A method for processing vanadium titano-magnetite to produce ferro-titanium alloy

Abstract

The application provides a method for processing vanadium-titanium magnetite to obtain ferrotitanium alloy, and relates to the field of molten salt electrolytic metallurgy. The method comprises the following steps: mixing a titanium-containing raw material and a molten salt and heating and melting to obtain a molten electrolyte, taking liquid molten iron as a cathode, and taking an inert conductive material as an anode material, and performing electrolysis in the molten electrolyte. Ferrotitanium alloy is obtained; wherein the molten salt is a CaO-SiO2-CaF2 ternary system. The method realizes efficient and short-process preparation of ferrotitanium alloy from titanium ore raw materials, and provides a theoretical and technical basis for efficient, low-cost and green preparation of metallic titanium.

Description

Technical Field

[0001] This invention belongs to the field of molten salt electrolytic metallurgy, and specifically relates to a method for processing vanadium-titanium magnetite to produce titanium-iron alloy. Background Technology

[0002] Molten salt electrolysis is an important technology for extracting and synthesizing metal materials. It is a key process in the production of aluminum and a major technology for producing magnesium, lithium, and rare earth elements. Molten salt electrolysis also holds great promise for the preparation of titanium and titanium-based materials, potentially solving problems such as long process flows and high costs in current titanium production, and enabling the application of titanium materials with excellent physicochemical properties in more fields.

[0003] Currently, methods for electrolyzing metallic titanium using molten salt mainly include molten salt electrodeoxidation, molten salt electrolysis of TOC composite anodes, molten salt electrolysis of dissolved titanium ions such as K2TiF6, and molten salt electrolysis of molten oxides. However, molten salt electrodeoxidation suffers from problems such as the reaction only occurring at the electrode-oxide-molten salt three-phase interface and slow diffusion rate of oxygen ions in the solid phase; molten salt electrode TOC composite anodes require pre-fabrication of the anode and also suffer from disproportionation reactions of polyvalent titanium ions, severely affecting reaction current efficiency and titanium yield; molten salt electrolysis of K2TiF6 requires expensive raw materials and also suffers from disproportionation reactions of polyvalent titanium ions, affecting the reaction process. Molten salt electrolysis of molten oxides is a metallurgical technology proposed by scientists at MIT. In this process, the oxides are all in a molten state, which can avoid the kinetic bottleneck of solid-phase mass transfer and has advantages such as simple process and short process. However, the preparation of metallic titanium by molten salt electrolysis of molten oxides also faces challenges such as selecting an effective molten system to improve the solubility of TiO2 and avoid disproportionation reactions of polyvalent titanium oxides.

[0004] The aforementioned technologies mostly use pure TiO2 as the reaction raw material, still requiring processes such as smelting, chlorination, and acid leaching of ilmenite to obtain TiO2 before titanium extraction. This involves complex processes, high energy consumption, and high pollution. Therefore, further development of technologies for the direct electrolytic preparation of titanium metal and alloys from titanium raw materials such as titanium concentrate and high-titanium slag is essential.

[0005] Chinese patent CN118745584A discloses a method for preparing metallic titanium and / or titanium alloys by molten salt electrolysis. This method uses porous iron as a solid cathode and CaF2-CaO-TiO2-SiO2 as the molten salt electrolyte for electrolysis. This method utilizes the large specific surface area of ​​porous iron to improve electrolysis efficiency. However, this method is essentially still a solid-liquid (solid cathode-molten salt) reaction interface, and its technical limitations are: (1) the electrochemical reaction is still limited to the surface of the solid electrode, and the reduction of titanium ions is limited by their diffusion in the molten salt and adsorption on the surface of the solid cathode, which cannot fundamentally avoid the occurrence of multivalent titanium disproportionation reaction; (2) the metallic titanium obtained by reduction is mainly deposited on the surface or in the pores of the porous iron cathode; (3) as electrolysis proceeds, the deposited titanium layer may block the porous structure, resulting in a decrease in the effective reaction area and difficulty in maintaining the current efficiency.

[0006] Chinese patent CN109913910A discloses a method for preparing ferro-titanium alloy by carbothermic-electrolysis of ilmenite. The method first mixes ilmenite with a carbonaceous reducing agent and adds it to a molten oxide electrolyte. Carbothermic reduction is then carried out at a high temperature of 1540-1800℃ to obtain molten iron. Then, a graphite rod is inserted into the molten iron as a cathode for electrolysis. Titanium is electrochemically deposited on the molten iron cathode to obtain ferro-titanium alloy. The technical essence of this method is a "carbothermic reduction-electrolysis two-step method". Although it ultimately uses a liquid iron cathode, it has the following significant drawbacks: (1) The process is long. An independent, high-temperature carbothermic reduction step must be carried out first to reduce the iron in the ilmenite to molten iron. This step itself is energy-intensive and time-consuming; (2) The carbothermic reduction process will introduce carbon impurities into the system, and the ash from the reducing agent coke or coal may contaminate the electrolyte and the product.

[0007] In summary, existing molten salt electrolysis methods for directly preparing titanium-iron alloys from titanium minerals are either limited by the kinetic bottlenecks and disproportionation reactions of solid cathodes, or rely on pre-processes such as carbothermic reduction, which leads to lengthened processes and the introduction of impurities. Overcoming these shortcomings to achieve a truly short-process, high-efficiency, low-energy-consumption method that effectively suppresses multivalent titanium disproportionation reactions and directly prepares high-purity titanium-iron alloys from complex titanium minerals (such as titanium concentrate and high-titanium slag) remains a pressing technical challenge in this field. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a method for processing vanadium-titanium magnetite to produce titanium-iron alloys, thereby solving the problems of low current efficiency, low production efficiency, and side reactions in molten salt electrolysis of titanium materials, and resolving the current issue of short-process, efficient extraction of metallic titanium from minerals.

[0009] In this invention, high-titanium-content titanium concentrate and high-titanium slag obtained from processing vanadium-titanium magnetite are used as titanium-containing raw materials. The CaO-SiO2-CaF2 slag system, commonly used in metallurgical processes such as steelmaking and welding, is used as the molten salt electrolyte to efficiently dissolve the titanium raw materials. Liquid iron is used as the cathode, and through the electrochemical reaction and mass transfer process at the liquid-liquid interface of the electrode and molten salt, the electrochemically reduced metallic titanium is efficiently reduced and captured. After reduction, the metallic titanium can directly react with the liquid iron to generate FeTi alloy, avoiding the influence of multivalent titanium disproportionation reactions on the molten salt electrolysis process and improving the efficiency of molten salt electrolysis. The process of processing high-titanium-content titanium concentrate and high-titanium slag obtained from vanadium-titanium magnetite is not the focus of this invention and is not described in this patent. Those skilled in the art can process vanadium-titanium magnetite to obtain titanium concentrate and high-titanium slag, etc., as titanium-containing raw materials, based on existing technology.

[0010] The first aspect of this invention provides a method for producing ferrotitanium alloy by processing vanadium-titanium magnetite, comprising the following steps: Titanium-containing raw materials and molten salt are mixed and heated to obtain a molten electrolyte. Liquid iron is used as the cathode and an inert conductive material is used as the anode material. Electrolysis is carried out in the molten electrolyte to obtain a titanium-iron alloy. The molten salt is a ternary system of CaO-SiO2-CaF2.

[0011] In this application, a ternary slag system of CaO, SiO2, and CaF2, commonly used in metallurgical processes and molten welding, is used as the molten salt electrolyte. Its strong dissolving ability for TiO2 is utilized to dissolve high-titanium-content raw materials such as titanium concentrate and high-titanium slag. The temperature is raised above the melting point of pig iron, and liquid iron is used as the cathode. During electrolysis, the denser molten iron is located at the bottom of the crucible, while the less dense molten salt is located above, with a clear interface between the two. This invention transforms the solid-liquid reaction interface of conventional molten salt electrolysis into a liquid-liquid reaction interface, accelerating the electrochemical reaction and mass transfer process. Simultaneously, the alloying process between titanium and iron achieves electrochemical depolarization. The liquid iron effectively captures the formed metallic titanium, effectively reducing the impact of the multivalent titanium disproportionation reaction on the electrochemical reduction process. Ultimately, the goal of efficiently preparing titanium-iron alloys from titanium mineral raw materials is achieved.

[0012] Optionally, the titanium-containing raw material is titanium concentrate or high-titanium slag, wherein the TiO2 content is ≥40wt.%; optionally, the titanium concentrate contains 40wt.%-65wt.% TiO2; and the high-titanium slag contains 75wt.%-95wt.% TiO2.

[0013] Optionally, the mass ratio of titanium-containing raw material to molten salt is 5:100-55:100. Optionally, the mass ratio of titanium-containing raw material to molten salt is 5:100-30:100.

[0014] Optionally, the mass ratio of CaO, SiO2, and CaF2 in the molten salt is (5-35):(7-55):(5-55), and the alkalinity is 0.3-2.5.

[0015] Optionally, the basicity x of the molten salt satisfies the following relationship: when x ≥ 1.0, 0-30 wt.% TiO2 is added to the molten salt; when x < 1.0, 0-15 wt.% TiO2 is added to the molten salt. This application utilizes TiO2 under different basicity conditions... 4+ The stability of TiO2 varies, and its stability can be regulated by controlling the coupling relationship between alkalinity and TiO2. 4+ Inhibit disproportionation reactions.

[0016] Optionally, the basicity x of the molten salt satisfies the following relationship: when x ≥ 1.0, 5-20 wt.% TiO2 is added to the molten salt; when x < 1.0, 5-10 wt.% TiO2 is added to the molten salt.

[0017] Optionally, the electrolysis temperature is 1370-1600℃, and the electrolysis is performed using constant current or constant voltage methods, with a constant current density of 0.1-10 A·cm⁻¹. -2 The constant voltage is 1.5-5V.

[0018] Optionally, the electrolysis temperature is 1400-1550°C, and the electrolysis time is 4-48 hours. Preferably, the electrolysis time is 8-24 hours.

[0019] Optionally, the molten salt contains at least one oxide selected from MgO, Al2O3, or Y2O3, accounting for 0.5-5 wt.% of the total mass of the molten salt. For example, the mass of the added oxide can be any point value or a range between any two points from 0.5 wt.%, 1 wt.%, 1.5 wt.%, 2 wt.%, 2.5 wt.%, 3 wt.%, 3.5 wt.%, 4 wt.%, 4.5 wt.%, or 5 wt.%.

[0020] Optionally, the electrolysis uses pulsed current with the following pulse parameters: on-time 10-200ms, off-time 5-100ms, and duty cycle 50%-90%.

[0021] Optionally, the anode material is a graphite rod; optionally, the graphite rod is high-purity graphite with a diameter of 3-100 mm, preferably 6-15 mm, and is immersed in the molten electrolyte to a depth of 1-30 cm.

[0022] The cathode material is cast iron or steel, wherein the iron content of the cast iron or steel is 90 wt.%-99 wt.%, and the carbon content is 0 wt.%-6 wt.%. Both the anode and cathode leads are made of Ti, W, or Mo, and a boron nitride, aluminum oxide, or magnesium oxide insulating sleeve is provided between the cathode lead and the molten electrolyte. Preferably, a boron nitride insulating sleeve is provided between the cathode lead and the molten electrolyte.

[0023] Optionally, the viscosity of the molten electrolyte is ≤2 Pa·s, and the conductivity is ≥0.8 S·cm. -1 This ensures the high solubility and ionic conductivity of TiO2, further guaranteeing the smooth progress of liquid-liquid interface electrolysis.

[0024] Specifically, the method for processing vanadium-titanium magnetite to produce ferrotitanium alloy includes the following steps: Step 1: Molten salt dehydration treatment Molten salt and titanium-containing raw materials are mixed in a certain proportion, vacuum dried in an inert atmosphere and at a certain temperature, and then cooled to room temperature in the furnace to obtain a dehydrated mixture. Step 2: Electrode treatment The anode material and electrode lead material are polished and cleaned, then connected to the electrode leads to form the electrode. Pig iron or steel is cleaned and dried to serve as the cathode material.

[0025] Step 3: Electrolysis reaction, (1) Place the cathode material at the bottom of the crucible, place the dehydrated mixture in the crucible and above the cathode material, place it in a sealed reactor, introduce an inert atmosphere for protection, gradually raise the temperature to the reaction temperature, keep it at the temperature for a period of time, dissolve the reactants, and obtain molten electrolyte and liquid iron cathode. (2) An anode and a cathode lead insulated from the molten electrolyte are placed in the electrolyte, and a constant current or constant voltage is applied for electrolysis to obtain a titanium-iron alloy. (Reference) Figure 1 As shown, Figure 1 An exemplary embodiment of the apparatus structure used in the molten salt electrolysis based on liquid iron cathode described in this invention is shown.

[0026] Step 4: Post-processing After electrolysis, the crucible is cooled, and the titanium-iron alloy at the bottom of the crucible is removed and ultrasonically cleaned to obtain the titanium-iron alloy product.

[0027] Optionally, in step 1, the vacuum drying process is as follows: drying temperature is 200-450℃, drying time is 8-48h, and heating rate is 2-10℃ / min. Preferably, the temperature is 250-350℃, drying time is 12-24h, and heating rate is 2-5℃ / min.

[0028] Optionally, in step 1, the molten salt and titanium raw material can be mixed by manual grinding, mechanical stirring, or mechanical ball milling. Mechanical ball milling is preferred.

[0029] Optionally, in step 3(1), the crucible may be a boron nitride crucible, a graphite crucible, a magnesium oxide crucible, an aluminum oxide crucible, a graphite clay crucible, or a clay crucible. Preferably, it is a boron nitride or magnesium oxide crucible.

[0030] Optionally, in step 3(1), the mass ratio of the cathode material to the dehydration mixture is 1:3-1:30. Preferably, it is 1:5-1:15.

[0031] Optionally, in step 3(1), the inert atmosphere is argon or nitrogen.

[0032] Optionally, in step 3(1), the reaction temperature is 1370-1600℃ and the heating rate is 3-10℃ / min. Preferably, it is 1400-1550℃ and the heating rate is 5-8℃ / min.

[0033] Optionally, in step 3(1), the heat preservation period is 15-240 minutes. Preferably, it is 30-120 minutes.

[0034] Optionally, in step 3(1), the heating device for the reactor is preferably a molybdenum disilicide rod heating element resistance furnace.

[0035] Optionally, in step 4, ultrasonic cleaning is performed, specifically by first cleaning with hydrochloric acid and then rinsing with water. The ultrasonic frequency is 10-30 kHz. The pH of the water is 5-7, and the hydrochloric acid is a hydrochloric acid solution with a molar concentration of 0.5-2 mol / L.

[0036] Compared with the prior art, the present invention achieves at least one of the following beneficial effects: (1) This invention has the advantages of being simple, efficient, short process and low cost, and realizes the efficient and short process of preparing titanium-iron alloy from titanium mineral raw materials, providing a theoretical and technical basis for the efficient, low-cost and green preparation of metallic titanium.

[0037] (2) This invention transforms the solid-liquid (solid cathode-molten salt) reaction interface of conventional molten salt electrolysis into a liquid-liquid (liquid iron cathode-molten salt) reaction interface. Because liquid iron has a high density and is immiscible with molten salt, the two form a stable stratification. The electrochemical reaction takes place at the liquid-liquid interface, eliminating the need for titanium ions to diffuse in the solid phase, thus increasing the mass transfer rate by several to tens of times. This fundamentally solves the problems of slow oxygen ion diffusion and limited reaction interface in solid cathodes.

[0038] (3) In the solid cathode electrolysis of the present invention, the reduced metallic titanium is enriched on the cathode surface, and Ti is prone to occur. 2+ / Ti 3+The disproportionation reaction in titanium leads to low current efficiency (typically <50%). In this invention, the reduced titanium atoms are immediately diluted by a large number of iron atoms to form an alloy. The extremely low activity of titanium thermodynamically inhibits the disproportionation reaction. Simultaneously, the liquid iron cathode efficiently captures the reduction products, preventing them from returning to the molten salt. The measured current efficiency is no less than 75%, significantly superior to solid cathode technology.

[0039] (4) This invention directly uses titanium concentrate (TiO2≥40%) or high-titanium slag (TiO2≥75%) as the titanium source, and utilizes the strong dissolving ability of CaO-SiO2-CaF2 molten salt to titanium minerals to obtain titanium-iron alloys in one step through electrolysis. This eliminates the need for chlorination, pickling, and pre-reduction steps, shortening the process flow by about 1 / 3. It also eliminates chlorine and waste acid emissions, making it environmentally friendly. Furthermore, the molten salt has a viscosity ≤2 Pa·s and an electrical conductivity ≥0.8 S·cm in the temperature range of 1370-1600℃. -1 It has both good solubility and ionic conductivity, which fully meets the requirements of liquid-liquid interface electrolysis.

[0040] (5) This invention can change the Ca content by adding 0.5-5 wt.% of MgO, Al2O3 or Y2O3 to the molten salt. 2+ The coordination state in molten salt or the formation of an in-situ barrier layer on the cathode surface effectively suppresses Ca. 2+ The co-deposition significantly improves the purity of titanium-iron alloys. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the apparatus used in the molten salt electrolysis based on liquid iron cathode described in this invention is shown. Figure 2 The XRD pattern of the iron-titanium alloy prepared in Example 1 of the present invention is shown.

[0042] in: 1-Reactor; 2-Crucible; 3-Graphite rod; 4-Anode lead; 5-Cathode lead; 6-Insulating sleeve; 7-Inlet pipe; 8-Outlet pipe; 9-Sealing flange; 10-Sealing ring. Detailed Implementation

[0043] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0044] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0045] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0046] In the embodiments of this invention, CaO, SiO2, and CaF2 are commercially available analytical grade reagents with a purity of 99%; and the proportions of the residue used on-site in industrial settings are adjusted using analytical grade reagents. The iron used in the embodiments of the present invention is pig iron, scrap stainless steel, and molten iron and steel obtained on the production site.

[0047] Example 1 In an exemplary embodiment of the present invention, a method for processing vanadium-titanium magnetite to produce ferrotitanium alloy includes the following steps: Step 1: Molten salt dehydration treatment Molten salt CaO-SiO2-CaF2 (CaO, SiO2, CaF2 mass ratio of 20:30:50, basicity of 0.67) and titanium concentrate (TiO2 50wt.%) were mixed at a mass ratio of 15:100 and vacuum dried at 300℃ under nitrogen atmosphere for 15 hours with a heating rate of 3℃ / min. The mixture was then cooled to room temperature in the furnace to obtain a dehydrated mixture. Step 2: Electrode treatment A graphite rod (10mm in diameter and 80mm in length) for the anode material and electrode lead material W were polished with 400#, 1000#, and 2000# sandpaper, cleaned with ethanol, and dried in a drying oven at 80°C for 8 hours. The anode material was then connected to the electrode lead to form the electrode. Pig iron (99wt.%) was cleaned and dried to serve as the cathode material. A graphite rod (5mm in diameter and 30mm in length) was polished with 400#, 1000#, and 2000# sandpaper, cleaned with ethanol, and dried in a drying oven at 80°C for 8 hours. The graphite rod was then connected to the electrode wire and cathode lead, with the electrode lead protected by a boron nitride tube.

[0048] Step 3: Electrolysis reaction, (1) Place the pig iron cathode material at the bottom of the boron nitride crucible, place the dehydration mixture in the crucible and above the cathode material, the mass ratio of the cathode material to the dehydration mixture is 1:15, place it in a sealed reactor, introduce an inert atmosphere of nitrogen for protection, gradually raise the temperature to the reaction temperature of 1450℃ at a rate of 5℃ / min, hold for 50min, dissolve the reactants, and obtain molten electrolyte and liquid iron cathode; (2) A graphite rod of anode and a cathode lead W that is insulated from the molten electrolyte are placed in the molten electrolyte. Boron nitride tubes are used to insulate the cathode lead from the molten electrolyte. Constant voltage electrolysis is performed with a constant voltage of 3V for 12 hours to obtain titanium-iron alloy.

[0049] Step 4: Post-processing After electrolysis, the crucible is cooled, and the titanium-iron alloy at the bottom of the crucible is removed and ultrasonically cleaned. First, it is cleaned with 1 mol / L hydrochloric acid, and then with water with a pH of 6. The ultrasonic frequency is 20 kHz to obtain the titanium-iron alloy product.

[0050] Example 2 In an exemplary embodiment of the present invention, a method for processing vanadium-titanium magnetite to produce ferrotitanium alloy includes the following steps: Step 1: Molten salt dehydration treatment Molten salt CaO-SiO2-CaF2 (CaO, SiO2, CaF2 mass ratio of 15:35:50, basicity of 0.43) and titanium concentrate (TiO2 55wt.%) were mixed at a mass ratio of 20:100, and vacuum dried at 200℃ under nitrogen atmosphere for 15h with a heating rate of 3℃ / min. The mixture was then cooled to room temperature in the furnace to obtain a dehydrated mixture. Step 2: Electrode treatment The anode material (graphite rod) and electrode lead material (W) are ground, cleaned, and then connected to the electrode leads to form the electrode. The graphite rod has a diameter of 10 mm. Pig iron (99 wt.%) is cleaned, dried, and used as the cathode material.

[0051] Step 3: Electrolysis reaction, (1) Place the cathode material pig iron at the bottom of the boron nitride crucible, place the dehydration mixture in the crucible and above the cathode material, the mass ratio of the cathode material to the dehydration mixture is 1:15, place it in a sealed reactor, introduce an inert atmosphere of nitrogen for protection, gradually raise the temperature to the reaction temperature of 1420℃ at a rate of 5℃ / min, hold for 50min, dissolve the reactants, and obtain molten electrolyte and liquid iron cathode; (2) A graphite anode rod and a cathode lead W that is insulated from the molten electrolyte are placed in the molten electrolyte. Boron nitride tubes are used to insulate the cathode lead from the molten electrolyte. Constant voltage electrolysis is performed with a constant voltage of 2.8V for 16 hours to obtain a titanium-iron alloy.

[0052] Step 4: Post-processing After electrolysis, the crucible is cooled, and the titanium-iron alloy at the bottom of the crucible is removed and ultrasonically cleaned. First, it is cleaned with 1 mol / L hydrochloric acid, and then with water with a pH of 6. The ultrasonic frequency is 10 kHz to obtain the titanium-iron alloy product.

[0053] Example 3 In an exemplary embodiment of the present invention, a method for processing vanadium-titanium magnetite to produce ferrotitanium alloy includes the following steps: Step 1: Molten salt dehydration treatment Molten salt CaO-SiO2-CaF2 (CaO, SiO2, CaF2 mass ratio of 25:25:50, basicity of 1.0) and high titanium slag (TiO2 90wt.%) were mixed at a mass ratio of 10:100 and vacuum dried at 350℃ under nitrogen atmosphere for 20 h with a heating rate of 5℃ / min. The mixture was then cooled to room temperature in the furnace to obtain a dehydrated mixture. 2 wt.% Al2O3 was also added to the molten salt.

[0054] Step 2: Electrode treatment The anode material (graphite rod) and electrode lead material (W) are ground, cleaned, and then connected to the electrode leads to form the electrode. The graphite rod has a diameter of 10 mm. Pig iron (99 wt.%) is cleaned, dried, and used as the cathode material.

[0055] Step 3: Electrolysis reaction, (1) Place the pig iron cathode material at the bottom of the boron nitride crucible, place the dehydration mixture in the crucible and above the cathode material, the mass ratio of the cathode material to the dehydration mixture is 1:15, place it in a sealed reactor, introduce an inert atmosphere of nitrogen for protection, gradually raise the temperature to the reaction temperature of 1500℃ at a rate of 6℃ / min, hold for 80min, dissolve the reactants, and obtain molten electrolyte and liquid iron cathode; (2) An anode graphite rod and a cathode lead W, which is insulated from the molten electrolyte, are placed in the molten electrolyte. Boron nitride tubes are used to insulate the cathode lead from the molten electrolyte. Constant current electrolysis is performed with a constant current of 1.5 A·cm⁻¹. -2 Electrolysis for 8 hours yields titanium-iron alloy.

[0056] Step 4: Post-processing After electrolysis, the crucible is cooled, and the titanium-iron alloy at the bottom of the crucible is removed and ultrasonically cleaned. First, it is cleaned with 1 mol / L hydrochloric acid, and then with water with a pH of 6. The ultrasonic frequency is 10 kHz to obtain the titanium-iron alloy product.

[0057] Example 4 In an exemplary embodiment of the present invention, a method for processing vanadium-titanium magnetite to produce ferrotitanium alloy includes the following steps: Step 1: Molten salt dehydration treatment Molten salt CaO-SiO2-CaF2 (CaO, SiO2, CaF2 mass ratio of 15:35:50, basicity of 0.43) and high titanium slag (TiO2 55wt.%) were mixed at a mass ratio of 20:100 and vacuum dried at 200℃ under nitrogen atmosphere for 24 hours at a heating rate of 5℃ / min. The mixture was then cooled to room temperature in the furnace to obtain a dehydrated mixture. 1.5wt.% MgO was also added to the molten salt.

[0058] Step 2: Electrode treatment The anode material (graphite rod) and electrode lead material (W) are ground, cleaned, and then connected to the electrode leads to form the electrode. The graphite rod has a diameter of 10 mm. Steel (97 wt.% iron content) is cleaned, dried, and used as the cathode material.

[0059] Step 3: Electrolysis reaction, (1) Place the cathode material steel at the bottom of the boron nitride crucible, place the dehydration mixture in the crucible and above the cathode material, the mass ratio of the cathode material to the dehydration mixture is 1:15, place it in a sealed reactor, introduce an inert atmosphere of nitrogen for protection, gradually raise the temperature to the reaction temperature of 1420℃ at a rate of 6℃ / min, hold for 80min, dissolve the reactants, and obtain molten electrolyte and liquid iron cathode; (2) A graphite anode rod and a cathode lead W, which are insulated from the molten electrolyte, are placed in the molten electrolyte. Boron nitride tubes are used to insulate the cathode lead from the molten electrolyte. Constant voltage electrolysis is performed with a constant voltage of 2.0V for 8 hours to obtain a titanium-iron alloy.

[0060] Step 4: Post-processing After electrolysis, the crucible is cooled, and the titanium-iron alloy at the bottom of the crucible is removed and ultrasonically cleaned. First, it is cleaned with 1 mol / L hydrochloric acid, and then with water with a pH of 6. The ultrasonic frequency is 10 kHz to obtain the titanium-iron alloy product.

[0061] Example 5 In an exemplary embodiment of the present invention, a method for processing vanadium-titanium magnetite to produce ferrotitanium alloy includes the following steps: Step 1: Molten salt dehydration treatment Molten salt CaO-SiO2-CaF2 (CaO, SiO2, CaF2 mass ratio of 30:20:50, basicity of 1.5) and high titanium slag (TiO2 85wt.%) were mixed at a mass ratio of 25:100. The mixture was vacuum dried at 300℃ under an argon atmosphere for 24 hours at a heating rate of 5℃ / min. The mixture was then cooled to room temperature in the furnace to obtain a dehydrated mixture. Y2O3, accounting for 0.5wt.% of the total mass of the molten salt, was also added to the molten salt.

[0062] Step 2: Electrode treatment The anode material (graphite rod) and electrode lead material (Mo) are ground, cleaned, and then connected to the electrode leads to form the electrode. The graphite rod has a diameter of 10 mm. Steel (99 wt.% iron content) is cleaned, dried, and used as the cathode material.

[0063] Step 3: Electrolysis reaction, (1) Place the cathode material steel at the bottom of the boron nitride crucible, place the dehydration mixture in the crucible and above the cathode material, the mass ratio of the cathode material to the dehydration mixture is 1:15, place it in a sealed reactor, introduce an inert atmosphere of nitrogen for protection, gradually raise the temperature to the reaction temperature of 1550℃ at a rate of 6℃ / min, hold for 80min, dissolve the reactants, and obtain molten electrolyte and liquid iron cathode; (2) A graphite rod at the anode and a cathode lead Mo, which is insulated from the molten electrolyte, are placed in the molten electrolyte. Boron nitride tubes are used to insulate the cathode lead from the molten electrolyte. Constant voltage electrolysis is performed at 2.0V for 8 hours to obtain a titanium-iron alloy.

[0064] Step 4: Post-processing After electrolysis, the crucible is cooled, and the titanium-iron alloy at the bottom of the crucible is removed and ultrasonically cleaned. First, it is cleaned with 1 mol / L hydrochloric acid, and then with water with a pH of 6. The ultrasonic frequency is 10 kHz to obtain the titanium-iron alloy product.

[0065] Example 6 The main difference from Example 5 is that the electrolysis uses a pulsed current with the following parameters: on-time 50ms, off-time 25ms, duty cycle 66.7%, and average current density 2 A·cm. -2 Electrolysis for 10 hours.

[0066] Example 7 The main difference from Example 5 is that TiO2, accounting for 10 wt.% of the total mass of the molten salt, is added to the molten salt.

[0067] Example 8 The main difference from Example 5 is that TiO2, accounting for 40 wt.% of the total mass of the molten salt, is added to the molten salt.

[0068] Example 9 The main difference from Example 4 is that TiO2, accounting for 5 wt.% of the total mass of the molten salt, is added to the molten salt.

[0069] Example 10 The main difference from Example 4 is that TiO2, accounting for 20 wt.% of the total mass of the molten salt, is added to the molten salt.

[0070] Example 11 The main difference from Example 5 is that Y2O3, accounting for 10 wt.% of the total mass of the molten salt, is added to the molten salt.

[0071] Comparative Example 1 The main difference from Example 1 is that solid iron is used as the cathode.

[0072] Comparative Example 2 The main difference from Example 1 is that the molten salt consists only of CaO and SiO2 in a mass ratio of 20:30, and does not contain CaF2. Comparative Example 3 The main difference from Example 1 is that SiO2 was not added.

[0073] Test case The molten electrolyte was subjected to performance tests. The viscosity and conductivity data below were measured at the electrolysis temperature of their respective embodiments. The test results are shown in Table 1.

[0074] Table 1

[0075] Referring to Table 1, the molten electrolyte of this application has a viscosity of <2.0 Pa•s and a conductivity of not less than 0.8 S•cm. -1 It exhibits low viscosity and high conductivity, ensuring stable electrolysis. In contrast, Comparative Example 2, lacking CaF2, has a molten salt viscosity > 6 Pa•s and conductivity < 0.2 S•cm. -1 The first example could not be electrolyzed normally; although the second example had lower viscosity and higher conductivity, the lack of SiO2 resulted in poor stability of titanium ions and poor electrolysis performance.

[0076] The titanium-iron alloys prepared in the above examples and comparative examples were subjected to performance tests, and the test results are shown in Table 2.

[0077] Among them, the extreme relative value of titanium content is: the Ti content is measured at three points on the top, middle and bottom of the alloy block, and the value is calculated as (maximum value - minimum value) / average value × 100%.

[0078] Table 2

[0079] Referring to Table 2, the current efficiency of this application is not less than 75% and can reach up to 92%, which is much higher than that of the solid cathode in Comparative Example 1. This indicates that the liquid iron cathode combined with the liquid-liquid interface can effectively suppress the disproportionation reaction of multivalent titanium and significantly improve the electrolysis efficiency. The Ca impurity content is not higher than 95 ppm. After adding MgO, Al2O3 or Y2O3 in the examples, the Ca impurity content in the alloy was significantly reduced to 4-61 ppm, with Y2O3 showing the best effect. The O impurity content is not higher than 0.35 wt.%, and the relative deviation of titanium content at multiple points is not higher than 4.3%, indicating good compositional uniformity.

[0080] Based on the above data, this invention achieves a direct, efficient, and short-process preparation of high-purity, uniformly composed titanium-iron alloys from titanium concentrate / high-titanium slag, with significantly better technical results than existing technologies.

[0081] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for processing vanadium-titanium magnetite to produce titanium-iron alloy, characterized in that, Includes the following steps: Titanium-containing raw materials and molten salt are mixed and heated to obtain a molten electrolyte. Liquid iron is used as the cathode and an inert conductive material is used as the anode material. Electrolysis is carried out in the molten electrolyte to obtain a titanium-iron alloy. The molten salt is a ternary system of CaO-SiO2-CaF2.

2. The method for producing titanium-iron alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The titanium-containing raw materials are titanium concentrate or high-titanium slag, wherein the TiO2 content is ≥40wt.%; further, the titanium concentrate contains 40wt.%-65wt.% TiO2; and the high-titanium slag contains 75wt.%-95wt.% TiO2.

3. The method for producing titanium-iron alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The mass ratio of titanium-containing raw materials to molten salt is 5:100-55:

100.

4. The method for producing ferrotitanium alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The mass ratio of CaO, SiO2, and CaF2 in the molten salt is (5-35):(7-55):(5-55), and the alkalinity is 0.3-2.

5.

5. The method for producing ferrotitanium alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The electrolysis temperature is 1370-1600℃, and electrolysis is performed using constant current or constant voltage methods. The constant current density is 0.1-10 A•cm. -2 The constant voltage is 1.5-5V.

6. The method for producing titanium-iron alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The molten salt contains at least one oxide selected from MgO, Al2O3, or Y2O3, accounting for 0.5-5 wt.% of the total mass of the molten salt.

7. The method for producing ferrotitanium alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The electrolysis uses pulsed current with the following pulse parameters: on-time 10-200ms, off-time 5-100ms, and duty cycle 50%-90%.

8. The method for producing ferrotitanium alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The anode material is a graphite rod; The cathode material is cast iron or steel, wherein the iron content of the cast iron or steel is 90 wt.%-99 wt.%, and the carbon content is 0 wt.%-6 wt.%. Both the anode and cathode leads are made of Ti, W, or Mo, and the cathode lead is provided with a boron nitride, aluminum oxide, or magnesium oxide insulating sleeve between it and the molten electrolyte.

9. The method for producing titanium-iron alloy from vanadium-titanium magnetite according to claim 1, characterized in that, The molten electrolyte has a viscosity ≤ 2 Pa·s and a conductivity ≥ 0.8 S·cm. -1 .

10. A titanium-iron alloy product prepared by the method according to any one of claims 1-9, characterized in that, The titanium content of the titanium-iron alloy product is 10-70 wt.%, the Ca impurity content in the titanium-iron alloy product is ≤0.1 wt.%, the O impurity content is ≤0.5 wt.%, and the extreme relative value of titanium content at different sampling points does not exceed 5%.

Images