semisteel, and obtaining the statistical result shown in table 1.

Example 5

The operation method is the same as that of example 4, except that the addition amount of the lime powder at the early stage of the blowing is 20 kg/ton of molten iron, vanadium slag and semisteel are obtained after the blowing, and V in the vanadium slag is checked₂O₅And (3) calculating the vanadium oxidation rate, detecting the phosphorus content in the semisteel, and obtaining the statistical result shown in table 1.

Example 6

The operation method is the same as that of example 4, except that the lime powder is added in an early stage of converting at 30 kg/ton molten iron, vanadium slag and semisteel are obtained after converting, and V in the vanadium slag is checked₂O₅And (3) calculating the vanadium oxidation rate, detecting the phosphorus content in the semisteel, and obtaining the statistical result shown in table 1.

Comparative example 1

The operation method is the same as that of example 4, except that the ordinary silicon dioxide is added in the middle stage of the blowing, the addition amount is 5 kg/ton molten iron, vanadium slag and semisteel are obtained after the blowing, and V in the vanadium slag is checked₂O₅And (3) calculating the vanadium oxidation rate, detecting the phosphorus content in the semisteel, and obtaining the statistical result shown in table 1.

TABLE 1 statistics of vanadium extraction efficiency of low-silicon vanadium-containing molten iron

As can be seen from the statistical data in the table, V in the vanadium slag₂O₅The content and the vanadium oxidation rate are in a positive correlation relationship. V in vanadium slag obtained in examples 1 to 6₂O₅The content is more than 20 percent, and V in the obtained vanadium slag is compared with V in the conventional technology (shown as a comparative example 1) in the field₂O₅The content is mostly between 16 and 18%. It is known from the data of examples 1 to 3 that the degree of oxidation of vanadium is related to the amount of porous silica added, and that the effect of the amount of 1 to 2 kg/ton of molten iron is significantly better than that of the amount of 0.5 kg/ton of molten iron. In addition, the technicians observe in the actual production that compared with the comparative example 1 in which the common silicon dioxide is added, the volume of the vanadium slag formed after the porous silicon dioxide is added is obviously increased, the aggregation degree is higher, and the discharge of the vanadium slag is very facilitated.

As can be seen from the statistical results of the phosphorus content in the finally obtained semisteel, the phosphorus content in the semisteel obtained by the vanadium extraction method described in the embodiments 4-6 is within 0.014%, and can reach 0.012% at the lowest. In comparison with examples 4-6, examples 1-3 did not add lime dust in the early stage of the blowing, resulting in a relatively high phosphorus content in the final semisteel. The lime powder is added in the early stage of blowing to contribute to more thorough dephosphorization, wherein the adding amount of the lime powder is 10-20 kg/ton of molten iron.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.