Method for preparing ferrotitanium alloy by taking melt separation titanium slag and vanadium-titanium metallized pellets as raw materials

Abstract

The invention belongs to the technical field of metallurgy, and particularly discloses a method for preparing a ferrotitanium alloy by using melt separation titanium slag and vanadium-titanium metallized pellets as raw materials, which comprises the following steps: S1, proportioning and mixing the melt separation titanium slag, the vanadium-titanium metallized pellets, an aluminum reducing agent and a slag former as raw materials according to the chemical components of the target ferrotitanium alloy to obtain a charging material; s2, the charging material is subjected to high-temperature smelting; and S3, after smelting is finished, cooling to room temperature, crushing slag shells, and performing slag-metal separation to obtain the ferrotitanium alloy. According to the method, the molten titanium slag is externally matched with the vanadium-titanium metallized pellets, the ferrotitanium alloy is directly prepared by adopting an aluminothermic reduction process one-step method in auxiliary heating modes such as electric heating, two vanadium-titanium secondary resources are cooperatively treated, and the method has the advantages of being short in technological process, low in production cost, good in slag-metal separation, high in yield of elements such as ferrotitanium and the like and the like, and is suitable for industrial application.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and in particular to a method for preparing titanium-iron alloys using molten titanium slag and vanadium-titanium metallized pellets as raw materials. Background Technology

[0002] After smelting vanadium-titanium magnetite using blast furnace or non-blast furnace processes, a large amount of titanium-containing blast furnace slag or molten titanium slag is produced. The titanium oxide (mainly TiO2) content in this type of slag is typically >20%, making it an important secondary titanium resource. Currently, the resource utilization of this type of titanium slag mainly focuses on extracting titanium, such as producing titanium dioxide or sponge titanium through the sulfuric acid process or chloride process. However, this process suffers from problems such as long processing time, high energy consumption, and large emissions of waste gas, wastewater, and solid waste.

[0003] Pyrometallurgy, especially the aluminothermic reduction method, is a potential route for directly preparing titanium-iron alloys from titanium slag. Titanium-iron alloys are important steel additives. When using the traditional aluminothermic method to directly reduce high-titanium slag to prepare titanium-iron alloys, the following problems are mainly faced: (1) The reaction is violently exothermic, and the furnace temperature is extremely high. The theoretical temperature of the reaction zone can reach 1800~2000℃, which easily causes splashing and titanium burn-off and alloy segregation; (2) The aluminothermic reduction reaction occurs instantaneously, and the resulting titanium-iron alloy metal droplets have a short settling time, making it difficult to effectively aggregate, settle, and completely separate from the slag, resulting in difficulty in slag-metal separation and low alloy yield. After slag breaking, a large number of fine metal beads can be observed to be wrapped or embedded in the slag phase, forming a "metal-slag" mixture. Moreover, the heat provided by the aluminothermic self-propagation is limited, making it difficult to maintain the continuous chemical reaction, which also affects the alloy yield. (3) To reduce impurities such as carbon, sulfur, and phosphorus in the alloy, expensive titanium concentrate or high-titanium slag is usually required as raw material, resulting in high costs; (4) The intermediate product of the direct reduction process of vanadium-titanium magnetite—vanadium-titanium metallized pellets—was not utilized in conjunction with the process. Vanadium-titanium metallized pellets are products obtained by direct reduction of vanadium-titanium magnetite through gas-based or coal-based processes. They have high iron content, high metallization rate, and contain a certain amount of vanadium and titanium. They are high-quality raw materials for short-process steelmaking. Treating them together with titanium slag may have better resource and economic value.

[0004] In the existing technology, there is a lack of technical solutions that can organically combine molten titanium slag with vanadium-titanium metallized pellets to directly prepare medium-low titanium iron alloys through aluminothermic reduction process, while maximizing the recovery of iron and titanium elements. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for preparing titanium-iron alloys using molten titanium slag and vanadium-titanium metallized pellets as raw materials. The method organically combines molten titanium slag with vanadium-titanium metallized pellets and directly prepares titanium-iron alloys through an aluminothermic reduction process. The process is short, the raw material cost is low, and the recovery of iron and titanium elements can be maximized, making it suitable for industrial applications.

[0006] To achieve the above and other related objectives, the present invention provides a method for preparing titanium-iron alloys using molten titanium slag and vanadium-titanium metallized pellets as raw materials, comprising the following steps:

[0007] S1. Using molten titanium slag, vanadium-titanium metallized pellets, aluminum reducing agent and slag-forming agent as raw materials, the materials are batched and mixed according to the chemical composition and content of the target titanium-iron alloy to obtain the furnace feed. S2. The furnace feed material is smelted at high temperature; S3. After smelting, cool to room temperature, break the slag shell, and separate the slag and gold to obtain titanium-iron alloy.

[0008] Furthermore, in step S1, the molten titanium slag contains 20% to 75% TiO2 by mass.

[0009] Furthermore, in step S1, the vanadium-titanium metallized pellets are obtained by reducing vanadium-titanium ore in a hydrogen-based vertical shaft furnace.

[0010] Furthermore, in step S1, the metallization rate of the vanadium-titanium metallized pellets is equal to or higher than 80%.

[0011] Furthermore, in step S1, the aluminum reducing agent is aluminum granules and / or aluminum shavings.

[0012] Furthermore, in step S1, during the batching process, an excess of aluminum reducing agent is added; preferably, the actual amount of aluminum reducing agent added is 1.2 to 1.5 times the theoretical amount of aluminum reducing agent required to reduce the reducible oxides in the molten titanium slag.

[0013] Furthermore, in step S1, the slag-forming agent is a calcium-based slag-forming agent, which is selected from at least one of calcium oxide and calcium fluoride, and / or the mass fraction of the slag-forming agent in the furnace feed is 5% to 35%.

[0014] Furthermore, in step S2, the smelting is carried out under an inert atmosphere.

[0015] Furthermore, in step S2, the smelting process is carried out with a gradient temperature increase according to a preset temperature rise curve.

[0016] Furthermore, in step S2, the smelting temperature is 1400~1800℃.

[0017] Furthermore, in step S2, the smelting process is carried out in a gradient heating process according to a preset heating curve, including: in the first stage, the temperature is raised to 1100~1300℃ and then held for 0.5~1h; in the second stage, the temperature is raised to 1400~1800℃ and then held for 1~2h.

[0018] Furthermore, in step S2, the smelting process is subjected to gradient heating according to a preset heating curve under auxiliary heating means, which includes, but is not limited to, electric heating.

[0019] Furthermore, in step S3, after smelting is completed, heating is stopped and the furnace is cooled to room temperature.

[0020] Furthermore, in step S3, the obtained titanium-iron alloy contains the following chemical composition by mass fraction: Ti 25.0%~45.0%, Fe 30.0%~50.0%.

[0021] Furthermore, in step S1, the target titanium-iron alloy is a titanium-iron alloy conforming to the national standard GB / T3282-2012, with the grade FeTi30 or FeTi40.

[0022] As described above, the method for preparing titanium-iron alloys using molten titanium slag and vanadium-titanium metallized pellets as raw materials of the present invention has the following beneficial effects: 1) Resource synergy and maximum utilization: It realizes the synergistic processing of two secondary vanadium and titanium resources, namely molten titanium slag (titanium resource) and vanadium-titanium metallized pellets (iron resource), while efficiently recovering valuable elements such as titanium and iron, which is in line with the concept of circular economy.

[0023] 2) Heat self-sufficiency and temperature control: Aluminum is used as a reducing agent, and some heat energy is generated by the aluminothermic self-propagating reaction. However, the released heat is limited and it is difficult to maintain a stable temperature field, which is not conducive to the continuous progress of the chemical reaction. Therefore, by adding auxiliary heating methods such as electric heating to carry out gradient heating, not only can the insufficient heat of reaction be made up to provide sufficient heat for the reduction process, so that the reaction can proceed fully, ensuring the polymerization and sedimentation of alloy droplets to achieve good slag-gold separation and thus obtain a high element yield, but also to achieve precise temperature control, thereby significantly improving the overall energy utilization efficiency.

[0024] 3) Controllable alloy composition: By accurately calculating the ratio of molten titanium slag to vanadium-titanium metallized pellets, production can be directly targeted at titanium-iron alloy grades with high market demand, such as FeTi30 and FeTi40.

[0025] 4) Short process, low cost, and high alloy yield: Compared to the traditional long process of "titanium slag-purification-chlorination / sulfuric acid method-titanium product" or "rutile aluminothermic method," this invention directly prepares titanium-iron alloys in one step, significantly shortening the process flow. It directly uses widely available and inexpensive molten titanium slag and vanadium-titanium metallized pellets as raw materials, greatly reducing production costs. Furthermore, by introducing auxiliary heating methods such as electric heating, slag-metal separation is significantly promoted, thereby ensuring a high alloy yield. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0027] In the attached diagram: Figure 1 This is a schematic diagram of the process flow for preparing titanium-iron alloys using molten titanium slag and vanadium-titanium metallized pellets as raw materials, as provided in the embodiments / examples of the present invention. Figure 2 These are the preset heating curves in Embodiments 1 and 2 of the present invention. Detailed Implementation

[0028] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] In this invention, unless otherwise stated, the term "a plurality of" means two or more.

[0030] The character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0031] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0032] Please see Figure 1 An embodiment of the present invention provides a method for preparing titanium-iron alloys using molten titanium slag and vanadium-titanium metallized pellets as raw materials, comprising the following steps: S1. Using molten titanium slag, vanadium-titanium metallized pellets, aluminum reducing agent and slag-forming agent as raw materials, the molten titanium slag and vanadium-titanium metallized pellets are crushed and ground to a predetermined particle size. Then, according to the chemical composition and content of the target titanium-iron alloy, combined with thermodynamic analysis, the materials are batched and mixed to obtain the furnace feed. S2. The furnace feed material is smelted at high temperature; S3. After smelting, cool to room temperature, break the slag shell, and separate the slag and gold to obtain titanium-iron alloy.

[0033] The above-described implementation method directly prepares titanium-iron alloys in one step by combining vanadium-titanium metallized pellets with molten titanium slag and using an aluminothermic reduction process. This method synergistically processes two secondary vanadium-titanium resources, which not only significantly reduces raw material costs but also shortens the process flow. Furthermore, the slag and alloy are easily separated, and the recovery rates of elements such as titanium and iron are high, with Ti recovery rates exceeding 70% and Fe recovery rates exceeding 97%.

[0034] In some embodiments of the present invention, in step S1, the molten titanium slag contains 20% to 75% TiO2 by mass; the vanadium-titanium metallized pellets are obtained by reducing vanadium-titanium ore in a hydrogen-based vertical shaft furnace, and the metallization rate is preferably not less than 80%; the aluminum reducing agent is aluminum granules or aluminum shavings, and an excess of aluminum reducing agent is added during batching to ensure sufficient reduction, while the exothermic reaction of the excess aluminum is used to maintain the reaction temperature. Preferably, the actual amount of aluminum reducing agent added is 1.2 to 1.5 times the theoretical amount of aluminum reducing agent required to reduce the reducible oxides (such as TiO2) in the molten titanium slag.

[0035] In some embodiments of the present invention, in step S1, the slag-forming agent is a calcium-based slag-forming agent, which includes, but is not limited to, one or more combinations of calcium oxide (CaO), calcium fluoride (CaF2), etc., and its addition amount accounts for 5% to 35% of the total mass of the furnace feed.

[0036] In some embodiments of the present invention, in step S2, the reaction apparatus is a smelting furnace with an atmosphere protection and vacuum system. The smelting furnace can be a vacuum resistance furnace or a vacuum induction furnace, but is not limited to these. When using a vacuum resistance furnace, the heater can be made of silicon molybdenum rods; when using a vacuum induction furnace, a graphite crucible can be used as the reaction vessel. Smelting is carried out under an inert atmosphere, such as argon or nitrogen, but is not limited to these. The smelting process is carried out with a gradient heating according to a preset heating curve under auxiliary heating to promote slag-metal separation and improve alloy yield. The smelting temperature is, for example, 1400~1800℃. The auxiliary heating means include, but is not limited to, electric heating. For example, the gradient heating process includes: a first stage of heating to 1100~1300℃ and holding for 0.5~1h, preferably 0.5h; a second stage of continuing to heat to 1400~1800℃ and holding for 1~2h, preferably 1h. The heating rates for the first and second stages are, for example, 5~10℃ / min and 3~6℃ / min, respectively.

[0037] In some embodiments of the present invention, in step S3, after smelting is completed, heating is stopped (i.e., the heating system is turned off), and the material is allowed to cool to room temperature with the furnace. After cooling to room temperature, the solidified slag shell is broken, and the ferro-titanium alloy ingot and waste slag are separated and removed; the ferro-titanium alloy ingot is cleaned to obtain the ferro-titanium alloy product.

[0038] In some embodiments of the present invention, in step S1, the target ferrotitanium alloy is a ferrotitanium alloy conforming to the national standard GB / T3282-2012, with the grade FeTi30 or FeTi40, including FeTi30-A, FeTi30-B, FeTi40-A, and FeTi40-B. This type of ferrotitanium alloy is a medium-low ferrotitanium alloy. In step S3, the obtained ferrotitanium alloy contains the following chemical composition by mass fraction: titanium (Ti) 25.0%~45.0%, iron (Fe) 30.0%~50.0%. In addition, the obtained ferrotitanium alloy also contains other chemical components, such as carbon (C), silicon (Si), phosphorus (P), sulfur (S), aluminum (Al), manganese (Mn), copper (Cu), etc., but is not limited to these. Preferably, the obtained ferrotitanium alloy conforms to the requirements of the national standard GB / T3282-2012 for ferrotitanium alloys with the grade FeTi30 or FeTi40.

[0039] The following specific examples illustrate the present invention in detail. It should also be understood that the following examples are only for specific illustrative purposes and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0040] Example 1 This embodiment prepares a FeTi30 titanium-iron alloy, and the specific implementation process is as follows: Using 100g of molten titanium slag, 32.79g of vanadium-titanium metallized pellets, 45.84g of aluminum granules, 75.96g of lime, and 3.80g of fluorite as raw materials, mix them evenly in the specified proportions and then feed them into the furnace. Open the inlet gas valve and purge the furnace with argon gas to replace the gas inside. Once the furnace reaches an inert atmosphere, proceed according to... Figure 2 The smelting process is carried out according to the preset heating curve conditions shown. After smelting, the sample is taken out after cooling to room temperature in the furnace, the solidified slag shell is broken, and the waste slag is removed to obtain the alloy ingot.

[0041] A small sample of alloy ingots was randomly taken for composition analysis. The analysis by inductively coupled plasma mass spectrometry (ICP) showed that the Ti content in the sample was 26.00%, with a yield of 75.17%, and the Fe content was 46.46%, with a yield of 98.82%. The content of impurity elements was within the standard, which meets the requirements of the national standard GB / T3282-2012 for the grade FeTi30-B titanium-iron alloy.

[0042] Example 2 This embodiment prepares a FeTi40 titanium-iron alloy, and the specific implementation process is as follows: Using 100g of molten titanium slag, 13.84g of vanadium-titanium metallized pellets, 42.50g of aluminum granules, 70.21g of lime, and 3.51g of fluorite as raw materials, mix them evenly in the specified proportions and then feed them into the furnace. Open the inlet gas pipeline valve and purge the furnace gas with argon. Once the furnace reaches an inert atmosphere, proceed according to... Figure 2 The smelting process is carried out according to the preset heating curve conditions shown. After smelting, the sample is taken out after cooling to room temperature in the furnace, the solidified slag shell is broken, and the waste slag is removed to obtain the alloy ingot.

[0043] A small number of alloy ingots were randomly sampled for composition analysis. ICP analysis revealed that the Ti element content in the sample was 38.98%, with a yield of 73.79%, and the Fe element content was 35.58%, with a yield of 97.44%. The content of impurity elements met the standards and complied with the requirements of the national standard GB / T3282-2012 for the grade FeTi40-B titanium-iron alloy.

[0044] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing titanium-iron alloys using molten titanium slag and vanadium-titanium metallized pellets as raw materials, characterized in that, Includes the following steps: S1. Using molten titanium slag, vanadium-titanium metallized pellets, aluminum reducing agent and slag-forming agent as raw materials, the materials are batched and mixed according to the chemical composition and content of the target titanium-iron alloy to obtain the furnace feed. S2. The furnace feed material is smelted at high temperature; S3. After smelting, cool to room temperature, break the slag shell, and separate the slag and gold to obtain titanium-iron alloy.

2. The method for preparing titanium-iron alloy according to claim 1, characterized in that: In step S1, the molten titanium slag contains 20% to 75% TiO2 by mass. And / or, the vanadium-titanium metallized pellets are obtained by reducing vanadium-titanium ore in a hydrogen-based vertical shaft furnace; And / or, the metallization rate of the vanadium-titanium metallized pellets is equal to or greater than 80%; And / or, the aluminum reducing agent is aluminum granules and / or aluminum shavings; And / or, during ingredient preparation, an excess of aluminum reducing agent is added.

3. The method for preparing titanium-iron alloy according to claim 2, characterized in that: In step S1, the actual amount of aluminum reducing agent added is 1.2 to 1.5 times the theoretical amount of aluminum reducing agent required to reduce the reducible oxides in the molten titanium slag.

4. The method for preparing titanium-iron alloy according to claim 1, characterized in that: In step S1, the slag-forming agent is a calcium-based slag-forming agent; And / or, the mass fraction of the slagging agent in the furnace feed is 5% to 35%.

5. The method for preparing titanium-iron alloy according to claim 4, characterized in that: The calcium-based slag-forming agent is selected from calcium oxide and / or calcium fluoride.

6. The method for preparing titanium-iron alloy according to claim 1, characterized in that: In step S2, smelting is carried out under an inert atmosphere; And / or, the smelting process is carried out with a gradient heating according to a preset heating curve; And / or, the smelting temperature is 1400~1800℃.

7. The method for preparing titanium-iron alloy according to claim 6, characterized in that: In step S2, the smelting process is carried out in a gradient heating according to the preset heating curve, including: the first stage of heating to 1100~1300℃ and holding for 0.5~1h, and the second stage of heating to 1400~1800℃ and holding for 1~2h. And / or, the smelting process is carried out with gradient heating according to a preset heating curve under auxiliary heating means.

8. The method for preparing titanium-iron alloy according to claim 1, characterized in that: In step S3, after smelting is completed, heating is stopped and the furnace is cooled to room temperature.

9. The method for preparing titanium-iron alloy according to any one of claims 1 to 8, characterized in that: In step S3, the resulting titanium-iron alloy contains the following chemical composition by mass fraction: Ti 25.0%~45.0%, Fe 30.0%~50.0%.

10. The method for preparing titanium-iron alloy according to claim 9, characterized in that: In step S1, the target titanium-iron alloy is a titanium-iron alloy conforming to the national standard GB / T3282-2012, with the grade FeTi30 or FeTi40.

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