CN115522114B - Method for preparing high-cleanliness medium-high carbon steel liquid in short process - Google Patents

Abstract

The application provides a method for preparing high-cleanliness medium-high carbon steel liquid in a short process, which comprises the following steps: (1) Mixing vanadium-containing iron ore, an additive and a reducing agent, and roasting at 1150-1300 ℃ for 0.5-6 h to obtain vanadium-containing molten iron and titanium-rich slag; (2) Blowing carbon dioxide into the vanadium-containing molten iron in the step (1) to perform deep impurity removal treatment to obtain impurity-removed molten iron and titanium-containing slag; (3) And (3) spraying mixed gas of carbon dioxide and oxygen into the impurity-removed molten iron in the step (2) for decarburization treatment, and stopping spraying when the carbon content in the impurity-removed molten iron is reduced to 0.25-1.70 wt%, so as to obtain the medium-high carbon molten steel. According to the method, high-quality molten steel with sulfur content lower than 30ppm, phosphorus content lower than 50ppm and titanium content lower than 10ppm can be obtained through a two-step impurity removal process and a final decarburization step, so that the preparation of high-cleanliness medium-high carbon steel liquid in a short process is realized, and the method can be used for subsequent smelting of high-quality medium-high carbon steel.

Description

Method for preparing high-cleanliness medium-high carbon steel liquid in short process

Technical Field

The application belongs to the field of ferrous metallurgy, relates to a method for preparing medium-high carbon molten steel, and particularly relates to a method for preparing high-cleanliness medium-high carbon molten steel in a short process.

Background

The steel industry is an important basic industry of national economy, is an important support for building modern strong countries, and is an important field for realizing green low-carbon development. At present, the development of high-end products with high added value and high cleanliness as main attributes is increasingly becoming the main technical field of competition of advanced iron and steel enterprises. Clean steel is a steel grade with very strict control requirements on impurity element content, and the sulfur and phosphorus content is generally not more than 0.01%. When clean steel is smelted, the whole flow of pretreatment, steelmaking, refining and continuous casting is strictly controlled according to the steel grade and the application requirements, and the strict control of the cleanliness of the steel is realized in a high-efficiency and fast-rhythm production organization mode. The high-carbon steel is a high-quality steel with higher carbon content, taking high-carbon chromium bearing steel as an example, the current foreign advanced bearing steel enterprises can control the titanium content to be less than 10ppm, the sulfur content to be less than 20ppm and the phosphorus content to be less than 60ppm, and domestic enterprises still face a small gap.

The iron ore containing vanadium and titanium is a strategic resource which mainly contains iron and is accompanied by various rare high-value metals such as titanium, vanadium and the like, and is a recognized refractory mineral which is typically represented by vanadium-titanium magnetite in Panxi and Decode areas of China. The prior smelting process mainly comprises a traditional blast furnace process and a non-blast furnace process: the process solves the problem of iron utilization in vanadium titanomagnetite, but the produced titanium slag has low grade and cannot be used efficiently, the high content of sulfur and titanium in molten iron leads to heavy steelmaking process tasks and low recovery rate of vanadium element; the non-blast furnace process mainly comprises a direct reduction-electric furnace process, a reduction-grinding and selection process, a sodium treatment vanadium extraction-electric furnace process and the like, and the process processes can realize the effective separation of iron, vanadium and titanium only through two steps and even three steps of high temperature, thereby bringing the defects of long process, large investment, high cost, heavy pollution, low comprehensive utilization degree and the like.

In order to realize the green high-value utilization of the total components of iron, vanadium and titanium in vanadium-titanium-containing ilmenite, the process engineering institute of China academy of sciences developed a method (CN 106854702B) for separating iron, vanadium and titanium in vanadium-titanium-iron concentrate by one-step conversion, which comprises the following steps: (1) Mixing and roasting vanadium-titanium-iron concentrate, an additive and a reducing agent to obtain vanadium-containing pig iron and vanadium-titanium-rich materials; (2) Leaching and filtering the vanadium-rich titanium material in water to obtain vanadium-containing solution and titanium slag. The process constructs a new system for separating low-temperature molten multiphase reaction through sodium reduction coupling, realizes the reduction of iron, sodium modification of vanadium and the melting process of iron and vanadium-rich titanium slag in one step, and produces three products of vanadium-containing pig iron, vanadium-containing solution and titanium slag.

The traditional smelting method of medium-high carbon steel is to add carbon powder into molten steel for carbureting, CN106435084A discloses a smelting method of ultralow-oxygen medium-high carbon steel, and the molten iron is pretreated to ensure that [ S ] of the molten iron is less than or equal to 0.003 percent and is matched with special low-sulfur scrap steel; the end point [ C ] of the converter is controlled to be 0.1-0.2%, the end point [ S ] is less than or equal to 0.01%, carbon powder is adopted for preliminary deoxidation before tapping and during tapping, 50-65% of the total amount of the carbon powder is added before tapping, and 35-50% of the total amount of the carbon powder is added 2-4 min after tapping. Carbon powder is used for carburetion, carbon burning loss is large, the fluctuation of carbon content at the end point is large, and impurities such as titanium, silicon, phosphorus, sulfur and the like are inevitably introduced into auxiliary materials, so that the cleanliness of molten steel is affected. Aiming at the defects of the traditional carburetion method of medium-high carbon steel, CN114657311A discloses an operation method for directly smelting variety steel by duplex semisteel, wherein the duplex semisteel is used for replacing the adding amount of carburant, the medium-high carbon steel is directly blended into molten steel, the used molten iron amount is determined according to the carbon, manganese, phosphorus and sulfur contents of the smelting endpoint of a converter, and only the needed silicon and manganese alloy is added in the deoxidization alloying process. The method is complex in operation, and impurities in semisteel can be introduced into molten steel to influence the quality of the molten steel.

The vanadium extraction semisteel has natural advantages as a molten iron raw material for smelting high-carbon steel. CN113106320a discloses a method for producing medium-high carbon steel 65Mn by using molten iron alloying after vanadium extraction, CN111100977a discloses a method for producing hot rolled high carbon steel, CN102766722a discloses a method for smelting high carbon steel from semisteel; the 3 methods all utilize the traditional steelmaking processes of molten iron desulfurization, converter vanadium extraction, converter smelting, molten iron alloying and LF refining, avoid the loss of other elements such as C content, save steelmaking alloy and reduce production cost. However, the vanadium extraction semisteel is subject to the characteristics of vanadium titano-magnetite, the high sulfur and titanium content of molten iron leads to heavy steelmaking process tasks, the high cleanliness of the molten iron is difficult to ensure, and the recovery rate of vanadium element is low.

Disclosure of Invention

In order to solve the technical problems, the application provides a method for preparing high-purity medium-high carbon steel liquid by a short process of vanadium-containing ilmenite, which is used for preparing high-purity medium-high carbon steel liquid by a short process, and can obtain high-quality molten steel with sulfur content lower than 30ppm, phosphorus content lower than 50ppm and titanium content lower than 10ppm by a final decarburization step through only two steps of impurity removal processes.

In order to achieve the technical effects, the application adopts the following technical scheme:

the application provides a method for preparing high-cleanliness medium-high carbon steel liquid in a short process, which comprises the following steps:

(1) Mixing vanadium-containing iron ore, an additive and a reducing agent, and roasting at 1150-1300 ℃ for 0.5-6 h to obtain vanadium-containing molten iron and titanium-rich slag;

(2) Blowing carbon dioxide into the vanadium-containing molten iron in the step (1) to perform deep impurity removal treatment to obtain impurity-removed molten iron and titanium-containing slag;

(3) And (3) spraying mixed gas of carbon dioxide and oxygen into the impurity-removed molten iron in the step (2) for decarburization treatment, and stopping spraying when the carbon content in the impurity-removed molten iron is reduced to 0.25-1.70 wt%, so as to obtain the medium-high carbon molten steel.

Wherein the temperature of the firing in the step (1) may be 1160 ℃, 1170 ℃, 1180 ℃, 1190 ℃, 1200 ℃, 1210 ℃, 1220 ℃, 1230 ℃, 1240 ℃, 1250 ℃, 1260 ℃, 1270 ℃, 1280 ℃, 1290 ℃, etc., the time of the firing in the step (1) may be 0.6, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, 5.0, 5.25, 5.5, 5.9, etc., and the carbon content in the high-carbon molten steel in the step (3) may be 0.30, 0.35, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.10, 1.20, 1.60, 1.30, 1.60, or the like, but is not limited to the values of these values, but are not limited thereto.

In the application, the sodium modification system has the advantages of extremely strong dephosphorization, sulfur and titanium removal, vanadium-containing molten iron with low phosphorus, sulfur and titanium can be obtained from vanadium-containing ilmenite in one step, the extremely low phosphorus and sulfur content is the main characteristic of the molten iron, and simultaneously the titanium and silicon content in the molten iron is also extremely low and far lower than that of the conventional blast furnace molten iron or the molten iron of other direct reduction processes, so that the traditional pretreatment process of 'three-removal of molten iron' is not needed, and impurities such as sulfur, phosphorus, titanium and silicon can be controlled to extremely low level from the source of molten iron, thereby providing high-purity molten iron base materials for the steelmaking process and reducing the impurity removal burden in the steelmaking process; in order to further improve the purity of the molten iron, CO is selected ₂ Deep impurity removal and decarbonization are carried out, and the blowing endpoint [ O ] can be reduced]Realizes the preparation of high-cleanliness medium-high carbon steel liquid in a short process, and can be used for the subsequent smelting of high-quality medium-high carbon steel.

In the application, the temperature of the sodium reduction roasting in the step (1) is limited to 1150-1300 ℃ and the time is limited to 0.5-6 h, so that the conditions of the sodium reduction roasting are further optimized. The main reason is that proper reduction temperature and time are important factors for ensuring lower content of phosphorus, sulfur, titanium and other impurities in molten iron; when the roasting temperature is too low, slag iron cannot be fully separated, and when the roasting temperature is too high, excessive phosphorus, sulfur and titanium elements can be reduced into molten iron; when the roasting time is insufficient, the slag and iron are separated poorly, and the property of slag is changed due to the overlong roasting time, so that the impurity content in molten iron exceeds the standard, and the difficulty is increased for the subsequent impurity removal process.

In the present application, inIn the smelting process, the sequence of oxidation reaction of various elements in molten iron at a low temperature stage (such as 1300 ℃) is Ti, si, P, V, cr, mn, C; as the temperature increases, the carbon oxidation reaction begins and the sequence in which oxidation reactions occur during the high temperature phase (e.g., 1600 ℃) is C, ti, si, V, cr, mn. Based on the principle, the steps of impurity removal and decarburization can be realized. O (O) ₂ Strong oxidizing property, intense reaction during blowing, molten steel end point [ C ]]The content is not easy to control, and a carburant is required to be added in a later period. CO ₂ The oxidability is weak, the reaction is mild during blowing, carbon is hardly lost in the low-temperature impurity removal stage, and harmful impurities are basically removed; in the high-temperature decarburization stage, the carbon loss is slower, and the endpoint content of carbon is easy to control. Due to CO ₂ +c=2co is an endothermic reaction, resulting in a decrease in the temperature of molten steel, and thus, a certain proportion of O may be mixed in the high temperature decarburization stage ₂ Control of decarburization rate and molten steel temperature was performed.

As a preferred embodiment of the present application, the vanadium-containing iron ore in step (1) includes any one or a combination of at least two of vanadium titano-magnetite, vanadium-titanium iron concentrate, vanadium-containing iron concentrate or vanadium-containing ilmenite, and typical but non-limiting examples of the combination are: a combination of vanadium titano-magnetite and vanadium titano-magnetite concentrate, a combination of vanadium titano-ilmenite concentrate and vanadium-containing iron concentrate, a combination of vanadium-containing iron concentrate and vanadium-containing ilmenite, a combination of vanadium-titano-ilmenite and vanadium titano-magnetite or a combination of vanadium titano-magnetite, vanadium-titano-ilmenite concentrate and vanadium-containing iron concentrate, etc.

Preferably, the additive of step (1) comprises any one or a combination of at least two of sodium hydroxide, sodium carbonate or sodium bicarbonate, typical but non-limiting examples of which are: a combination of sodium hydroxide and sodium carbonate, a combination of sodium carbonate and sodium bicarbonate, a combination of sodium bicarbonate and sodium hydroxide, or a combination of sodium hydroxide, sodium carbonate and sodium bicarbonate, or the like.

Preferably, the reducing agent of step (1) comprises any one or a combination of at least two of coal, coke or graphite, typical but non-limiting examples of which are: a combination of coal and coke, a combination of coke and graphite, a combination of graphite and coal, or a combination of coal, coke and graphite, etc.

As a preferred technical scheme of the application, the mass ratio of the vanadium-containing iron ore to the additive in the step (1) is 100 (50-100), such as 100:55, 100:60, 100:65, 100:70, 100:75, 100:80, 100:85, 100:90 or 100:95, etc., but the application is not limited to the listed arrangement, and other non-listed values in the numerical range are equally applicable.

Preferably, the mass ratio of the iron ore containing vanadium to the reducing agent in the step (1) is 100 (25-40), such as 100:26, 100:27, 100:28, 100:29, 100:30, 100:31, 100:32, 100:33, 100:34, 100:35, 100:36, 100:37, 100:38 or 100:39, etc., but not limited to the listed settings, and other non-listed values within the range of values are equally applicable.

As a preferable technical scheme of the application, in the vanadium-containing molten iron in the step (1), the mass percent of iron is 90% -96%, the mass percent of carbon is 3% -5%, the mass percent of vanadium is 0.05% -1.5%, the mass percent of titanium is 0.03% -0.001%, the mass percent of phosphorus is 0.005% -0.0002%, and the mass percent of sulfur is 0.003% -0.0002%.

The iron content may be 91%, 92%, 93%, 94%, 95%, etc., the carbon content may be 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, etc., the titanium content may be 0.002%, 0.005%, 0.01%, 0.015%, 0.02%, 0.025%, 0.029%, etc., the phosphorus content may be 0.0005%, 0.001%, 0.0015%, 0.002%, 0.0025%, 0.003%, 0.0035%, 0.004%, 0.0045%, etc., and the sulfur content may be 0.0005%, 0.001%, 0.0015%, 0.002%, or 0.0025%, etc., but the present application is not limited to the above-mentioned ranges, and other non-exemplified values may be applied.

In a preferred embodiment of the present application, the temperature of the deep impurity removal treatment in the step (2) is 1200 to 1450 ℃, such as 1220 ℃, 1250 ℃, 1280 ℃,1300 ℃, 1320 ℃, 1350 ℃, 1380 ℃, 1400 ℃, 1430 ℃, etc., but the present application is not limited to the above-mentioned configuration, and other values not shown in the above-mentioned numerical range are equally applicable.

Preferably, the time of the deep impurity removal treatment in the step (2) is 5-20 min, such as 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min or 19min, but not limited to the listed settings, and other non-listed values in the numerical range are equally applicable.

As a preferable technical scheme of the application, the flow rate of the carbon dioxide sprayed in the step (2) is 0.5-5 Nm ³ /t _{Molten iron} Min, e.g. 1Nm ³ /t _{Molten iron} ·min、1.5Nm ³ /t _{Molten iron} ·min、2Nm ³ /t _{Molten iron} ·min、2.5Nm ³ /t _{Molten iron} ·min、3Nm ³ /t _{Molten iron} ·min、3.5Nm ³ /t _{Molten iron} ·min、4Nm ³ /t _{Molten iron} Min or 4.5Nm ³ /t _{Molten iron} Min, etc., but is not limited to the listed settings, and other non-listed values within this range are equally applicable.

In the present application, the CO of step (2) ₂ The gas can be pure CO ₂ Gas, or use of CO ₂ The gas volume ratio is not less than 50%, and the rest components are Ar or N ₂ A mixed gas of inert gases; the CO ₂ The gas feed gas is executed by referring to the standard of GB/T6052-2011 industrial liquid carbon dioxide, and sulfides and phosphides cannot exceed the standard; the blowing mode adopts modes such as top blowing, bottom blowing, side blowing or top and bottom combined blowing.

In a preferred embodiment of the present application, the decarburization treatment in the step (3) is carried out at a temperature of 1500 to 1700 ℃, such as 1520 ℃, 1550 ℃, 1580 ℃,1600 ℃, 1620 ℃, 1650 ℃ or 1680 ℃, etc., but the decarburization treatment is not limited to the above-mentioned examples, and other values not shown in the above-mentioned numerical range are equally applicable.

As a preferable technical scheme of the application, the flow rate of the mixed gas of the carbon dioxide and the oxygen sprayed in the step (3) is 0.5-5 Nm ³ /t _{Molten iron} Min, e.g. 1Nm ³ /t _{Molten iron} ·min、1.5Nm ³ /t _{Molten iron} ·min、2Nm ³ /t _{Molten iron} ·min、2.5Nm ³ /t _{Molten iron} ·min、3Nm ³ /t _{Molten iron} ·min、3.5Nm ³ /t _{Molten iron} ·min、4Nm ³ /t _{Molten iron} Min or 4.5Nm ³ /t _{Molten iron} Min, etc., but is not limited to the listed settings, and other non-listed values within this range are equally applicable.

In the application, the spraying in the step (3) can adopt CO ₂ With O ₂ Mixed gas with arbitrary proportion or CO ₂ With O ₂ The volume fraction of the mixed gas with any proportion is not less than 50%, and the rest components are Ar or N ₂ A mixed gas of inert gases; the CO ₂ The gas feed gas is executed by referring to the standard of GB/T6052-2011 industrial liquid carbon dioxide, and sulfides and phosphides cannot exceed the standard; the blowing mode adopts modes such as top blowing, bottom blowing, side blowing or top and bottom combined blowing.

As a preferable technical scheme of the application, in the medium-high carbon molten steel in the step (3), the mass percent of carbon is 0.25-1.70%, the mass percent of titanium is 0.001-0.00001%, the mass percent of phosphorus is 0.005-0.0002%, the mass percent of sulfur is 0.003-0.0002%, and the balance is iron, conventional elements and other residual elements.

The percentage by mass of carbon may be 0.30%, 0.35%, 0.40%, 0.50%, 0.60%, 0.70%, 0.80%, 0.90%, 1.00%, 1.10%, 1.20%, 1.30%, 1.40%, 1.50% or 1.60%, etc., the percentage by mass of titanium may be 0.00005%, 0.0001%, 0.0002%, 0.0005%, 0.0008% or 0.001%, etc., the percentage by mass of phosphorus may be 0.0005%, 0.001%, 0.0015%, 0.002%, 0.0025%, 0.003%, 0.0035%, 0.004% or 0.0045%, etc., and the percentage by mass of sulfur may be 0.0005%, 0.001%, 0.0015%, 0.002% or 0.0025%, etc., but the percentage by mass of sulfur is not limited to the above-mentioned values, and other non-exemplified values within the respective ranges are equally applicable.

As a preferable technical scheme of the application, the method for preparing the high-cleanliness medium-high carbon steel liquid by the short process comprises the following steps:

(1) Mixing vanadium-containing iron ore, an additive and a reducing agent according to the mass ratio of 100 (50-100) (25-40), and roasting at 1150-1300 ℃ for 0.5-6 h to obtain vanadium-containing molten iron and titanium-rich slag;

(2) Blowing carbon dioxide into the vanadium-containing molten iron in the step (1) at the temperature of 1200-1450 ℃ for deep impurity removal treatment for 5-20 min, wherein the flow rate of the blowing carbon dioxide is 0.5-5 Nm ³ /t _{Molten iron} Min, obtaining impurity-removed molten iron and titanium-containing slag;

(3) Blowing mixed gas of carbon dioxide and oxygen into the impurity-removed molten iron in the step (2) at 1500-1700 ℃ for decarburization treatment, wherein the flow rate of the mixed gas of the carbon dioxide and the oxygen is 0.5-5 Nm ³ /t _{Molten iron} And (2) min, stopping blowing when the carbon content in the impurity-removed molten iron is reduced to 0.25-1.70%, and obtaining the medium-high carbon molten steel.

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

the application provides a method for preparing high-purity medium-high carbon steel liquid by a short process, which is characterized in that high-quality molten steel with sulfur content lower than 30ppm, phosphorus content lower than 50ppm and titanium content lower than 10ppm can be obtained by a two-step impurity removal process and a final decarburization step, so that the preparation of the high-purity medium-high carbon steel liquid by the short process is realized, and the method can be used for subsequent smelting of high-quality medium-high carbon steel.

Detailed Description

To facilitate understanding of the present application, examples are set forth below. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the application and are not to be construed as a specific limitation thereof.

Example 1

The embodiment provides a method for preparing high-cleanliness medium-high carbon steel liquid in a short process, which comprises the following steps:

(1) Mixing vanadium titano-magnetite, sodium hydroxide and coke according to a mass ratio of 100:60:25, and roasting at 1150 ℃ for 2.5 hours to obtain vanadium-containing molten iron and titanium-rich slag;

the vanadium-containing molten iron comprises 94.26% of iron, 3.6% of carbon, 0.0172% of titanium, 0.0014% of phosphorus and 0.0002% of sulfur by mass;

(2) Injecting pure carbon dioxide into the vanadium-containing molten iron in the step (1) at 1200 ℃ for deep impurity removal treatment for 20min, wherein the flow rate of the injected carbon dioxide is 0.5Nm ³ /t _{Molten iron} Min, separating gold slag to obtain impurity-removed molten iron and titanium-containing slag;

(3) Blowing mixed gas of carbon dioxide and oxygen (volume ratio of 1:1) to the impurity-removed molten iron in the step (2) at 1500 ℃ for decarburization treatment, wherein the flow rate of the mixed gas of the carbon dioxide and the oxygen is 0.5Nm ³ /t _{Molten iron} Min, stopping blowing when the carbon content in the impurity-removed molten iron is reduced to 1.70%, and separating gold slag to obtain the medium-high carbon molten steel;

the mass percentage of carbon in the medium-high carbon molten steel is 1.70%, the mass percentage of titanium is 0.0007%, the mass percentage of phosphorus is 0.0028%, the mass percentage of sulfur is 0.0005%, and the balance is iron, conventional elements and other residual elements.

Example 2

The embodiment provides a method for preparing high-cleanliness medium-high carbon steel liquid in a short process, which comprises the following steps:

(1) Mixing vanadium titano-magnetite, sodium bicarbonate and graphite according to a mass ratio of 100:100:40, and roasting at 1300 ℃ for 0.75h to obtain vanadium-containing molten iron and titanium-rich slag;

the vanadium-containing molten iron comprises, by mass, 95.33% of iron, 3.2% of carbon, 0.0126% of titanium, 0.0034% of phosphorus and 0.0017% of sulfur;

(2) Spraying pure carbon dioxide to the vanadium-containing molten iron in the step (1) at 1400 ℃ for deep impurity removal treatment for 5min, wherein the flow rate of the sprayed carbon dioxide is 5Nm ³ /t _{Molten iron} Min, separating gold slag to obtain impurity-removed molten iron and titanium-containing slag;

(3) Spraying mixed gas of carbon dioxide and oxygen (volume ratio of 1:1) to the impurity-removed molten iron in the step (2) at 1700 ℃ for decarburization treatment, wherein the flow rate of the mixed gas sprayed with the carbon dioxide and the oxygen is 5Nm ³ /t _{Molten iron} Min, when the impurity removing molten ironStopping blowing when the carbon content is reduced to 0.25%, and separating the gold slag to obtain the medium-high carbon molten steel;

the mass percent of carbon in the medium-high carbon molten steel is 0.25%, the mass percent of titanium is 0.0004%, the mass percent of phosphorus is 0.00036%, the mass percent of sulfur is 0.0021%, and the balance is iron, conventional elements and other residual elements.

Example 3

The embodiment provides a method for preparing high-cleanliness medium-high carbon steel liquid in a short process, which comprises the following steps:

(1) Mixing vanadium titano-magnetite, sodium carbonate and coke according to a mass ratio of 100:80:30, and roasting at 1200 ℃ for 2 hours to obtain vanadium-containing molten iron and titanium-rich slag;

the vanadium-containing molten iron comprises 96.44% of iron by mass, 3.5% of carbon by mass, 0.0019% of titanium by mass, 0.0008% of phosphorus by mass and 0.0003% of sulfur by mass;

(2) Injecting pure carbon dioxide into the vanadium-containing molten iron in the step (1) at 1350 ℃ for deep impurity removal treatment for 12min, wherein the flow rate of the injected carbon dioxide is 2Nm ³ /t _{Molten iron} Min, separating gold slag to obtain impurity-removed molten iron and titanium-containing slag;

(3) Blowing mixed gas of carbon dioxide and oxygen (volume ratio is 1:1) into the impurity-removed molten iron in the step (2) at 1600 ℃ for decarburization treatment, wherein the flow rate of the mixed gas of the carbon dioxide and the oxygen is 2Nm ³ /t _{Molten iron} Min, stopping blowing when the carbon content in the impurity-removed molten iron is reduced to 0.5%, and separating gold slag to obtain the vanadium-containing medium-high carbon molten steel;

the mass percentage of carbon in the medium-high carbon molten steel is 0.5%, the mass percentage of titanium is 0.0001%, the mass percentage of phosphorus is 0.0011%, the mass percentage of sulfur is 0.0006%, and the balance is iron, conventional elements and other residual elements.

Example 4

This example was conducted in the same manner as in example 3 except that the baking temperature in step (1) was 1250℃and the baking time was 5 hours.

The mass percent of carbon in the medium-high carbon molten steel is 0.5%, the mass percent of titanium is 0.0002%, the mass percent of phosphorus is 0.0012%, the mass percent of sulfur is 0.0009%, and the balance is iron, conventional elements and other residual elements.

Comparative example 1

The comparative example was conducted in the same manner as in example 3 except that the firing temperature in the step (1) was 1400 ℃.

The mass percent of carbon in the medium-high carbon molten steel is 0.5%, the mass percent of titanium is 0.0003%, the mass percent of phosphorus is 0.0076%, the mass percent of sulfur is 0.0024%, and the balance is iron, conventional elements and other residual elements.

Comparative example 2

The comparative example was conducted in the same manner as in example 3 except that the baking time in the step (1) was 10 hours.

The mass percent of carbon in the vanadium-containing medium-high carbon molten steel is 0.5%, the mass percent of titanium is 0.0007%, the mass percent of phosphorus is 0.0103%, the mass percent of sulfur is 0.0037%, and the balance is iron, conventional elements and other residual elements.

Comparative example 3

This comparative example was conducted in the same manner as in example 3 except that the impurity removal temperature in the step (2) was 1500 ℃.

The mass percent of carbon in the medium-high carbon molten steel is 0.5%, the mass percent of titanium is 0.0016%, the mass percent of phosphorus is 0.0013%, the mass percent of sulfur is 0.0010%, and the balance is iron, conventional elements and other residual elements.

The applicant states that the detailed process equipment and process flows of the present application are described by the above examples, but the present application is not limited to, i.e., does not mean that the present application must be practiced in dependence upon, the above detailed process equipment and process flows. It should be apparent to those skilled in the art that any modification of the present application, equivalent substitution of raw materials for the product of the present application, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present application and the scope of disclosure.

Claims (12)

1. A method for preparing high-purity medium-high carbon steel liquid in a short process, which is characterized by comprising the following steps:

(1) Mixing vanadium-containing iron ore, an additive and a reducing agent, and roasting at 1150-1300 ℃ for 0.5-6 h to obtain vanadium-containing molten iron and titanium-rich slag;

(2) Blowing carbon dioxide into the vanadium-containing molten iron in the step (1) to carry out deep impurity removal treatment, wherein the temperature of the deep impurity removal treatment is 1200-1450 ℃, so as to obtain impurity-removed molten iron and titanium-containing slag;

(3) And (3) spraying mixed gas of carbon dioxide and oxygen into the impurity-removed molten iron in the step (2) to carry out decarburization treatment, wherein the temperature of the decarburization treatment is 1500-1700 ℃, and when the carbon content in the impurity-removed molten iron is reduced to 0.25-1.70 wt%, the spraying is stopped, so that the medium-high carbon molten steel is obtained.

2. The method of claim 1, wherein the vanadium-containing iron ore of step (1) comprises any one or a combination of at least two of vanadium titano-magnetite, vanadium-containing iron concentrate or vanadium-containing ilmenite.

3. The method of claim 1, wherein the additive of step (1) comprises any one or a combination of at least two of sodium hydroxide, sodium carbonate, or sodium bicarbonate.

4. The method of claim 1, wherein the reducing agent of step (1) comprises any one or a combination of at least two of coal, coke, or graphite.

5. The method according to claim 1, wherein the mass ratio of the vanadium-containing iron ore to the additive in the step (1) is 100 (50-100).

6. The method according to claim 1, wherein the mass ratio of the vanadium-containing iron ore to the reducing agent in the step (1) is 100 (25-40).

7. The method of claim 1, wherein the vanadium-containing molten iron in step (1) comprises 90-96% by mass of iron, 3-5% by mass of carbon, 0.05-1.5% by mass of vanadium, 0.001-0.03% by mass of titanium, 0.0002-0.005% by mass of phosphorus and 0.0002-0.003% by mass of sulfur.

8. The method of claim 1, wherein the depth of the depuration treatment of step (2) is 5 to 20 minutes.

9. The method according to claim 1, wherein the flow rate of the injected carbon dioxide in the step (2) is 0.5-5 Nm ³ /t _{Molten iron} ·min。

10. The method according to claim 1, wherein the flow rate of the mixed gas of carbon dioxide and oxygen blown in the step (3) is 0.5 to 5Nm ³ /t _{Molten iron} ·min。

11. The method of claim 1, wherein the medium and high carbon molten steel in step (3) comprises 0.25 to 1.70 mass percent of carbon, 0.00001 to 0.001 mass percent of titanium, 0.0002 to 0.005 mass percent of phosphorus, 0.0002 to 0.003 mass percent of sulfur, and the balance of iron and conventional elements and other residual elements.

12. The method according to any one of claims 1-11, characterized in that the method comprises the steps of:

(1) Mixing vanadium-containing iron ore, an additive and a reducing agent according to the mass ratio of 100 (50-100) (25-40), and roasting at 1150-1300 ℃ for 0.5-6 h to obtain vanadium-containing molten iron and titanium-rich slag;

(2) Blowing carbon dioxide into the vanadium-containing molten iron in the step (1) at the temperature of 1200-1450 ℃ to remove impurities deeplyThe flow rate of the injected carbon dioxide is 0.5-5 Nm after 5-20 min ³ /t _{Molten iron} Min, obtaining impurity-removed molten iron and titanium-containing slag;

(3) Blowing mixed gas of carbon dioxide and oxygen into the impurity-removed molten iron in the step (2) at 1500-1700 ℃ for decarburization treatment, wherein the flow rate of the mixed gas of the carbon dioxide and the oxygen is 0.5-5 Nm ³ /t _{Molten iron} And (2) min, stopping blowing when the carbon content in the impurity-removed molten iron is reduced to 0.25-1.70%, and obtaining the medium-high carbon molten steel.