Ferrotitanium nitride material and preparation method thereof

Abstract

The invention relates to a ferrotitanium nitride material and a preparation method thereof, and belongs to the field of high-temperature materials. The titanium-iron nitride comprises the following components in percentage by mass: 70%-96% of TiN, 3%-29% of Fe and the balance of impurities. The preparation method comprises the following steps: carrying out crushing pretreatment on ilmenite, uniformly mixing the ilmenite with carbon powder and a resin binder, and pressing into pellets; and the pellets are placed in a graphite crucible, nitrogen is introduced into an intermediate frequency furnace, and electromagnetic induction is utilized for heating. The method comprises the following steps: firstly, heating a graphite crucible to be greater than or equal to 1400 DEG C by utilizing electromagnetic induction, so that pellets in contact with the graphite crucible are subjected to a reduction nitridation reaction to generate a ferrotitanium nitride material; tiN and Fe have good electrical conductivity, the newly generated TiN-Fe is further heated through electromagnetic induction, the reduction nitridation reaction of the internal pellets is promoted, and the reaction is pushed inwards layer by layer till the end. The prepared TiN-Fe material is excellent in erosion resistance and has wide application prospects in the fields of stemming, blast furnace gunning materials and the like, and the preparation process is short in process, short in reaction time and high in efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature materials, and particularly relates to a titanium nitride iron material and a preparation method thereof. Background Art

[0002] TiN has a high melting point, high hardness, good thermal conductivity, is not easily wetted by molten metals and slag, etc., and has excellent chemical stability. It is a non-oxide refractory material with high corrosion resistance and high thermal shock resistance. Ironmaking workers have proven through years of practice that using titanium-containing burden is an effective means to protect the hearth and bottom of the furnace and extend the service life of blast furnaces. The reason is that part of the titanium oxide is reduced during the ironmaking process, and then a slag skin mainly composed of TiN and Ti(C,N) is formed on the furnace wall and bottom of the blast furnace, playing a good role in protecting the furnace. Inspired by this, people introduced TiO2 into the taphole clay system and developed functional titanium-containing taphole clay. When the TiO2-containing taphole clay enters the furnace, TiO2 enters the liquid slag and iron. Especially in the tuyere area, TiO2 in the liquid slag is reduced by carbon to generate TiN or Ti(C,N), which grows by enrichment during sedimentation. This binder with a dense structure, high hardness, thermal resistance and high melting point adheres to the brick lining of the hearth and bottom around the taphole, protecting the hearth and bottom of the taphole area and slowing down the erosion. However, due to frequent high-pressure oxygen blowing and oxygen burning for opening the hole, the reaction of TiO2 to TiN during the service of the taphole clay is relatively difficult or its transformation requires a certain amount of time, resulting in a lag in the furnace protection effect of the taphole clay and making it difficult to exert its furnace protection effect.

[0003] The preparation methods of titanium nitride mainly include TiO2 reduction nitridation method, mechanical ball milling method, high-temperature self-propagating method, microwave synthesis method, etc. The above methods have problems such as high requirements for powder particle size, high synthesis temperature, or high requirements for equipment, resulting in a relatively high synthesis cost of titanium nitride. The high price limits the application of TiN materials in refractory materials such as taphole clay.

[0004] TiN has good electrical conductivity and can achieve electromagnetic induction heating. Based on this, the present invention proposes to use ilmenite, titanium concentrate or high-titanium slag with excellent cost performance as raw materials, use carbon as a reducing agent, and prepare a new type of titanium nitride iron (TiN-Fe) material by sintering through electromagnetic induction heating in an intermediate frequency furnace. Introducing this titanium nitride iron as a raw material into the taphole clay can directly introduce high-quality non-oxide reinforcing phase TiN in the blast furnace taphole clay, improving the service performance and furnace protection effect of the taphole clay. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides a titanium nitride iron material and a preparation method thereof. Using ilmenite and carbon powder with excellent cost performance as raw materials, heat treatment is carried out by means of electromagnetic induction in an intermediate frequency furnace, and a titanium nitride iron material is prepared through a carbothermal reduction nitridation reaction.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] A titanium nitride iron material, which comprises components in the following mass percentages: 70% - 96% of TiN, 3% - 29% of Fe, and the rest are impurities such as Si, Mg, C, etc.

[0008] Furthermore, the raw materials for preparing the titanium nitride iron material are a titanium source and carbon powder, and the binder is phenolic resin; the particle size of the titanium source ≤ 2 mm, and the particle size of the carbon powder ≤ 0.1 mm.

[0009] Furthermore, the titanium source contains TiO₂ and Fe₂O₃, and is selected from at least one of ilmenite, titanium concentrate, and high-titanium slag.

[0010] Furthermore, the chemical composition of the titanium source by mass percentage is: TiO₂ ≥ 40%, Fe₂O₃ ≤ 50%, SiO₂ ≤ 1%, Al₂O₃ ≤ 1%, CaO ≤ 0.2%, MgO ≤ 0.3%, MnO ≤ 1.5%; the carbon powder includes but is not limited to carbon black, graphite, carbon nanotubes, etc.

[0011] Furthermore, the main phase components of the titanium source are TiO₂ and Fe₂O₃. When the carbon powder is used as a reducing agent, the following reactions occur: 2TiO₂ + 4C + N₂ = 2TiN + 4CO; Fe₂O₃ + 3C = 2Fe + 3CO. The mass ratio of the titanium source to the carbon powder is calculated according to the reaction formula ratio. Denote the mass percentage content of TiO₂ in the titanium source as x, and the mass percentage content of Fe₂O₃ as y. The mass ratio of the titanium source to the carbon powder is 1:(0.3x + 0.225y); the addition amount of the binder is 0.5% - 5% of the total mass of the titanium source and the carbon powder.

[0012] The preparation method of the titanium nitride iron material is as follows: Weigh the titanium source and carbon powder in proportion, add the phenolic resin binder, mix evenly and then press into pellets; Place the pellets in a graphite crucible, and sinter them in a medium-frequency furnace under a nitrogen atmosphere using the principle of electromagnetic induction heating.

[0013] Furthermore, the preparation method of the titanium nitride iron material includes the following steps:

[0014] (1) Weigh the titanium source, carbon powder, and binder according to the ratio, stir evenly, and press into pellets;

[0015] (2) Place the pellets in step (1) in a graphite crucible, introduce flowing nitrogen in a medium-frequency furnace, and sinter them by electrifying and using electromagnetic induction heating. After the reaction is complete, the titanium nitride iron material is obtained.

[0016] Furthermore, in step (1), first co-grind and premix the titanium source and carbon powder to obtain a mixed powder, and then stir the mixed powder with the phenolic resin binder until evenly mixed.

[0017] Further, the control parameters for electromagnetic induction heating sintering in step (2) are as follows: the N2 content in the nitrogen atmosphere is ≥99.5%, the electromagnetic induction frequency is ≥1000 Hz, the sintering temperature is 1400 - 1800 °C, and the sintering time is 10 - 120 min.

[0018] The present invention also provides a titanium nitride iron material obtained by using the preparation method of the present invention, which has excellent thermal shock resistance and erosion resistance.

[0019] Beneficial effects: Aiming at the problems existing in the prior art, such as high cost of TiN raw materials and unsuitability for refractory materials, the present invention selects ilmenite, titanium concentrate or high-titanium slag with excellent cost performance as raw materials, uses carbon as a reducing agent, and realizes the efficient synthesis of a new type of TiN-Fe material by means of intermediate frequency furnace electromagnetic induction heating technology. Specifically as follows:

[0020] (1) Using ilmenite, titanium concentrate or high-titanium slag as raw materials has a high raw material cost advantage.

[0021] (2) Using a graphite crucible as both a container and a heating element, the graphite crucible is first heated by electromagnetic induction, and the outer pellets are heated by heat conduction and heat radiation to initiate the carbothermal reduction nitridation reaction of TiO2 and Fe2O3 to generate TiN-Fe. TiN and Fe have excellent electrical conductivity. Under the action of the electromagnetic induction coil, the newly formed TiN-Fe on the outer layer forms a new heating element, providing heat for the internal pellets and promoting their carbothermal reduction nitridation reaction. The newly formed TiN-Fe forms a new heating element again, promoting the reaction gradient to gradually advance layer by layer inward until the reaction is completed. The present invention makes full use of the excellent electrical conductivity of TiN-Fe and prepares a new type of TiN-Fe material in one step by electromagnetic induction heating. Its process flow is short, the reaction time is short, the production efficiency is greatly improved, and the energy consumption in the production process is reduced.

[0022] (3) Under the action of the electromagnetic induction coil, eddy currents are generated inside the TiN-Fe material, forming self-heating. The electromagnetic induction heating is used for heat preservation, and it promotes the uniform distribution of Fe in the TiN matrix in an island-like shape, which can further realize the densification sintering of the TiN-Fe material and obtain a new type of titanium nitride iron material.

[0023] (4) The new type of titanium nitride iron material synthesized by the present invention has high cost performance, good chemical stability, excellent thermal shock resistance and erosion resistance.

[0024] (5) The raw materials of the present invention are rich and have excellent cost performance. The preparation method is simple, the process flow is short, the energy consumption is low, the production efficiency is high, and it is suitable for industrial production. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0026] Figure 1 It is the flowchart of the preparation method of the present invention;

[0027] Figure 2 It is the XRD pattern of the prepared ferro-titanium nitride in Example 1. Specific embodiments

[0028] In order to make the invention purpose, technical solutions and beneficial technical effects of the present invention clearer, the following details the present invention with specific embodiments. It should be understood that the embodiments described in this specification are only for explaining the present invention and not for limiting the present invention.

[0029] Example 1

[0030] Using ilmenite with a TiO2 content of 53.6 wt.% and an Fe2O3 content of 43.8 wt.%, and carbon black with a particle size ≤ 1 μm as raw materials, the ratio is ilmenite: carbon black = 1:0.26. The addition amount of phenolic resin binder is 2% of the total mass of titania corundum and carbon black. Mix the ilmenite, carbon black and phenolic resin binder evenly and press them into pellets with a diameter of about 5 cm. Place the pellets in a graphite crucible, introduce flowing nitrogen in an intermediate frequency furnace, and carry out nitriding sintering by electromagnetic induction heating. The control parameters are: the N2 content in the nitrogen atmosphere ≥ 99.5%, the electromagnetic induction frequency is 1000 Hz, the sintering temperature is 1500 °C, and the sintering time is 30 min to obtain the ferro-titanium nitride material. The flowchart of its preparation method is as Figure 1 shown.

[0031] The obtained ferro-titanium nitride material is detected, and the main phase composition is TiN and Fe.

[0032] Example 2

[0033] Using ilmenite with a TiO2 content of 40.0 wt.% and an Fe2O3 content of 57.8 wt.%, and carbon black with a particle size ≤ 1 μm as raw materials, the ratio of ilmenite to carbon black is 1:0.25, and the addition amount of phenolic resin binder is 3% of the total mass of titania corundum and carbon black. Mix the ilmenite, carbon black and phenolic resin binder evenly and press them into pellets with a diameter of about 5 cm. Place the pellets in a graphite crucible, introduce flowing nitrogen in an intermediate frequency furnace, and carry out nitriding sintering by electromagnetic induction heating. The control parameters are: the N2 content in the nitrogen atmosphere ≥ 99.5%, the electromagnetic induction frequency is 2000 Hz, the sintering temperature is 1700 °C, and the sintering time is 10 min to obtain the titanium nitride iron material.

[0034] The obtained titanium nitride iron material is detected, and the main phase composition is TiN and Fe.

[0035] Example 3

[0036] Using titanium concentrate with a TiO2 content of 60.5 wt.% and an Fe2O3 content of 36.9 wt.%, and graphite with a particle size ≤ 5 μm as raw materials, the ratio of titanium concentrate to graphite is 1:0.26, and the addition amount of phenolic resin binder is 5% of the total mass of titanium concentrate and graphite. Mix the titanium concentrate, graphite and phenolic resin binder evenly and press them into pellets with a diameter of about 5 cm. Place the pellets in a graphite crucible, introduce flowing nitrogen in an intermediate frequency furnace, and carry out nitriding sintering by electromagnetic induction heating. The control parameters are: the N2 content in the nitrogen atmosphere ≥ 99.5%, the electromagnetic induction frequency is 1500 Hz, the sintering temperature is 1600 °C, and the sintering time is 80 min to obtain the titanium nitride iron material.

[0037] The obtained titanium nitride iron material is detected, and the main phase composition is TiN and Fe.

[0038] Example 4

[0039] Using high-titanium slag with a TiO2 content of 85.0 wt.% and an Fe2O3 content of 11.5 wt.%, and carbon black with a particle size ≤ 3 μm as raw materials, the ratio of high-titanium slag to carbon black is 1:0.26, and the addition amount of phenolic resin binder is 2% of the total mass of high-titanium slag and carbon black. Mix the high-titanium slag, carbon black and phenolic resin binder evenly and press them into pellets with a diameter of about 5 cm. Place the pellets in a graphite crucible, introduce flowing nitrogen in an intermediate frequency furnace, and carry out nitriding sintering by electromagnetic induction heating. The control parameters are: the N2 content in the nitrogen atmosphere ≥ 99.5%, the electromagnetic induction frequency is 1000 Hz, the sintering temperature is 1500 °C, and the sintering time is 30 min to obtain the titanium nitride iron material.

[0040] The obtained titanium nitride iron material is detected, and the main phase composition is TiN and Fe.

[0041] Example 5

[0042] Using high-titanium slag with a TiO2 content of 93.4 wt.% and an Fe2O3 content of 3.9 wt.%, and carbon black with a particle size ≤ 3 μm as raw materials, the ratio of high-titanium slag to carbon black is 1:0.26, and the addition amount of phenolic resin binder is 2% of the total mass of high-titanium slag and carbon black. Mix the high-titanium slag, carbon black, and phenolic resin binder evenly and press them into pellets with a diameter of about 5 cm. Place the pellets in a graphite crucible, introduce flowing nitrogen in an intermediate-frequency furnace, and carry out nitriding sintering by electromagnetic induction heating. The controlled parameters are: the N2 content in the nitrogen atmosphere ≥ 99.5%, the electromagnetic induction frequency is 1000 Hz, the sintering temperature is 1500 °C, and the sintering time is 120 min to obtain the titanium nitride iron material.

[0043] The obtained titanium nitride iron material is detected, and the main phase composition is TiN and Fe.

[0044] Comparative Example 1

[0045] Using high-titanium slag with a TiO2 content of 93.4 wt.% and an Fe2O3 content of 3.9 wt.%, and carbon black with a particle size ≤ 3 μm as raw materials, the ratio of high-titanium slag to carbon black is 1:0.26, and the addition amount of phenolic resin binder is 2% of the total mass of high-titanium slag and carbon black. Mix the high-titanium slag, carbon black, and phenolic resin binder evenly and press them into pellets with a diameter of about 5 cm. Place the pellets in a graphite crucible, introduce flowing nitrogen in a high-temperature sintering furnace, and carry out nitriding sintering. The controlled parameters are: the N2 content in the nitrogen atmosphere ≥ 99.5%, the sintering temperature is 1500 °C, and the sintering time is 120 min to obtain the product.

[0046] The obtained product is detected, and the main phase composition is TiO2, FeO, TiN, and Fe. It shows that the titanium nitride iron material cannot be obtained by the conventional sintering method.

[0047] In the solution of the present invention, the graphite crucible serves as both a container and a heating element. After the intermediate-frequency furnace is powered on, the magnetic field generated by the coil passes through the graphite crucible, causing eddy currents to be generated inside the graphite crucible, and the temperature rises rapidly; when the temperature reaches 1400 °C, the pellets in contact with the graphite crucible first undergo carbothermal reduction nitridation reactions: TiO2(s)+C(s)+N2(g)→TiN(s)+CO(g), Fe2O3(s)+C(g) →Fe(s,l)+CO(g), generating TiN and Fe; since both TiN and Fe have excellent electrical conductivity, under the action of the electromagnetic induction coil, the newly formed TiN-Fe is rapidly heated, generating a large amount of heat, thereby further promoting the carbothermal reduction nitridation reaction of the internal pellets; the formation reaction of TiN-Fe diffuses layer by layer inward until the reaction ends, and the pellets are completely converted into the TiN-Fe material.

[0048] The XRD pattern of the titanium iron nitride material synthesized in Example 1 is as follows Figure 2 shown. The pellets sintered in Example 1 were crushed as a whole to make 200-mesh fine powder, and the results of its X-ray diffraction analysis are as follows Figure 2 shown, and its crystal phase composition is TiN and Fe.

[0049] As mentioned above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope determined by the claims.

Claims

1. A titanium nitride iron material, characterized in that, It comprises components in the following mass percentages: 70% - 96% of TiN, 3% - 29% of Fe, and the rest are impurities.

2. The titanium nitride iron material according to claim 1, characterized in that, The raw materials for preparing the titanium nitride iron material are a titanium source and carbon powder, and the binder is phenolic resin; the particle size of the titanium source is ≤ 2 mm, and the particle size of the carbon powder is ≤ 0.1 mm.

3. The titanium nitride iron material according to claim 2, wherein The titanium source contains TiO₂ and Fe₂O₃ and is selected from at least one of ilmenite, titanium concentrate, and high-titanium slag.

4. The titanium nitride iron material according to claim 3, characterized in that, The chemical composition of the titanium source is by mass percentage: TiO₂ ≥ 40%, Fe₂O₃ ≤ 50%, SiO₂ ≤ 1%, Al₂O₃ ≤ 1%, CaO ≤ 0.2%, MgO ≤ 0.3%, MnO ≤ 1.5%; the carbon powder is selected from carbon black, graphite, and carbon nanotubes.

5. The titanium nitride iron material according to claim 3, characterized in that, The mass percentage content of TiO₂ in the titanium source is denoted as x, and the mass percentage content of Fe₂O₃ is denoted as y. The mass ratio of the titanium source to the carbon powder is 1:(0.3x + 0.225y); the addition amount of the binder is 0.5% - 5% of the total mass of the titanium source and the carbon powder.

6. The preparation method of the titanium nitride iron material according to any one of claims 1 to 5, characterized in that, It includes the following steps: (1) Weigh the titanium source, carbon powder, and binder according to the ratio, stir evenly, and press into pellets. (2) Place the pellets in step (1) in a graphite crucible, introduce flowing nitrogen in a medium-frequency furnace, and conduct sintering by energizing and using electromagnetic induction heating. After the reaction is complete, the titanium nitride iron material is obtained.

7. The preparation method of the titanium nitride iron material according to claim 6, characterized in that, In step (1), first, the titanium source and the carbon powder are co-ground and premixed to obtain a mixed powder, and then the mixed powder and the binder phenolic resin are stirred until evenly mixed.

8. The preparation method of the ferro-titanium nitride material according to claim 6, wherein, The control parameters for the electromagnetic induction heating sintering in step (2) are: the N₂ content in the nitrogen atmosphere is ≥ 99.5%, the electromagnetic induction frequency is ≥ 1000 Hz, the sintering temperature is 1400 - 1800 °C, and the sintering time is 10 - 120 min.

9. A titanium nitride iron material, characterized in that, Obtained by using the preparation method according to any one of claims 6 to 8.

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