Extremely-low-sulfur industrial pure iron RH demanganizing agent as well as preparation method and use method thereof

Abstract

The invention relates to an extremely-low-sulfur industrial pure iron RH demanganizing agent as well as a preparation method and a use method thereof, and belongs to the technical field of steelmaking. The invention provides an extremely-low-sulfur industrial pure iron RH demanganizing agent which comprises the following raw materials in parts by weight: 6-7 parts of hot-rolled iron oxide scale, 1-2 parts of lime and 1-2 parts of silica. In the RH treatment process, after the demanganizing agent enters molten steel, Mn in the molten steel is oxidized on the surface of the oxidizing demanganizing agent by controlling the components of slag entering a station and molten steel entering the station and the process in the RH treatment process, generated MnO forms CaO-SiO2-(MnO-FeO) system slag under the action of CaO and SiO2 contained in the demanganizing agent, the slag system is low in melting point, and the slag system is low in melting point and high in demanganizing efficiency. MnO in the steel slag can be controlled to be reduced into molten steel, so that the demanganization rate of extremely-low-sulfur industrial pure iron RH refining is increased.

Description

Technical Field

[0001] The present application relates to the technical field of steelmaking, and in particular to an extremely low-sulfur industrial pure iron RH demanganeseizing agent and a preparation method and a use method thereof. Background Art

[0002] Industrial pure iron, as an iron alloy with very low carbon content, is mainly used for smelting various high-temperature alloys, heat-resistant alloys, precision alloys and other aerospace, military and other materials. When the S content of industrial pure iron increases, the ability of pure iron to resist hydrogen-induced cracking and sulfur stress cracking decreases, which in turn affects the forgeability of the material; when the Mn content in industrial pure iron increases, the material's electrical conductivity, temperature coefficient of resistance, saturation magnetic induction, etc. will drop sharply, which in turn affects the material's magnetic conductivity. In summary, for high-end industrial pure iron, the sulfur content of the product usually needs to be controlled within 0.002%, and the manganese content usually needs to be controlled within 0.025%, or even lower.

[0003] In actual production, industrial pure iron is mainly smelted in electric arc furnaces and converters, and needs to be combined with refining processes to improve the purity of molten steel. For ultra-low sulfur industrial pure iron, the refining process usually adopts LF refining + RH refining, that is, desulfurization operations are performed in both LF refining and RH refining processes; according to desulfurization thermodynamics, a low oxidizing environment is a prerequisite for the desulfurization reaction to proceed. This background runs counter to the demanganization reaction that requires high oxidizing conditions. In other words, during the refining process of ultra-low sulfur industrial pure iron, MnO in the slag will be continuously reduced and enter the molten steel, resulting in the difficulty in controlling the Mn element content in the molten steel. At present, when using a converter to produce such high-end industrial pure iron, in order to control the Mn content of the product, double slag operation is usually used in the converter to reduce the manganese content of the molten steel at the converter end point. This not only prolongs the converter cycle and increases the production scheduling pressure, but also makes it difficult to control the double slag at all times, increasing the difficulty of end point control. In addition, with the occurrence of manganese return in the entire refining process, the manganese content of the product often exceeds the control range.

[0004] In this context, the control of manganese content in the refining process of ultra-low sulfur industrial pure iron has become a technical difficulty, seriously affecting the improvement of industrial pure iron quality and production efficiency. Summary of the invention

[0005] The present application provides an ultra-low sulfur industrial pure iron RH demanganese agent and a preparation method and a use method thereof, in order to solve the following technical problem: how to improve the demanganese rate of ultra-low sulfur industrial pure iron RH refining.

[0006] In a first aspect, the present application provides an ultra-low sulfur industrial pure iron RH demanganese agent, wherein the raw materials of the demanganese agent include, by weight: 6 to 7 parts of hot-rolled iron oxide scale, 1 to 2 parts of lime and 1 to 2 parts of silica.

[0007] Optionally, the demanganese agent is spherical, and the diameter of the demanganese agent is 30 mm to 60 mm.

[0008] Optionally, the particle size of the hot-rolled iron oxide scale is 50 mesh to 100 mesh, the particle size of the lime is 100 mesh to 200 mesh, and the particle size of the silica is 100 mesh to 200 mesh.

[0009] Optionally, in terms of mass fraction, the CaO content of the lime is ≥80%, and the SiO2 content of the silica is ≥85%.

[0010] In a second aspect, the present application provides a method for preparing the demanganeseizing agent described in the first aspect, the method comprising: mixing the hot-rolled iron oxide scale, the lime and the silica according to the parts by weight, and pressing them into a sphere.

[0011] In a third aspect, the present application provides a method for using the demanganeseizing agent described in the first aspect, the method comprising:

[0012] Control the chemical composition of the RH incoming slag and the RH incoming molten steel to obtain the initial Mn mass fraction of the RH incoming molten steel;

[0013] According to the mass fraction of the initial Mn, the dosage of the demanganizing agent is obtained;

[0014] In the RH oxygen blowing process, the demanganese agent is put into the vacuum chamber at one time according to the dosage, and the RH incoming molten steel is demanganese treated to obtain demanganese molten steel.

[0015] Optionally, the basicity of the RH incoming slag is R≥5.5.

[0016] Optionally, the CaO mass percentage of the RH incoming slag is 40% to 45%.

[0017] Optionally, the mass percentage of MnO in the RH incoming slag is ≤1.0%.

[0018] Optionally, the TFe mass fraction of the RH incoming slag is ≤20%.

[0019] Optionally, the S mass fraction of the RH incoming molten steel is ≤0.002%.

[0020] Optionally, the O mass fraction of the RH incoming molten steel is ≤0.0005%.

[0021] Optionally, the inlet temperature of the RH inlet molten steel is 1600°C to 1630°C.

[0022] Optionally, the amount of the demanganizing agent obtained according to the mass fraction of the initial Mn comprises:

[0023] If the mass fraction of the initial Mn is ≤0.02%, the amount of the demanganizing agent is 0.4 kg / t steel;

[0024] If the mass fraction of the initial Mn is 0.02% to 0.025%, the amount of the demanganizing agent is 0.7 kg / t steel;

[0025] If the mass fraction of the initial Mn is 0.025% to 0.03%, the dosage of the demanganizing agent is 1.0 kg / t steel.

[0026] Optionally, when the demanganese agent is introduced into the vacuum chamber at one time, the introduction position of the demanganese agent is the upper part of the riser of the vacuum chamber.

[0027] Optionally, the lifting gas of the vacuum chamber is argon, and the argon flow rate is 1400NL / min to 1600NL / min.

[0028] Optionally, the oxygen supply flow rate of the vacuum chamber is 2300m 3 / h~2500m 3 / h, the oxygen supply of the vacuum chamber is 0m 3 ~400m 3 The oxygen lance position of the vacuum chamber is 5.3m to 5.6m.

[0029] Optionally, the ultimate vacuum degree of the vacuum chamber is 0Pa to 67Pa.

[0030] Optionally, the C content of the demanganese molten steel is ≤0.002%.

[0031] Optionally, the temperature of the demanganese molten steel is 1570°C to 1590°C.

[0032] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0033] The present application provides an ultra-low sulfur industrial pure iron RH demanganizing agent, wherein the raw materials of the demanganizing agent include, by weight, 6 to 7 parts of hot rolling scale, 1 to 2 parts of lime, and 1 to 2 parts of silica. During the RH treatment process, by controlling the composition of the incoming slag and the incoming molten steel, as well as the process during the RH treatment process, after the demanganizing agent enters the molten steel, the Mn in the molten steel is oxidized on the surface of the oxidizing demanganizing agent, and the generated MnO forms a CaO-SiO2-(MnO-FeO) system slag under the action of CaO and SiO2 contained in the demanganizing agent. This type of slag has a low melting point, which helps to control the reduction of MnO in the slag into the molten steel, thereby improving the demanganizing rate of the ultra-low sulfur industrial pure iron RH refining. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0036] Figure 1 A schematic flow chart of a method for using an ultra-low sulfur industrial pure iron RH demanganeseizing agent according to some embodiments of the present application; DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0038] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0039] In this document, the terms including "including" and "including" mean "including but not limited to". Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, and "plurality" means two or more; "at least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0040] In a first aspect, the present application provides an ultra-low sulfur industrial pure iron RH demanganese agent, wherein the raw materials of the demanganese agent include, by weight: 6 to 7 parts of hot-rolled iron oxide scale, 1 to 2 parts of lime and 1 to 2 parts of silica.

[0041] The positive effect of controlling the hot rolling scale to 6-7 parts, the lime to 1-2 parts and the silica to 1-2 parts is that this ratio can form a local high oxidizing environment during the RH refining process, which is conducive to the occurrence of the demanganese reaction.

[0042] In some embodiments, the demanganese agent is spherical, and the diameter of the demanganese agent is 30 mm to 60 mm.

[0043] The positive effect of controlling the diameter of the demanganese agent to be 30 mm to 60 mm is that it not only helps the transportation of materials, but also helps the feeding system to add materials. For example, the diameter of the demanganese agent is 30 mm, 35 mm, 40 mm, 50 mm, 60 mm, etc.

[0044] In some embodiments, the particle size of the hot-rolled iron oxide scale is 50-100 mesh, the particle size of the lime is 100-200 mesh, and the particle size of the silica is 100-200 mesh.

[0045] The particle size of hot-rolled iron oxide is 50-100 mesh. Positive effect: Hot-rolled iron oxide is produced in the steel production process. Hot-rolled iron oxide with a particle size of 50-100 mesh has a larger specific surface area than coarser particles. This means that under the same mass, fine particles of iron oxide can have more sufficient contact with the manganese element in the molten iron, thereby improving the efficiency of the demanganese reaction. Exemplarily, the particle size of the hot-rolled iron oxide is 50 mesh, 60 mesh, 70 mesh, 80 mesh, 100 mesh, etc.

[0046] In some embodiments, the CaO content of the lime is ≥ 80%, and the SiO2 content of the silica is ≥ 85%, calculated by mass fraction.

[0047] The positive effect of lime CaO content ≥ 80%: When the CaO content in lime reaches or exceeds 80%, its purity is high, with more effective ingredients, and it can participate more directly in the demanganese reaction, thereby improving the demanganese efficiency. In addition, lime is an important slag-making material in the demanganese process, and its high CaO content helps to form slag with moderate alkalinity and good fluidity, thereby improving the environmental conditions of the demanganese reaction. For example, the CaO content of lime is 80%, 82%, 85%, 89%, 90%, etc.

[0048] Positive effect of silica with SiO2 content ≥ 85%: Silica with SiO2 content ≥ 85% means that its impurity content is relatively low, which helps to reduce unnecessary chemical reactions and the generation of by-products during the manganese removal process, thereby improving the purity and efficiency of the manganese removal agent. Exemplary, the SiO2 content of silica is 85%, 88%, 89%, 90%, 92%, etc.

[0049] In a second aspect, the present application provides a method for preparing the demanganeseizing agent described in the first aspect, the method comprising:

[0050] The hot rolled iron scale, the lime and the silica are mixed according to the weight parts and pressed into a ball shape.

[0051] Figure 1 The present invention is a flow chart of a method for using an ultra-low sulfur industrial pure iron RH demanganeseizing agent according to some embodiments of the present application.

[0052] See also Figure 1 In a third aspect, the present application provides a method for using an extremely low-sulfur industrial pure iron RH demanganeseizing agent, comprising:

[0053] S1. Control the composition of the RH incoming slag and the RH incoming molten steel to obtain the initial Mn mass fraction of the RH incoming molten steel;

[0054] In some embodiments, the basicity R of the RH incoming slag is ≥5.5.

[0055] In an alkaline environment, manganese oxides are relatively stable and are not easily reduced back into molten steel, which is conducive to maintaining a low manganese content. In addition, high-basicity slag has a better ability to absorb inclusions, can effectively absorb non-metallic inclusions in molten steel, reduce the inclusion content in steel, and improve the purity of molten steel. Exemplarily, the basicity of the RH incoming slag is 5.5, 5.7, 6, 6.5, etc.

[0056] In some embodiments, the CaO mass percentage of the RH incoming slag is 40% to 45%.

[0057] The positive effect of controlling the CaO mass percentage of the RH incoming slag to be 40% to 45% is as follows: CaO is one of the main components of desulfurization in the slag. It can combine with the sulfur in the molten steel to form sulfide precipitation in the slag, thereby effectively removing the sulfur element in the molten steel. Within this mass percentage range, the desulfurization capacity of the slag is significantly enhanced, which helps to produce molten steel with a low sulfur content. In addition, CaO, as an alkaline oxide, can form a low-melting-point CaO-SiO2-(MnO-FeO) system slag after combining with MnO and SiO2, which helps to control the reduction of MnO in the slag into the molten steel. Exemplarily, the CaO mass percentage of the RH incoming slag is 40%, 41%, 42%, 43%, 44%, 45%, etc.

[0058] In some embodiments, the mass percentage of MnO in the RH incoming slag is ≤1.0%.

[0059] The positive effect of controlling the MnO mass percentage of the RH incoming slag to ≤1.0% is: if the MnO content in the slag is high, it is possible to enter the molten steel in some way (such as dissolution, diffusion, etc.), increasing the manganese content in the molten steel. By controlling the MnO mass percentage in the slag to ≤1.0%, the possibility of MnO entering the molten steel can be significantly reduced, thereby helping to achieve the goal of manganese removal. Exemplarily, the MnO mass percentage of the RH incoming slag is 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, etc.

[0060] In some embodiments, the TFe mass fraction of the RH incoming slag is ≤20%.

[0061] TFe usually refers to the content of total iron, which mainly exists in the form of FeO. During the RH treatment process, a lower FeO content can reduce the reverse oxidation reaction of manganese, that is, reduce the possibility of the removed manganese being oxidized again and entering the molten steel. Exemplarily, the TFe mass fraction of the RH incoming slag is 5%, 10%, 15%, 18%, 20%, etc.

[0062] In some embodiments, the S mass fraction of the RH incoming molten steel is ≤0.002%.

[0063] The positive effect of controlling the S mass fraction of the RH incoming molten steel to ≤ 0.002% is that the low sulfur content can significantly reduce the formation of sulfide inclusions in the steel, which will reduce the mechanical properties and toughness of the steel.

[0064] In some embodiments, the O mass fraction of the RH incoming molten steel is ≤0.0005%.

[0065] The positive effect of controlling the O mass fraction of the RH incoming steel to ≤ 0.0005% is: low oxygen content means fewer oxide inclusions in the steel, which have an adverse effect on the mechanical properties and processing properties of the steel. By controlling the oxygen content at an extremely low level, the purity and quality of the steel can be significantly improved.

[0066] In some embodiments, the inlet temperature of the RH inlet molten steel is 1600°C to 1630°C.

[0067] The positive effect of controlling the inlet temperature of the RH inlet molten steel to 1600℃~1630℃: within this temperature range, the reaction rate between the manganese element in the molten steel and the demanganizing agent is high. Higher temperatures help increase the activity and collision frequency of the reactants, thereby promoting the demanganizing reaction. In addition, under high temperature conditions, inclusions in the molten steel are more likely to aggregate and float to the surface of the molten steel, thereby being removed, which helps to improve the purity of the molten steel. Exemplarily, the inlet temperature of the RH inlet molten steel is 1600℃, 1610℃, 1620℃, 1630℃, etc.

[0068] S2. According to the mass fraction of the initial Mn, the amount of the demanganizing agent is obtained;

[0069] In some embodiments, obtaining the amount of the demanganizing agent according to the mass fraction of the initial Mn comprises:

[0070] If the mass fraction of the initial Mn is ≤0.02%, the amount of the demanganizing agent is 0.4 kg / t steel;

[0071] If the mass fraction of the initial Mn is 0.02% to 0.025%, the amount of the demanganizing agent is 0.7 kg / t steel;

[0072] If the mass fraction of the initial Mn is 0.025% to 0.03%, the dosage of the demanganizing agent is 1.0 kg / t steel.

[0073] Adding different amounts of demanganese agent to molten steel with different initial manganese contents can ensure that the oxidizability of the molten pool is not excessively affected while playing a corresponding demanganese effect.

[0074] S3. In the RH oxygen blowing process, the demanganese agent is added into the vacuum chamber at one time according to the dosage, and the RH incoming molten steel is demanganese treated to obtain demanganese molten steel.

[0075] In some embodiments, during the RH oxygen blowing process, when the oxygen supply is 10% to 20%, the demanganeseizing agent is added into the vacuum chamber at one time at the upper part of the riser of the vacuum chamber.

[0076] When the oxygen supply is 10% to 20%, the positive effect of adding the demanganese agent into the vacuum chamber at the upper part of the riser of the vacuum chamber at one time is: forming a local high oxidation environment during the RH refining process, and improving the efficiency of the demanganese reaction by improving the high-temperature melt dynamic conditions.

[0077] In some embodiments, the lifting gas of the vacuum chamber is argon gas, and the flow rate of the argon gas is 1400NL / min to 1600NL / min.

[0078] In the process of RH vacuum refining, the blowing of argon is the driving force for the circulation of molten steel. Argon is blown into the molten steel through the riser, forming bubbles and driving the circulation of the molten steel, thereby improving the refining efficiency. This effect of argon helps to remove inclusions, gases and other impurities in the molten steel. By adjusting the flow rate of argon, the circulation of molten steel and the refining effect can be optimized. Exemplarily, the argon flow rate is 1400NL / min, 1460NL / min, 1500NL / min, 1560NL / min, 1600NL / min, etc.

[0079] In some embodiments, the oxygen supply flow rate of the vacuum chamber is 2300m 3 / h~2500m 3 / h, the oxygen supply of the vacuum chamber is 0m 3 ~400m 3 The oxygen lance position of the vacuum chamber is 5.3m to 5.6m.

[0080] Control the oxygen flow rate of the vacuum chamber to 2300m 3 / h~2500m 3 The positive effect of this oxygen flow rate is that it not only helps to improve the dynamic conditions of the molten pool, but also can quickly complete the decarburization task. For example, the oxygen flow rate is 2300m 3 / h、2370m 3 / h、2400m 3 / h、2450m 3 / h、2500m 3 / h, etc.

[0081] Control the oxygen supply in the vacuum chamber to 0m 3 ~400m 3The positive effect is that this oxygen supply can ensure decarburization while ensuring that the oxidizability of the molten pool does not change too much, which helps control the sulfur content in the molten steel. For example, the oxygen supply is 10m 3 、100m 3 、150m 3 、250m 3 、300m 3 、400m 3 wait.

[0082] The oxygen lance position is set within the range of 5.3m to 5.6m, which can ensure that the depth and position of oxygen injection into the molten steel are appropriate. This helps the oxygen to fully contact and react with the molten steel, and improves the efficiency of the demanganese process. At the same time, it can reduce the waste of oxygen and the occurrence of splashing, and improve the stability and safety of the production process. Exemplarily, the oxygen lance position is 5.3m, 5.4m, 5.5m, 5.6m, etc.

[0083] In some embodiments, the ultimate vacuum degree of the vacuum chamber is 0Pa to 67Pa.

[0084] The positive effect of controlling the ultimate vacuum degree of the vacuum chamber to 0Pa to 67Pa: The vacuum degree in the RH refining process is an important factor affecting the demanganese rate. Improving the vacuum degree can reduce the gas partial pressure in the molten steel, thereby enhancing the volatility of elements such as manganese. In addition, under vacuum conditions, the contact between the molten steel and oxygen in the air is reduced, reducing the risk of reoxidation of elements such as manganese. Exemplarily, the ultimate vacuum degree is 0Pa, 23Pa, 33Pa, 40Pa, 50Pa, 60Pa, 67Pa, etc.

[0085] In some embodiments, the C content of the demanganese molten steel is ≤ 0.002% by mass.

[0086] The positive effect of controlling the C content of demanganese steel to ≤0.002%: In demanganese steel, controlling the C content at a lower level can optimize the balance of strength and toughness of the steel.

[0087] In some embodiments, the temperature of the demanganese molten steel is 1570°C to 1590°C.

[0088] The temperature of demanganese molten steel is 1570℃~1590℃ mainly based on the physical and chemical principles and actual production experience in the steel smelting process. This temperature range is set to optimize the demanganese effect while ensuring other quality indicators of molten steel. Within a certain temperature range, the rate of demanganese reaction increases with the increase of temperature. However, too high a temperature may cause the volatilization of other beneficial elements or the increase of harmful elements in the molten steel, so a suitable temperature range needs to be selected. The temperature range of 1570℃~1590°℃ is generally considered to be a range that is conducive to the demanganese reaction. At this temperature, the demanganizing agent can fully melt and react with manganese in the molten steel to form volatile compounds that are easy to separate. In addition to the demanganese effect, other quality indicators of molten steel, such as the content of harmful elements such as sulfur and phosphorus, also need to be controlled. The selection of this temperature range often also takes into account the removal effect of these elements and the overall stability of the molten steel. At this temperature, the molten steel has good fluidity, which is conducive to the floating and removal of inclusions, and also helps to reduce the defects generated by the molten steel during the solidification process. Exemplarily, the temperature of the demanganese molten steel is 1570°C, 1578°C, 1580°C, 1590°C, etc.

[0089] The present application is further described below in conjunction with specific examples. The experimental methods in the following examples that do not specify specific conditions are usually measured according to industry standards; if there are no corresponding industry standards, they are carried out according to common international standards, conventional conditions, or conditions recommended by the manufacturer.

[0090] The composition and basicity of the RH incoming slag, the composition of the RH incoming molten steel and the amount of demanganese agent are shown in Table 1.

[0091] Table 1 Composition (wt%), basicity of RH incoming slag, composition (wt%) of RH incoming molten steel and amount of demanganeseizing agent

[0092] Group CaO MnO TFe Alkalinity R Mn S Demanganeseizing agent dosage (kg / t steel) Example 1 41.2 0.93 19.86 5.67 0.0193 0.0018 0.4 Example 2 40.7 1.00 18.71 5.53 0.0245 0.0015 0.7 Example 3 43.8 0.82 19.03 5.83 0.0271 0.0017 1.0 Comparative Example 1 40.1 1.04 20.78 5.03 0.0178 0.0016 -

[0093] Based on the compositions of the RH incoming slag and the RH incoming molten steel in the embodiment and the comparative example, the embodiment obtains the dosage of the demanganese agent according to the mass fraction of the initial Mn in the RH incoming molten steel; in the RH oxygen blowing process, the demanganese agent is put into the vacuum chamber at one time according to the dosage to obtain the demanganese molten steel.

[0094] The demanganese molten steel obtained in the embodiment and the comparative example was subjected to component analysis, and the results are shown in Table 2.

[0095] Table 2 RH demanganese molten steel composition (wt%) analysis results

[0096] Group End point Mn End S Example 1 0.0133 0.0012 Example 2 0.0121 0.0011 Example 3 0.0093 0.0009 Comparative Example 1 0.0203 0.0013

[0097] It can be seen from Tables 1 and 2 that the composition and basicity of the RH incoming slag, the composition of the RH incoming molten steel and the amount of the demanganizing agent used in the embodiments are all within the required range of the present invention. After the demanganizing agent is added for demanganizing treatment, the end point Mn mass fraction meets the requirements, and effective demanganizing can be achieved in the RH refining process.

[0098] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0099] (1) The iron oxide scale in the embodiment is the iron oxide scale produced by hot rolling, which is a resource utilization of the iron oxide scale in the hot rolling process.

[0100] (2) The demanganeseizing agent in the embodiment can achieve effective demanganeseization in the reducing environment of the ultra-low sulfur industrial pure iron RH refining process, shorten the converter cycle, reduce the production scheduling pressure, and reduce the difficulty of converter endpoint control.

[0101] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features applied for by the present application.

Claims

1. An extremely low sulfur industrial pure iron RH demanganese agent, characterized in that: The raw materials of the demanganese agent include, by weight: 6 to 7 parts of hot-rolled iron oxide scale, 1 to 2 parts of lime and 1 to 2 parts of silica.

2. The demanganizing agent according to claim 1, characterized in that The demanganese agent is spherical, and the diameter of the demanganese agent is 30 mm to 60 mm.

3. The demanganizing agent according to claim 1, characterized in that The particle size of the hot-rolled iron oxide scale is 50 mesh to 100 mesh; and / or, The particle size of the lime is 100-200 mesh; and / or, The particle size of the silica is 100-200 meshes.

4. The demanganizing agent according to claim 1, characterized in that The CaO content of the lime is ≥ 80% by mass; and / or, Calculated by mass fraction, the SiO2 content of the silica is ≥85%.

5. A method for preparing the demanganizing agent according to any one of claims 1 to 4, characterized in that: The method comprises: mixing the hot-rolled iron oxide scale, the lime and the silica according to the weight parts, and pressing them into a spherical shape.

6. A method for using the demanganizing agent according to any one of claims 1 to 4, characterized in that: The method comprises: Control the chemical composition of the RH incoming slag and the RH incoming molten steel to obtain the initial Mn mass fraction of the RH incoming molten steel; According to the mass fraction of the initial Mn, the dosage of the demanganizing agent is obtained; In the RH oxygen blowing process, the demanganese agent is put into the vacuum chamber at one time according to the dosage, and the RH incoming molten steel is demanganese treated to obtain demanganese molten steel.

7. The method according to claim 6, characterized in that The basicity of the RH incoming slag is R≥5.5; and / or, The CaO mass fraction of the RH incoming slag is 40% to 45%; and / or, The MnO mass fraction of the RH incoming slag is ≤1.0%; and / or, The TFe mass fraction of the RH incoming slag is ≤20%; and / or, The S mass fraction of the RH incoming molten steel is ≤0.002%; and / or, The O mass fraction of the RH incoming molten steel is ≤0.0005%; and / or, The inlet temperature of the RH inlet molten steel is 1600°C to 1630°C.

8. The method according to claim 6, characterized in that The amount of the demanganizing agent obtained according to the mass fraction of the initial Mn comprises: If the mass fraction of the initial Mn is ≤0.02%, the amount of the demanganizing agent is 0.4 kg / t steel; If the mass fraction of the initial Mn is 0.02% to 0.025%, the amount of the demanganizing agent is 0.7 kg / t steel; If the mass fraction of the initial Mn is 0.025% to 0.03%, the dosage of the demanganizing agent is 1.0 kg / t steel.

9. The method according to claim 6, characterized in that When the demanganese agent is put into the vacuum chamber at one time, the putting position of the demanganese agent is the upper part of the riser of the vacuum chamber; and / or, The lifting gas of the vacuum chamber is argon gas, and the flow rate of the argon gas is 1400NL / min to 1600NL / min; and / or, The oxygen supply flow rate of the vacuum chamber is 2300m 3 / h~2500m 3 / h, the oxygen supply of the vacuum chamber is 0m 3 ~400m 3 , The oxygen lance position of the vacuum chamber is 5.3m to 5.6m; and / or, The ultimate vacuum degree of the vacuum chamber is 0Pa-67Pa.

10. The method according to claim 56, characterized in that The C content of the demanganese molten steel is ≤0.002% by mass; and / or, The temperature of the demanganese molten steel is 1570°C to 1590°C.

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