A system and method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end titanium sponge from ilmenite

Abstract

The present application belongs to the field of energy and metallurgy. Specifically, the present application discloses a system and method for simultaneously producing low-carbon pure iron, titanium dioxide and high-end titanium sponge from ilmenite. The ilmenite is directly acidolysed by an acidolysis separation process to obtain titanyl sulfate solution and iron salt crystals. A purified iron salt solution is obtained by a dissolution purification process, and the resource utilization of the dissolved residue / purified residue and the cyclic utilization of sulfur are realized. The preparation of pure iron is realized by a cell iron smelting process and a solution depletion process, and the recycling of the system sulfuric acid cycle and hydrogen product and oxygen product is realized. The preparation of titanium dioxide is realized by a titanium dioxide process using fine particle fluidized calcination technology. The high-end titanium sponge is obtained by a high-end titanium sponge process using coarse particle fluidized calcination. The present application is suitable for large-scale continuous production of low-carbon pure iron, titanium dioxide and high-end titanium sponge from ilmenite, and has the advantages of high efficiency, low energy consumption, no pollution and good economy.

Description

Technical Field

[0001] This invention belongs to the fields of energy and metallurgy, and specifically relates to a system and method for simultaneously producing low-carbon pure iron, titanium dioxide and high-end sponge titanium from ilmenite. Background Technology

[0002] In 2021, my country's crude steel production was approximately 1 billion tons, emitting about 1.8 billion tons of CO2, accounting for about 16% of the country's total emissions. my country's steel industry primarily utilizes a long process, such as blast furnace-converter, accounting for as much as 90% of production. Blast furnace ironmaking is the main source of CO2 emissions, accounting for about 70% of the entire process. Blast furnace ironmaking uses coke as a reducing agent to remove oxygen from iron ore, producing molten iron, but releasing large amounts of CO2. Against the backdrop of "carbon peaking" and "carbon neutrality," the steel industry urgently needs to develop transformative low-carbon ironmaking technologies.

[0003] Currently developed ultra-low carbon ironmaking technologies mainly focus on replacing coke. These include hydrogen reduction as a substitute for carbon reduction and electroreduction as a substitute for carbon reduction.

[0004] The "hydrogen reduction" route, namely, hydrogen production through water electrolysis and hydrogen reduction of iron, is described in patent CN112159880B. This method and apparatus for hydrogen iron smelting involves using microwave irradiation to smelt iron ore in a hydrogen or hydrogen-rich gas atmosphere to obtain directly reduced iron. This solves the problem of significant carbon dioxide emissions still occurring when using hydrogen-rich gas to reduce iron oxides in existing hydrogen iron smelting processes. Patent application CN102586527A discloses a new hydrogen-carbon molten reduction iron smelting process. The heat required for the entire process is provided by the combustion of oxygen-coal and the secondary combustion of reducing gases. Compared with existing processes, this process reduces CO2 emissions by approximately 10%. Patent application CN105886688A discloses a green circular production system where hydrogen replaces carbon in reducing iron ore to elemental iron during metal smelting. No CO2 is produced in the process; the steam generated during smelting generates electricity, and the H2 produced from water electrolysis is recycled. However, current industrial-scale water electrolysis for hydrogen production primarily uses alkaline aqueous solutions, with an energy efficiency of around 60%, and the efficiency of hydrogen production is also relatively low. In the process of hydrogen reducing iron, due to limited thermodynamic equilibrium, the single-cycle conversion rate is low, requiring multiple cycles and increasing energy consumption. Simultaneously, the thermal effect of hydrogen reducing iron is poor, requiring a significant amount of additional thermal energy. Overall, "hydrogen metallurgy" essentially consumes green electrical energy; it is electrometallurgy. Developing a step-by-step electrochemical reduction of iron is also of great significance.

[0005] Iron ore can be decomposed into metallic iron and release oxygen under electrochemical action. This process is generally carried out in three typical systems: a high-temperature molten salt / molten iron oxide system, an alkaline system, and an acidic system. The high-temperature molten salt / molten iron oxide system is described in patent application CN114232033A, which discloses a method for preparing high-purity iron by high-temperature molten salt electroreduction using CaCl2. Fe2O3 In a CaO molten salt system, high-purity iron (99.94%) can be obtained through molten salt electroreduction at a certain current density and an inert argon atmosphere at 850℃. Patent CN101906646B discloses a method for producing metallic iron from iron ore via molten salt electrolysis, using a Fe2O3-Al2O3-SiO2 molten salt system, and obtaining metallic iron through molten salt electroreduction at a certain current density and electrolysis temperature (1580-1620℃). Patent CN109477232B discloses a method for preparing iron by reducing molten oxides using electrolytic deposition, using a Na2O2-B2O3-Fe2O3 molten salt system, and obtaining metallic iron (97%) through molten salt electroreduction at a certain voltage (1.5V / 2.5V) and electrolysis temperature (1000℃). Currently, the main challenges of high-temperature molten salt / molten iron oxide systems are the development of economical inert anode materials, suitable electrolyte systems, and the purification of raw materials.

[0006] An alkaline solution electroreduction technique for producing iron. Allanore A et al. (DOI: 10.1149 / 1.2790285) experimentally demonstrated that electrolysis of suspended iron oxide particles in a sodium hydroxide solution (50% mass concentration, 110℃) (iron ion concentration 2.6 × 10⁻⁶) yields iron. -3The invention mentions the possibility of iron formation (M), but also notes the very low solubility of hematite in this system, leading to extremely low reduction efficiency. Patent CN101696510B discloses a method and apparatus for preparing high-purity iron powder through electrolytic deoxygenation, involving an electrochemical method for obtaining high-purity iron from solid iron oxide. Solid iron oxide is a sintered body or ore composed of single or mixed Fe2O3, Fe3O4, and FeO. The anode and cathode are located at opposite ends of an electrolytic cell. The electrolytic cell contains an ion-conducting membrane and a high-temperature hydroxide solution (sodium hydroxide or potassium hydroxide, at 700-800℃). A preset voltage is applied between the electrodes to drive oxygen ions to diffuse from the iron oxide in the cathode basket to the anode, where high-purity iron can be obtained. However, in this patent, the anode must be a solid material with strong alkali resistance, corrosion resistance, and good conductivity, and the solid oxygen ion-conducting membrane must also possess alkali resistance and corrosion resistance, thus resulting in high costs. In addition, to prevent impurities in solid iron oxide from dissolving in high-temperature alkaline solutions and adversely affecting electrolyte performance, iron oxide needs to undergo impurity removal pretreatment, which will lead to a significant increase in economic and environmental costs.

[0007] Acidic Solution Electroreduction Technology for Iron Production. Researchers have conducted extensive work on the electroreduction of iron from acidic iron-containing solutions, primarily aiming to prepare high-purity metallic iron and pure iron powder. The most common electrolyte solutions used in this process are ferrous chloride and ferrous sulfate. Acidic FeCl2 solution: Patent application CN107955952A discloses a method for producing high-purity iron powder from iron slag. This involves leaching (leaching solution composition: 15-19 parts sodium hydroxide, 5-9 parts sodium methacrylate, 260-300 parts water) to remove inorganic components such as silica from the iron slag, increasing the iron particle content in the filter residue. An electrolyte solution containing 6-9 parts (15% by volume) of hydrochloric acid, 10-14 parts (magnesium sulfate), and 900-1000 parts (water) is then added for electrolysis. Finally, the surface of the iron powder is cleaned using an 18-22% (w / w) ethylenediaminetetraacetic acid solution to obtain high-purity iron powder. The patented method consumes large amounts of sodium hydroxide and hydrochloric acid during leaching and electrolysis. Furthermore, due to impurities and concentration, these leachates and electrolytes cannot be recycled, making subsequent processing difficult. Patent CN101517129B discloses an electrochemical method for recovering iron and chlorine from an iron-rich metal chloride solution, with a cathode electrolyte pH of 0.9-1.1, an electroreduction temperature of 80-85 ℃, and a cathode current density of 200-500 A / m. 2 The current efficiency is 96.4%-97.9%, and the purity of iron prepared by electroreduction is 99.99%. This patent has high requirements for the control of impurity content and pH in the solution. The ferric chloride solution needs to be adjusted to a relatively low pH value to prevent the pH value on the cathode surface from rising to a level higher than the precipitation pH value of other impurities, causing co-precipitation. However, it cannot be too low to prevent the release of hydrogen gas as a byproduct.

[0008] Acidic FeSO4 electrolyte solution. Patent application CN113481540A discloses a method for preparing high-purity iron, using a soluble anode, an electrolyte mainly containing FeSO4 and a small amount of stabilizer, and a cathode current density of 100. 230 A / m 2 The electrolyte pH is 1.00-4.00, the electrolyte temperature is 20-100 ℃, the purity of the iron prepared by electrolysis is 99.90%~99.99%, and the deposition thickness is 20 μm~3 cm. This patent uses a sulfuric acid system, and the soluble anode is industrial pure iron, low carbon steel, etc., so the purity of the electrolyte solution is high. However, if the purity of the electrolyte decreases, it will lead to a series of problems such as more side reactions, reduced current efficiency, and contamination by impurities. Patent CN102084034B discloses an electrochemical method for recovering metallic iron or iron-rich alloys, oxygen and sulfuric acid from iron-rich metal sulfate waste (byproduct of the ilmenite sulfate process). The electrolyte is an iron-rich metal sulfate solution, the electrolyte pH is 1.4-3.5, the electrolyte temperature is 25-60 ℃, and the cathode current density used is 300 1000 A / m 2 The purity of iron produced by electrolysis can reach 99.99%, with a current efficiency of 95%-98%. In this patent, the iron-rich metal sulfate solution must undergo pretreatment (such as pH adjustment) before electroreduction, and the acidic insoluble solids produced in this process are also difficult to handle. Furthermore, E. Mostad et al. (DOI:10.1016 / j.hydromet.2007.07.014) mentioned that a Norwegian smelter conducted a semi-industrial electroreduction experiment between 1947 and 1957 using pyrite (FeS2) as raw material in a pilot plant, conducting electroreduction experiments on FeSO4 solutions produced from calcination and sulfuric acid leaching processes, ultimately obtaining high-purity metallic iron. This process was the first to use iron ore (pyrite) as raw material to electroreduce metallic iron, producing a total of 1.5 × 10⁻⁶ tons of iron between 1955 and 1957. 5A study by WD Badenhorst et al. (DOI: 10.3390 / membranes9110137) found that using a novel BM-5 AEM anion exchange membrane could achieve a current efficiency of 95% in iron electrolysis with an energy consumption of 3.53 kWh / kg iron, which is superior to the existing Pyror process and also shows better stability and lower energy consumption than commercially available AEM membranes. The study also found that when the iron concentration in the solution is below 5 g / L, cathode side reactions lead to a decrease in process efficiency. However, these studies mainly use pyrite or ferrous sulfate as raw materials, with limited research on the broader applications of hematite or magnetite. Patent applications WO2022204379A1 and WO2022197954A1 disclose a method for producing pure iron from iron ore and removing impurities from the solution. This method first involves thermally reducing one or more non-magnetic iron oxide components in the iron ore to form magnetite in the presence of a reducing agent. Then, the magnetite is dissolved in acid to form an acidic iron salt solution. Undissolved impurities are separated and processed. Subsequently, the acidic iron salt is electrolyzed to obtain high-purity iron, and the remaining solution is returned to the acidolysis tank for recycling. However, the reducing agent mentioned in these patents is mainly hydrogen, which is generated through a chemical reaction between iron metal and acid. This method requires the addition of iron metal, increasing costs. Furthermore, this exothermic reaction easily generates a large amount of hydrogen and heat instantaneously, significantly impacting equipment and safety. Furthermore, this method reduces iron ore to magnetite through thermal reduction, specifically by lowering the valence state of some iron in the ore to promote dissolution. This is primarily because a higher degree of iron reduction in the ore results in a higher leaching rate (DOI: 10.3321 / j.issn:1005-3026.2008.12.017). However, the patent does not mention how to achieve efficient iron ore reduction, nor does it address the failure to recover and utilize the heat generated during this process. Additionally, the acid used to dissolve magnetite in this method is highly acidic, while the acidity of the solution recycled back to the acidolysis tank after electrolysis is relatively low, potentially leading to an acidity mismatch that hinders magnetite dissolution. Patent applications WO2022204387A1, WO2022204391A1, and WO2022204394A1 disclose a method for dissolving, converting, and systematically utilizing iron ore. This method involves dissolving iron-containing ore into an acidic iron salt solution and then reacting Fe in a first electrolytic cell. 3+ Reduction to form Fe 2+ The Fe that will be formed subsequently 2+The iron is transferred from the first electrolytic cell to the second electrolytic cell and reduced to high-purity iron, with the remaining solution returned to the dissolving tank. In this method, the first and second electrolytic cells employ proton exchange membranes (PEM) and anion exchange membranes (AEM), respectively. The use of two different types of ion-exchange membranes increases the variety of membranes used in the electrolytic cells, thus increasing operating costs. Furthermore, the patent mentions that the volume of solution entering the cathode chamber in the second electrolytic cell is smaller than the volume entering the anode chamber, increasing process complexity and potentially reducing iron utilization efficiency. Since the patent also uses hydrochloric acid to dissolve magnetite, the introduction of chloride ions can lead to a competing reaction at the anode, increasing the risk of chlorine gas evolution and potentially exacerbating wear on the ion-exchange membrane, further increasing costs. Additionally, the patent does not address the recovery and reuse of the evolved oxygen.

[0009] Ilmenite is the main ore for titanium extraction, accounting for about 90% of titanium ore reserves, and is also a major raw material for iron product preparation. my country's titanium resources are mainly concentrated in the Panzhihua-Xichang area, existing in the form of ilmenite. Most of my country's ilmenite is used as raw material for the sulfuric acid process in the production of titanium dioxide, with only a small portion processed into titanium-rich materials. However, the sulfuric acid process for titanium dioxide production generates 8-10 tons of waste acid and 3-4 tons of ferrous sulfate for every ton of titanium dioxide produced. Furthermore, the sulfuric acid process for titanium dioxide production is difficult to produce titanium-rich materials suitable for fluidized bed chlorination.

[0010] In recent years, with the rapid development of my country's steel industry, the demand for iron ore has surged. However, my country's scarcity of high-quality iron ore resources, low utilization rates of complex and difficult-to-process iron ores, and insufficient production capacity of domestic iron ore producers have led to a severe supply shortage in the domestic iron ore market. my country's dependence on imported iron ore has increased year by year, significantly threatening the security and stability of my country's steel industry. Therefore, the efficient development of complex and difficult-to-process iron ores to alleviate my country's dependence on imported iron ore has become an urgent task. Currently, the comprehensive utilization rate of ilmenite resources in my country is still very low, and resource waste is widespread. Therefore, given the current status of ilmenite resources, developing new technologies for the efficient and comprehensive utilization of ilmenite resources and achieving the deep development and full utilization of titanium and iron resources is of profound significance. In the electroreduction of iron to produce iron using acidic solutions, the iron-containing electrolyte is generally mainly ferrous iron, and the raw materials mainly come from pyrite and ilmenite containing ferrous iron. When using ilmenite as a raw material, there are fewer reports on its use, and a series of new challenges arise: mismatch between the acid produced at the electroreduction anode and the leaching acidity, mismatch between the final leaching acid and the electroreduction cathode acidity, leading to difficulties in circulating the sulfuric acid medium, intensified acidolysis, water circulation in membrane (ion-exchange membrane) electroreduction, purification of ferric sulfate solution, and challenges in utilizing acidolysis / purification residues. In summary, given the current status of ilmenite resources, developing new technologies for the efficient and low-carbon utilization of ilmenite resources to achieve in-depth development and full utilization of these resources is of paramount importance. Summary of the Invention

[0011] To address the aforementioned problems, this invention proposes a system and method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite, thereby achieving the preparation of high-purity iron, titanium dioxide, and high-end sponge titanium, as well as the recycling of by-product resources. To achieve this objective, this invention employs the following technical solution:

[0012] The present invention proposes a system for simultaneously producing low-carbon pure iron, titanium dioxide and high-end sponge titanium from ilmenite. The system includes an acid hydrolysis separation process 1, a dissolution and purification process 2, a battery ironmaking process 3, a solution depletion process 4, a titanium dioxide process 5, and a high-end sponge titanium process 6.

[0013] The acid hydrolysis separation process 1 includes an acid hydrolysis device 1-1 and an ferro-titanium separation device 1-2;

[0014] The dissolution and purification process 2 includes a dissolution and filtration device 2-1, a sulfur dioxide heat exchanger 2-2, a high-temperature desulfurization device 2-3, an iron molten metal purification device 2-4, and a solar furnace 2-5;

[0015] The battery ironmaking process 3 includes an electrometallurgical device 3-1, a cathode liquid heat exchange device 3-2, and an anode liquid heat exchange device 3-3;

[0016] The solution depletion process 4 includes a sulfuric acid concentration device 4-1 and an electro-depletion device 4-2;

[0017] The titanium dioxide process 5 includes a titanium liquid purification device 5-1, a fine particle hydrolysis device 5-2, a fine particle fluidized bed calcination device 5-3, and a surface modification treatment device 5-4.

[0018] The high-end sponge titanium process 6 includes a coarse-grain hydrolysis device 6-1, a coarse-grain fluidized bed calcination device 6-2, a fluidized bed chlorination device 6-3, and a magnesium thermal reduction device 6-4;

[0019] The feed inlet of the acidolysis device 1-1 is connected to ilmenite via a pipeline; the liquid inlet of the acidolysis device 1-1 is connected to the liquid outlet of the sulfuric acid concentration device 4-1 and the main sulfuric acid solution pipe via a pipeline; the acidolysis device 1-1 is equipped with a heat exchange jacket, the jacket inlet is connected to the high-temperature medium of the solar furnace via a pipeline, and the jacket outlet is connected to the low-temperature medium of the solar furnace via a pipeline; the liquid outlet of the acidolysis device 1-1 is connected to the liquid inlet of the ilmenite separation device 1-2 via a pipeline; the liquid outlet of the ilmenite separation device 1-2 is connected to the liquid inlet of the titanium liquid purification device 5-1 via a pipeline; the discharge outlet of the ilmenite separation device 1-2 is connected to the feed inlet of the dissolving and filtering device 2-1 via a pipeline.

[0020] The inlet of the dissolving filter 2-1 is connected to the regenerated water outlet of the sulfuric acid concentration device 4-1 via a pipeline; the air inlet of the dissolving filter 2-1 is connected to the sulfur dioxide outlet of the sulfur dioxide heat exchanger 2-2 via a pipeline; the slag outlet of the dissolving filter 2-1 is connected to the feed inlet of the high-temperature desulfurization device 2-3 via a pipeline; the liquid outlet of the dissolving filter 2-1 is connected to the liquid inlet of the molten iron purification device 2-4 via a pipeline; the high-temperature air inlet of the sulfur dioxide heat exchanger 2-2 is connected to the air outlet of the high-temperature desulfurization device 2-3 via a pipeline; the air inlet of the sulfur dioxide heat exchanger 2-2 is connected to the main air pipe; the high-temperature air outlet of the sulfur dioxide heat exchanger 2-2 is connected to the gas inlet of the cathode liquid heat exchanger 3-2 and the gas inlet of the anolyte heat exchanger 3-3 via a pipeline. The following connections are made: the gas inlet of the high-temperature desulfurization device 2-3 is connected to the hydrogen outlet of the electrometallurgical device 3-1 and the hydrogen outlet of the electro-depletion device 4-2 via pipelines; the slag inlet of the high-temperature desulfurization device 2-3 is connected to the slag outlet of the molten iron purification device 2-4 via pipelines; the solid material outlet of the high-temperature desulfurization device 2-3 is connected to the cement clinker product via pipelines; the high-temperature desulfurization device 2-3 has an internal heat exchange jacket, the high-temperature medium inlet of the heat exchange jacket is connected to the high-temperature medium outlet of the solar furnace 2-5 via pipelines; the low-temperature medium outlet of the heat exchange jacket is connected to the low-temperature medium inlet of the solar furnace 2-5 via pipelines; the solar furnace 2-5 is provided with a window for receiving solar radiation; the liquid outlet of the molten iron purification device 2-4 is connected to the liquid inlet of the cathode liquid heat exchange device 3-2 via pipelines.

[0021] The anode inlet of the electrometallurgical device 3-1 is connected to the outlet of the anolyte heat exchanger 3-3 via a pipe; the cathode inlet of the electrometallurgical device 3-1 is connected to the outlet of the cathode heat exchanger 3-2 via a pipe; the anode outlet of the electrometallurgical device 3-1 is connected to the anode inlet of the electro-depletion device 4-2 via a pipe; the anode outlet of the electrometallurgical device 3-1 is connected to an oxygen product pipeline; the cathode outlet of the electrometallurgical device 3-1 is connected to the cathode inlet of the electro-depletion device 4-2 via a pipe; the cathode outlet of the electrometallurgical device 3-1... The outlet of the electrode is connected to the hydrogen product pipeline; the cathode of the electrometallurgical device 3-1 is designed with an open cathode, and pure iron is the final product; the anode of the electrometallurgical device 3-1 is connected to the positive electrode of the green electricity through a conductive copper beam; the cathode of the electrometallurgical device 3-1 is connected to the negative electrode of the green electricity through a conductive copper beam; the outlet of the cathode liquid heat exchange device 3-2 is connected to the low-temperature air exhaust port through a pipeline; the outlet of the anode liquid heat exchange device 3-3 is connected to the low-temperature air exhaust port through a pipeline; the inlet of the anode liquid heat exchange device 3-3 is connected to the cathode outlet of the electro-depletion device 4-2 through a pipeline.

[0022] The inlet of the sulfuric acid concentration device 4-1 is connected to the anode outlet of the electro-depletion device 4-2 via a pipeline; the sulfuric acid concentration device 4-1 has an internal heat exchange jacket, the high-temperature medium inlet of which is connected to the high-temperature medium outlet of the solar furnace 2-5 via a pipeline; the low-temperature medium outlet of which is connected to the low-temperature medium inlet of the solar furnace 2-5 via a pipeline; the anode of the electro-depletion device 4-2 is connected to the positive electrode of the green electricity via a conductive copper beam; the cathode of the electro-depletion device 4-2 is connected to the negative electrode of the green electricity via a conductive copper beam; the anode outlet of the electro-depletion device 4-2 is connected to the oxygen product pipeline; the cathode outlet of the electro-depletion device 4-2 is connected to the hydrogen product pipeline; the cathode of the electro-depletion device 4-2 has an open design, and pure iron is the final product.

[0023] The outlet of the titanium liquid purification device 5-1 is connected to the inlet of the fine-particle hydrolysis device 5-2 and the coarse-particle hydrolysis device 6-1 via a pipeline; the outlet of the fine-particle hydrolysis device 5-2 is connected to the inlet of the fine-particle fluidized bed calcination device 5-3 via a pipeline; the outlet of the fine-particle fluidized bed calcination device 5-3 is connected to the inlet of the surface modification treatment device 5-4 via a pipeline; and the outlet of the surface modification treatment device 5-4 is connected to the sulfuric acid process titanium dioxide product pipeline.

[0024] The outlet of the coarse-grained hydrolysis device 6-1 is connected to the inlet of the coarse-grained fluidized bed calcination device 6-2 via a pipeline; the outlet of the coarse-grained fluidized bed calcination device 6-2 is connected to the inlet of the fluidized bed chlorination device 6-3 via a pipeline; the inlet of the fluidized bed chlorination device 6-3 is connected to the inlets of chlorine gas and carbon powder via a pipeline; the outlet of the fluidized bed chlorination device 6-3 is connected to the inlet of the magnesiac reduction device 6-4 via a pipeline; the inlet of the magnesiac reduction device 6-4 is connected to magnesium ingots via a pipeline; and the outlet of the magnesiac reduction device 6-4 is connected to high-end sponge titanium products via a pipeline.

[0025] This invention provides a method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite using the aforementioned system, comprising the following steps:

[0026] Ilmenite reacts with concentrated sulfuric acid from the sulfuric acid concentration unit 4-1 and the sulfuric acid solution main in the acidolysis unit 1-1 to produce black titanium solution; the heat of the acidolysis unit 1-1 is provided by the high-temperature medium circulation of the solar furnace; the black titanium solution passes through the titanium-iron separation unit 1-2 to obtain iron salt crystals and titanium oxysulfate solution; the titanium oxysulfate solution is sent to the titanium solution purification unit 5-1; the iron salt crystals enter the dissolution and filtration unit 2-1;

[0027] Iron salt crystals, reclaimed water, and sulfur dioxide are fed into dissolving and filtering device 2-1 to obtain a dissolving solution and a dissolving residue. The dissolving solution passes through iron molten iron purification device 2-4 to obtain an iron salt solution and a purification residue. The iron salt solution is sent to the cathode chamber of electrometallurgical device 3-1 via cathode liquid heat exchange device 3-2. The dissolving residue, purification residue, and hydrogen are fed into high-temperature desulfurization device 2-3 to obtain high-temperature sulfur dioxide and cement clinker. The cement clinker is discharged for further treatment. The hydrogen is a byproduct of the cathode reaction in electrometallurgical device 3-1 and electro-depletion device 4-2. Solar furnace 2-5 converts solar energy into thermal energy and provides heat for the high-temperature desulfurization device 2-3 process through high-temperature medium circulation. High-temperature sulfur dioxide and air exchange heat through sulfur dioxide heat exchanger 2-2 to obtain low-temperature sulfur dioxide and high-temperature air. The high-temperature air is fed into cathode liquid heat exchange device 3-2 and anolyte heat exchange device 3-3 respectively to heat the cathode liquid and anolyte.

[0028] The iron salt solution undergoes an electroreduction reaction in the cathode chamber of the electrometallurgical device 3-1 to obtain pure iron, a low-concentration iron salt solution, and hydrogen as a byproduct. The pure iron is the final product, the low-concentration iron salt solution is sent to the cathode chamber of the electro-depletion device 4-2, part of the hydrogen is sent to the high-temperature desulfurization process, and the remainder is collected as hydrogen product. The dilute sulfuric acid solution from the cathode chamber of the electro-depletion device 4-2 is preheated by the anolyte heat exchanger 3-3 and then introduced into the anode chamber of the electrometallurgical device 3-1 to undergo an electro-oxidation reaction, producing sulfuric acid and oxygen. The sulfuric acid solution is sent to the electro-depletion device 4-2, and the oxygen is collected as a product. The anode in the electrometallurgical device 3-1 is connected to the positive terminal of the DC power supply through a conductive copper beam; the cathode in the electrometallurgical device 3-1 is connected to the negative terminal of the DC power supply through a conductive copper beam.

[0029] In the cathode chamber of the electro-depletion unit 4-2, a dilute ferrous sulfate solution undergoes an electroreduction reaction to produce a dilute sulfuric acid solution, pure iron, and hydrogen as a byproduct. Part of the hydrogen is sent to the high-temperature desulfurization process, and the remainder is collected as a hydrogen product. In the anode chamber of the electro-depletion unit 4-2, an electro-oxidation reaction occurs to produce sulfuric acid and oxygen. The sulfuric acid solution is sent to the sulfuric acid concentration unit 4-1 to obtain regenerated water and concentrated sulfuric acid. The high-temperature medium circulation of the solar furnace provides heat to the sulfuric acid concentration unit 4-1.

[0030] Titanium oxysulfate is purified by titanium liquid purification device 5-1 to obtain purified titanium oxysulfate solution; part of the purified titanium oxysulfate solution is sent to fine particle hydrolysis device 5-2 to obtain fine particle metatitanic acid; fine particle metatitanic acid is sent to fine particle fluidized bed calcination device 5-3 to obtain calcined product; calcined product is sent to surface modification treatment device 5-4 to obtain sulfuric acid process titanium dioxide product.

[0031] After partial purification, the titanium oxysulfate solution is fed into a coarse-grained hydrolysis unit 6-1 to obtain coarse-grained metatitanic acid; the coarse-grained metatitanic acid is fed into a coarse-grained fluidized bed calcination unit 6-2 to obtain coarse-grained titanium dioxide; the coarse-grained titanium dioxide, chlorine gas, and carbon powder are fed into a fluidized bed chlorination unit 6-3 to obtain titanium tetrachloride; titanium tetrachloride and magnesium ingots are fed into a magnesothermic reduction unit 6-4 to obtain high-end sponge titanium products.

[0032] One of the features of this invention is that: ilmenite is used to simultaneously produce low-carbon pure iron, titanium dioxide, and high-end sponge titanium.

[0033] The second feature of this invention is that ilmenite simultaneously achieves efficient utilization of both titanium and iron.

[0034] The third feature of this invention is that the iron salt dissolution filtration device 2-1 achieves the purpose of valence state control and promotes dissolution by reducing ferrous ions with sulfur dioxide.

[0035] The fourth feature of this invention is that the electrometallurgy is electroreduced iron, which uses electrical energy to reduce iron and produces no carbon dioxide emissions.

[0036] The fifth feature of this invention is that: electro-depletion is the process of reducing the iron ion concentration by using electro-depletion to achieve water circulation. In the electro-depletion device 4-2, the diaphragm material is an ion-exchange membrane or a porous membrane, wherein the permeation rate of the porous membrane is 1%-40%, and the current density is 50 A / m³. 2 - 1000 A / m 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, and the cathode is made of iron or titanium. The temperature range is 20 ℃ to 100 ℃.

[0037] The sixth feature of this invention is that it obtains oxygen as a byproduct.

[0038] The seventh feature of this invention is: hydrogen recovery and utilization.

[0039] The eighth feature of this invention is that the tailings are completely recycled.

[0040] The ninth feature of this invention is that the iron oxide powder process adopts fine-particle fluidized bed calcination, with a calcination temperature of 300-800 ℃ and a residence time of 5-30 min, which has the purpose of saving energy and improving efficiency.

[0041] The tenth feature of this invention is that the high-end sponge titanium process adopts coarse-grained crystallization hydrolysis to obtain high-purity coarse-grained metatitanic acid with a particle size greater than 100 micrometers and a purity greater than 95%, and the high-end sponge titanium has a purity greater than 99%.

[0042] The eleventh feature of this invention is that high-purity coarse-grained metatitanic acid is obtained by fluidized bed calcination to obtain sand-like titanium dioxide, which has the purpose of saving energy and improving efficiency.

[0043] The twelfth feature of this invention is that: the coarse-grained hydrolysis process combined with the coarse-grained fluidized bed calcination process can produce coarse-grained titanium dioxide with a purity of over 95% and a particle size greater than 100 micrometers; the coarse-grained titanium dioxide has a particle size range suitable for fluidized bed chlorination, which facilitates fluidized bed chlorination operation.

[0044] The thirteenth feature of this invention is that high-grade titanium dioxide produces almost no chlorination residue during the fluidized bed chlorination process, which is beneficial for continuous system operation.

[0045] The fourteenth feature of this invention is that high-grade titanium dioxide can be used to obtain high-purity titanium tetrachloride, which, through magnesothermic reduction, yields high-end sponge titanium for use in the defense, military, and aerospace fields.

[0046] The fifteenth feature of this invention is that it adopts a method of cross-circulation of catholyte and anolyte, which has the characteristics of continuous and efficient production.

[0047] The sixteenth feature of this invention is that the energy of the acid hydrolysis device, the sulfuric acid concentration device, and the high-temperature desulfurization device can be recycled by a solar furnace.

[0048] The seventeenth feature of the present invention is that the heat for the dissolution filtration device can be provided by a sulfur dioxide heat exchanger.

[0049] The eighteenth feature of the present invention is that the heat of the electrometallurgical cathode liquid and anolyte can be provided by the cathode liquid heat exchanger and the anolyte heat exchanger.

[0050] The nineteenth feature of the present invention is that, in the electrometallurgical device 3-1, the diaphragm material is an ion-exchange membrane or a porous membrane, wherein the permeation rate of the porous membrane is 1%-40%, and the current density is 100 A / m. 2 - 2000 A / m 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, and the cathode is made of iron, copper, titanium or stainless steel. The reaction temperature is 60 ℃-100 ℃, the current efficiency is above 95%, the cathode iron purity is above 99%, and the DC power consumption per ton of iron is less than 3500 kWh.

[0051] The twentieth feature of the present invention is that the high-temperature desulfurization device 2-3 adopts a fluidized bed or rotary kiln reactor, the reaction temperature is 1000 ℃-1500 ℃, and the desulfurization rate is above 99%.

[0052] This invention belongs to the fields of energy and metallurgy. Specifically, it discloses a system and method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite. The ilmenite is directly acidified through an acid-dissociation process to separate a titanium oxysulfate solution and iron salt crystals. A purification process yields a purified iron salt solution, simultaneously realizing the resource utilization of the dissolving / purifying slag and the recycling of sulfur. Pure iron is prepared through a battery-based ironmaking process and a solution depletion process, thereby achieving the recycling of sulfuric acid and hydrogen and oxygen products. In the titanium dioxide process, fine-particle fluidized bed calcination technology is used to prepare titanium dioxide using the sulfuric acid process. In the high-end sponge titanium process, coarse-particle fluidized bed calcination is used to obtain high-end sponge titanium. This invention is suitable for large-scale continuous production of low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite, and has advantages such as high efficiency, low energy consumption, no pollution, and good economic benefits.

[0053] Compared with the prior art, the present invention has the following outstanding advantages:

[0054] (1) Electrometallurgy and electrodepletion energy sources are green electricity, and the hydrogen and oxygen produced can be recycled and reused;

[0055] (2) The heat of the catholyte and anolyte in electrometallurgy comes from the catholyte heat exchanger and the anolyte heat exchanger;

[0056] (3) The heat in this process can be recycled, minimizing heat loss and reducing energy consumption;

[0057] (4) Sulfuric acid solution and sulfur dioxide gas can be recycled within the system without emission, making it safe and environmentally friendly;

[0058] (5) This process can simultaneously achieve efficient utilization of titanium and iron.

[0059] (6) The entire process is carbon-free;

[0060] (7) The anolyte and catholyte solutions in this system are in a cross-circulation manner;

[0061] (8) The tailings produced can be fully utilized to make cement clinker;

[0062] (9) The process is simple, the production cost is low, and the product purity is high;

[0063] The technology for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite using this invention not only yields high-purity iron, titanium dioxide, and high-end sponge titanium, but also achieves zero carbon emissions throughout the entire process, heat recycling, complete resource utilization of tailings, recycling of byproducts such as sulfuric acid and sulfur dioxide, and recovery and reuse of hydrogen and oxygen. This invention is suitable for large-scale, continuous processing of ilmenite to simultaneously produce low-carbon pure iron, titanium dioxide, and high-end sponge titanium, and has advantages such as high efficiency, low energy consumption, no pollution, and good economic benefits. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the configuration of the ilmenite system proposed in this invention for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium.

[0065] Figure Labels

[0066] 1. Acid hydrolysis separation process

[0067] 1-1 Acidolysis apparatus 1-2 Titanium-iron separation apparatus

[0068] 2. Dissolving and Purification Process

[0069] 2-1 Dissolution and filtration device 2-2 Sulfur dioxide heat exchanger

[0070] 2-3 High-temperature desulfurization unit 2-4 Molten iron purification unit

[0071] 2-5 Solar Furnace

[0072] 3 Battery Ironmaking Process

[0073] 3-1 Electrometallurgical Equipment 3-2 Cathode Liquid Heat Exchanger

[0074] 3-3 Anode Liquid Heat Exchanger

[0075] 4 Solution depletion process

[0076] 4-1 Sulfuric acid concentration unit 4-2 Electrolysis unit

[0077] 5. Titanium Dioxide Process

[0078] 5-1 Titanium liquid purification device 5-2 Fine particle hydrolysis device

[0079] 5-3 Fine-particle fluidized bed calcination apparatus 5-4 Surface modification treatment apparatus

[0080] 6. High-end sponge titanium process

[0081] 6-1 Coarse-grained hydrolysis unit; 6-2 Coarse-grained fluidized bed calcination unit

[0082] 6-3 Fluidized bed chlorination unit 6-4 Magnesium thermal reduction unit Detailed Implementation

[0083] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. It is worth noting that the embodiments are only used to illustrate the technical solutions of the present invention, and not to limit it. Figure 1 This is a schematic diagram of a system and method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to the present invention.

[0084] Example 1

[0085] Combination Figure 1 The system used in this embodiment is a system for simultaneously producing low-carbon pure iron, titanium dioxide and high-end sponge titanium from ilmenite. The system includes an acid hydrolysis separation process 1, a dissolution and purification process 2, a battery ironmaking process 3, a solution depletion process 4, a titanium dioxide process 5, and a high-end sponge titanium process 6.

[0086] The acid hydrolysis separation process 1 includes an acid hydrolysis device 1-1 and an ferro-titanium separation device 1-2;

[0087] The dissolution and purification process 2 includes a dissolution and filtration device 2-1, a sulfur dioxide heat exchanger 2-2, a high-temperature desulfurization device 2-3, an iron molten metal purification device 2-4, and a solar furnace 2-5;

[0088] The battery ironmaking process 3 includes an electrometallurgical device 3-1, a cathode liquid heat exchange device 3-2, and an anode liquid heat exchange device 3-3;

[0089] The solution depletion process 4 includes a sulfuric acid concentration device 4-1 and an electro-depletion device 4-2;

[0090] The titanium dioxide process 5 includes a titanium liquid purification device 5-1, a fine particle hydrolysis device 5-2, a fine particle fluidized bed calcination device 5-3, and a surface modification treatment device 5-4.

[0091] The high-end sponge titanium process 6 includes a coarse-grain hydrolysis device 6-1, a coarse-grain fluidized bed calcination device 6-2, a fluidized bed chlorination device 6-3, and a magnesium thermal reduction device 6-4;

[0092] The feed inlet of the acidolysis device 1-1 is connected to ilmenite via a pipeline; the liquid inlet of the acidolysis device 1-1 is connected to the liquid outlet of the sulfuric acid concentration device 4-1 and the main sulfuric acid solution pipe via a pipeline; the acidolysis device 1-1 is equipped with a heat exchange jacket, the jacket inlet is connected to the high-temperature medium of the solar furnace via a pipeline, and the jacket outlet is connected to the low-temperature medium of the solar furnace via a pipeline; the liquid outlet of the acidolysis device 1-1 is connected to the liquid inlet of the ilmenite separation device 1-2 via a pipeline; the liquid outlet of the ilmenite separation device 1-2 is connected to the liquid inlet of the titanium liquid purification device 5-1 via a pipeline; the discharge outlet of the ilmenite separation device 1-2 is connected to the feed inlet of the dissolution and filtration device 2-1 via a pipeline.

[0093] The inlet of the dissolving filter 2-1 is connected to the regenerated water outlet of the sulfuric acid concentration device 4-1 via a pipeline; the air inlet of the dissolving filter 2-1 is connected to the sulfur dioxide outlet of the sulfur dioxide heat exchanger 2-2 via a pipeline; the slag outlet of the dissolving filter 2-1 is connected to the feed inlet of the high-temperature desulfurization device 2-3 via a pipeline; the liquid outlet of the dissolving filter 2-1 is connected to the liquid inlet of the molten iron purification device 2-4 via a pipeline; the high-temperature air inlet of the sulfur dioxide heat exchanger 2-2 is connected to the air outlet of the high-temperature desulfurization device 2-3 via a pipeline; the air inlet of the sulfur dioxide heat exchanger 2-2 is connected to the main air pipe; the high-temperature air outlet of the sulfur dioxide heat exchanger 2-2 is connected to the gas inlet of the cathode liquid heat exchanger 3-2 and the gas inlet of the anolyte heat exchanger 3-3 via a pipeline. The following connections are made: the gas inlet of the high-temperature desulfurization device 2-3 is connected to the hydrogen outlet of the electrometallurgical device 3-1 and the hydrogen outlet of the electro-depletion device 4-2 via pipelines; the slag inlet of the high-temperature desulfurization device 2-3 is connected to the slag outlet of the molten iron purification device 2-4 via pipelines; the solid material outlet of the high-temperature desulfurization device 2-3 is connected to the cement clinker product via pipelines; the high-temperature desulfurization device 2-3 has an internal heat exchange jacket, the high-temperature medium inlet of the heat exchange jacket is connected to the high-temperature medium outlet of the solar furnace 2-5 via pipelines; the low-temperature medium outlet of the heat exchange jacket is connected to the low-temperature medium inlet of the solar furnace 2-5 via pipelines; the solar furnace 2-5 is provided with a window for receiving solar radiation; the liquid outlet of the molten iron purification device 2-4 is connected to the liquid inlet of the cathode liquid heat exchange device 3-2 via pipelines.

[0094] The anode inlet of the electrometallurgical device 3-1 is connected to the outlet of the anolyte heat exchanger 3-3 via a pipe; the cathode inlet of the electrometallurgical device 3-1 is connected to the outlet of the cathode heat exchanger 3-2 via a pipe; the anode outlet of the electrometallurgical device 3-1 is connected to the anode inlet of the electro-depletion device 4-2 via a pipe; the anode outlet of the electrometallurgical device 3-1 is connected to an oxygen product pipeline; the cathode outlet of the electrometallurgical device 3-1 is connected to the cathode inlet of the electro-depletion device 4-2 via a pipe; the cathode outlet of the electrometallurgical device 3-1... The outlet of the electrode is connected to the hydrogen product pipeline; the cathode of the electrometallurgical device 3-1 is designed with an open cathode, and pure iron is the final product; the anode of the electrometallurgical device 3-1 is connected to the positive electrode of the green electricity through a conductive copper beam; the cathode of the electrometallurgical device 3-1 is connected to the negative electrode of the green electricity through a conductive copper beam; the outlet of the cathode liquid heat exchange device 3-2 is connected to the low-temperature air exhaust port through a pipeline; the outlet of the anode liquid heat exchange device 3-3 is connected to the low-temperature air exhaust port through a pipeline; the inlet of the anode liquid heat exchange device 3-3 is connected to the cathode outlet of the electro-depletion device 4-2 through a pipeline.

[0095] The inlet of the sulfuric acid concentration device 4-1 is connected to the anode outlet of the electro-depletion device 4-2 via a pipeline; the sulfuric acid concentration device 4-1 has an internal heat exchange jacket, the high-temperature medium inlet of which is connected to the high-temperature medium outlet of the solar furnace 2-5 via a pipeline; the low-temperature medium outlet of which is connected to the low-temperature medium inlet of the solar furnace 2-5 via a pipeline; the anode of the electro-depletion device 4-2 is connected to the positive electrode of the green electricity via a conductive copper beam; the cathode of the electro-depletion device 4-2 is connected to the negative electrode of the green electricity via a conductive copper beam; the anode outlet of the electro-depletion device 4-2 is connected to the oxygen product pipeline; the cathode outlet of the electro-depletion device 4-2 is connected to the hydrogen product pipeline; the cathode of the electro-depletion device 4-2 has an open design, and pure iron is the final product.

[0096] The outlet of the titanium liquid purification device 5-1 is connected to the inlet of the fine-particle hydrolysis device 5-2 and the coarse-particle hydrolysis device 6-1 via a pipeline; the outlet of the fine-particle hydrolysis device 5-2 is connected to the inlet of the fine-particle fluidized bed calcination device 5-3 via a pipeline; the outlet of the fine-particle fluidized bed calcination device 5-3 is connected to the inlet of the surface modification treatment device 5-4 via a pipeline; and the outlet of the surface modification treatment device 5-4 is connected to the sulfuric acid process titanium dioxide product pipeline.

[0097] The outlet of the coarse-grained hydrolysis device 6-1 is connected to the inlet of the coarse-grained fluidized bed calcination device 6-2 via a pipeline; the outlet of the coarse-grained fluidized bed calcination device 6-2 is connected to the inlet of the fluidized bed chlorination device 6-3 via a pipeline; the inlet of the fluidized bed chlorination device 6-3 is connected to the inlets of chlorine gas and carbon powder via a pipeline; the outlet of the fluidized bed chlorination device 6-3 is connected to the inlet of the magnesiac reduction device 6-4 via a pipeline; the inlet of the magnesiac reduction device 6-4 is connected to magnesium ingots via a pipeline; and the outlet of the magnesiac reduction device 6-4 is connected to high-end sponge titanium products via a pipeline.

[0098] Example 2

[0099] This embodiment employs the method described in Example 1 for processing ilmenite to simultaneously produce low-carbon pure iron, titanium dioxide, and high-end sponge titanium, including the following steps:

[0100] Ilmenite reacts with concentrated sulfuric acid from the sulfuric acid concentration unit 4-1 and the sulfuric acid solution main in the acidolysis unit 1-1 to produce black titanium solution; the heat of the acidolysis unit 1-1 is provided by the high-temperature medium circulation of the solar furnace; the black titanium solution passes through the titanium-iron separation unit 1-2 to obtain iron salt crystals and titanium oxysulfate solution; the titanium oxysulfate solution is sent to the titanium solution purification unit 5-1; the iron salt crystals enter the dissolution and filtration unit 2-1;

[0101] Iron salt crystals, reclaimed water, and sulfur dioxide are fed into dissolving and filtering device 2-1 to obtain a dissolving solution and a dissolving residue. The dissolving solution passes through iron molten iron purification device 2-4 to obtain an iron salt solution and a purification residue. The iron salt solution is sent to the cathode chamber of electrometallurgical device 3-1 via cathode liquid heat exchange device 3-2. The dissolving residue, purification residue, and hydrogen are fed into high-temperature desulfurization device 2-3 to obtain high-temperature sulfur dioxide and cement clinker. The cement clinker is discharged for further treatment. The hydrogen is a byproduct of the cathode reaction in electrometallurgical device 3-1 and electro-depletion device 4-2. Solar furnace 2-5 converts solar energy into thermal energy and provides heat for the high-temperature desulfurization device 2-3 process through high-temperature medium circulation. High-temperature sulfur dioxide and air exchange heat through sulfur dioxide heat exchanger 2-2 to obtain low-temperature sulfur dioxide and high-temperature air. The high-temperature air is fed into cathode liquid heat exchange device 3-2 and anolyte heat exchange device 3-3 respectively to heat the cathode liquid and anolyte.

[0102] The iron salt solution undergoes an electroreduction reaction in the cathode chamber of the electrometallurgical device 3-1 to obtain pure iron, a low-concentration iron salt solution, and hydrogen as a byproduct. The pure iron is the final product, the low-concentration iron salt solution is sent to the cathode chamber of the electro-depletion device 4-2, part of the hydrogen is sent to the high-temperature desulfurization process, and the remainder is collected as hydrogen product. The dilute sulfuric acid solution from the cathode chamber of the electro-depletion device 4-2 is preheated by the anolyte heat exchanger 3-3 and then introduced into the anode chamber of the electrometallurgical device 3-1 to undergo an electro-oxidation reaction, producing sulfuric acid and oxygen. The sulfuric acid solution is sent to the electro-depletion device 4-2, and the oxygen is collected as a product. The anode in the electrometallurgical device 3-1 is connected to the positive terminal of the DC power supply through a conductive copper beam; the cathode in the electrometallurgical device 3-1 is connected to the negative terminal of the DC power supply through a conductive copper beam.

[0103] In the cathode chamber of the electro-depletion unit 4-2, a dilute ferrous sulfate solution undergoes an electroreduction reaction to produce a dilute sulfuric acid solution, pure iron, and hydrogen as a byproduct. Part of the hydrogen is sent to the high-temperature desulfurization process, and the remainder is collected as a hydrogen product. In the anode chamber of the electro-depletion unit 4-2, an electro-oxidation reaction occurs to produce sulfuric acid and oxygen. The sulfuric acid solution is sent to the sulfuric acid concentration unit 4-1 to obtain regenerated water and concentrated sulfuric acid. The high-temperature medium circulation of the solar furnace provides heat to the sulfuric acid concentration unit 4-1.

[0104] Titanium oxysulfate is purified by titanium liquid purification device 5-1 to obtain purified titanium oxysulfate solution; part of the purified titanium oxysulfate solution is sent to fine particle hydrolysis device 5-2 to obtain fine particle metatitanic acid; fine particle metatitanic acid is sent to fine particle fluidized bed calcination device 5-3 to obtain calcined product; calcined product is sent to surface modification treatment device 5-4 to obtain sulfuric acid process titanium dioxide product.

[0105] After partial purification, the titanium oxysulfate solution is fed into a coarse-grained hydrolysis unit 6-1 to obtain coarse-grained metatitanic acid; the coarse-grained metatitanic acid is fed into a coarse-grained fluidized bed calcination unit 6-2 to obtain coarse-grained titanium dioxide; the coarse-grained titanium dioxide, chlorine gas, and carbon powder are fed into a fluidized bed chlorination unit 6-3 to obtain titanium tetrachloride; titanium tetrachloride and magnesium ingots are fed into a magnesothermic reduction unit 6-4 to obtain high-end sponge titanium products.

[0106] Example 3

[0107] This embodiment uses the system and method of Embodiments 1-2, taking ilmenite concentrate from a certain enterprise as the processing object; in the acidolysis device 1-1, sulfuric acid acidolysis is used at a reaction temperature of 100 ℃, with an acidolysis rate of 99%; the acidolysis process is provided with heat by the high-temperature medium circulation of the solar furnace 2-5; in the iron salt dissolution and filtration device 2-1, sulfur dioxide is used to reduce ferric ions, which is used for valence state control and to promote dissolution; the iron dioxide process uses fine-particle fluidized bed calcination at a calcination temperature of 300 ℃ and a residence time of 30 min; the high-end sponge titanium process uses coarse-particle crystallization hydrolysis to obtain high-purity coarse-particle metatitanic acid with a particle size of 100 micrometers and a purity of 95%, and high-end sponge titanium with a purity of 99%; the heat of the acidolysis device, sulfuric acid concentration device, and high-temperature desulfurization device is provided by the circulating medium of the solar furnace; in the electrometallurgical device 3-1, the diaphragm material is an ion-exchange membrane, and the current density is 100 A / m 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, and the cathode is made of iron, copper, titanium, or stainless steel. The reaction temperature is 60 ℃, the current efficiency is 95%, the cathode iron purity is 99%, and the DC power consumption per ton of iron is 3500 kWh. In the high-temperature desulfurization device 2-3, a fluidized bed reactor is used, the reaction temperature is 1000 ℃, and the desulfurization rate is 99%. In the electrolytic desulfurization device 4-2, the diaphragm material is an ion-exchange membrane, and the current density is 50 A / m. 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, the cathode is made of iron or titanium, and the temperature is 20 ℃.

[0108] Example 4

[0109] This embodiment uses the system and method of Embodiments 1-2, taking ilmenite concentrate from a certain enterprise as the processing object; in the acidolysis device 1-1, sulfuric acid acidolysis is used at a reaction temperature of 100 ℃, and the acidolysis rate is 99%; the acidolysis process is provided with heat by the high-temperature medium circulation of the solar furnace 2-5; in the iron salt dissolution and filtration device 2-1, sulfur dioxide is used to reduce ferric ions for valence control and to promote dissolution; the iron dioxide process uses fine-particle fluidized bed calcination at a calcination temperature of 800 ℃ and a residence time of 5 min; the high-end sponge titanium process uses coarse-particle crystallization hydrolysis to obtain high-purity coarse-particle metatitanic acid with a particle size of 100 micrometers and a purity of 95%, and high-end sponge titanium with a purity of 99%; the heat of the acidolysis device, sulfuric acid concentration device, and high-temperature desulfurization device is provided by the circulating medium of the solar furnace; in the electrometallurgical device 3-1, the diaphragm material is a porous membrane with a permeation rate of 1% and a current density of 2000 A / m 2The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, and the cathode is made of iron, copper, titanium, or stainless steel. The reaction temperature is 100 ℃, the current efficiency is 96%, the cathode iron purity is 99.9%, and the DC power consumption per ton of iron is 3400 kWh. In the high-temperature desulfurization device 2-3, a rotary kiln reactor is used, the reaction temperature is 1500 ℃, and the desulfurization rate is 99%. In the electro-desulfurization device 4-2, the diaphragm material is a porous membrane with a permeation rate of 1% and a current density of 1000 A / m. 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, the cathode is made of iron or titanium, and the temperature is 100 ℃.

[0110] Example 5

[0111] This embodiment uses the system and method of Embodiments 1-2, taking ilmenite concentrate from a certain enterprise as the processing object; in the acidolysis device 1-1, sulfuric acid is used for acidolysis at a reaction temperature of 100 ℃, with an acidolysis rate of 99%; the acidolysis process is provided with heat by the high-temperature medium circulation of the solar furnace 2-5; in the iron salt dissolution and filtration device 2-1, sulfur dioxide is used to reduce ferric ions for valence control and to promote dissolution; the iron dioxide process uses fine-particle fluidized bed calcination at a calcination temperature of 500 ℃ and a residence time of 15 min; the high-end sponge titanium process uses coarse-particle crystallization hydrolysis to obtain high-purity coarse-particle metatitanic acid with a particle size of 150 micrometers and a purity of 95%, and high-end sponge titanium with a purity of 99%; the heat of the acidolysis device, sulfuric acid concentration device, and high-temperature desulfurization device is provided by the circulating medium of the solar furnace; in the electrometallurgical device 3-1, the diaphragm material is a porous membrane with a permeation rate of 40% and a current density of 500 A / m 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, and the cathode is made of iron, copper, titanium, or stainless steel. The reaction temperature is 80 ℃, the current efficiency is 96%, the cathode iron purity is 99.9%, and the DC power consumption per ton of iron is 3400 kWh. In the high-temperature desulfurization device 2-3, a rotary kiln reactor is used, the reaction temperature is 1200 ℃, and the desulfurization rate is 99%. In the electro-desulfurization device 4-2, the diaphragm material is a porous membrane with a permeation rate of 40% and a current density of 500 A / m. 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, the cathode is made of iron or titanium, and the temperature is 80 ℃.

[0112] The parts of this invention not described in detail are well-known in the field.

[0113] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the disclosure of the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A system for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite, characterized in that, The system includes an acid hydrolysis separation process (1), a dissolution and purification process (2), a battery iron smelting process (3), a solution depletion process (4), a titanium dioxide process (5), and a high-end sponge titanium process (6). The acid hydrolysis separation process (1) includes an acid hydrolysis device (1-1) and an ferro-titanium separation device (1-2). The dissolution and purification process (2) includes a dissolution and filtration device (2-1), a sulfur dioxide heat exchanger (2-2), a high-temperature desulfurization device (2-3), an iron molten metal purification device (2-4), and a solar furnace (2-5). The battery ironmaking process (3) includes an electrometallurgical device (3-1), a cathode liquid heat exchange device (3-2), and an anode liquid heat exchange device (3-3). The solution depletion process (4) includes a sulfuric acid concentration unit (4-1) and an electrical depletion unit (4-2). The titanium dioxide process (5) includes a titanium liquid purification device (5-1), a fine particle hydrolysis device (5-2), a fine particle fluidized bed calcination device (5-3), and a surface modification treatment device (5-4). The high-end sponge titanium process (6) includes a coarse-grain hydrolysis device (6-1), a coarse-grain fluidized bed calcination device (6-2), a fluidized bed chlorination device (6-3), and a magnesium thermal reduction device (6-4). The feed inlet of the acidolysis device (1-1) is connected to ilmenite via a pipeline; the liquid inlet of the acidolysis device (1-1) is connected to the liquid outlet of the sulfuric acid concentration device (4-1) and the main sulfuric acid solution pipe via a pipeline; the acidolysis device (1-1) is equipped with a heat exchange jacket, the jacket inlet is connected to the high-temperature medium of the solar furnace via a pipeline, and the jacket outlet is connected to the low-temperature medium of the solar furnace via a pipeline; the liquid outlet of the acidolysis device (1-1) is connected to the liquid inlet of the ilmenite separation device (1-2) via a pipeline; the liquid outlet of the ilmenite separation device (1-2) is connected to the liquid inlet of the titanium liquid purification device (5-1) via a pipeline; the discharge outlet of the ilmenite separation device (1-2) is connected to the feed inlet of the dissolving and filtering device (2-1) via a pipeline. The inlet of the dissolving filter (2-1) is connected to the regenerated water outlet of the sulfuric acid concentration device (4-1) via a pipeline; the air inlet of the dissolving filter (2-1) is connected to the sulfur dioxide outlet of the sulfur dioxide heat exchanger (2-2) via a pipeline; the slag outlet of the dissolving filter (2-1) is connected to the feed inlet of the high-temperature desulfurization device (2-3) via a pipeline; the liquid outlet of the dissolving filter (2-1) is connected to the inlet of the molten iron purification device (2-4) via a pipeline; the high-temperature air inlet of the sulfur dioxide heat exchanger (2-2) is connected to the outlet of the high-temperature desulfurization device (2-3) via a pipeline; the air inlet of the sulfur dioxide heat exchanger (2-2) is connected to the main air pipe; the high-temperature air outlet of the sulfur dioxide heat exchanger (2-2) is connected to the gas inlet of the cathode liquid heat exchanger (3-2) and the gas inlet of the anolyte heat exchanger (3-3). The gas inlet of the high-temperature desulfurization device (2-3) is connected to the hydrogen outlet of the electrometallurgical device (3-1) and the hydrogen outlet of the electro-depletion device (4-2) via pipelines; the slag inlet of the high-temperature desulfurization device (2-3) is connected to the slag outlet of the molten iron purification device (2-4) via pipelines; the solid material outlet of the high-temperature desulfurization device (2-3) is connected to the cement clinker product via pipelines; the high-temperature desulfurization device (2-3) has an internal heat exchange jacket, the high-temperature medium inlet of the heat exchange jacket is connected to the high-temperature medium outlet of the solar furnace (2-5) via pipelines; the low-temperature medium outlet of the heat exchange jacket is connected to the low-temperature medium inlet of the solar furnace (2-5) via pipelines; the solar furnace (2-5) is provided with a window for receiving solar radiation; the liquid outlet of the molten iron purification device (2-4) is connected to the liquid inlet of the cathode liquid heat exchange device (3-2) via pipelines. The anode inlet of the electrometallurgical device (3-1) is connected to the outlet of the anode liquid heat exchange device (3-3) via a pipe; the cathode inlet of the electrometallurgical device (3-1) is connected to the outlet of the cathode liquid heat exchange device (3-2) via a pipe; the anode outlet of the electrometallurgical device (3-1) is connected to the anode inlet of the electro-depletion device (4-2) via a pipe; the anode outlet of the electrometallurgical device (3-1) is connected to an oxygen product pipeline; the cathode outlet of the electrometallurgical device (3-1) is connected to the cathode inlet of the electro-depletion device (4-2) via a pipe; the electrometallurgical device (3-1) The cathode outlet of the electrometallurgical device (3-1) is connected to the hydrogen product pipeline; the cathode of the electrometallurgical device (3-1) is open-ended, and pure iron is the final product; the anode of the electrometallurgical device (3-1) is connected to the positive electrode of the green electricity through a conductive copper beam; the cathode of the electrometallurgical device (3-1) is connected to the negative electrode of the green electricity through a conductive copper beam; the outlet of the cathode liquid heat exchange device (3-2) is connected to the low-temperature air exhaust port through a pipeline; the outlet of the anode liquid heat exchange device (3-3) is connected to the low-temperature air exhaust port through a pipeline; the inlet of the anode liquid heat exchange device (3-3) is connected to the cathode outlet of the electro-depletion device (4-2) through a pipeline. The inlet of the sulfuric acid concentration device (4-1) is connected to the anode outlet of the electro-depletion device (4-2) via a pipeline; the sulfuric acid concentration device (4-1) has an internal heat exchange jacket, the high-temperature medium inlet of the heat exchange jacket is connected to the high-temperature medium outlet of the solar furnace (2-5) via a pipeline; the low-temperature medium outlet of the heat exchange jacket is connected to the low-temperature medium inlet of the solar furnace (2-5) via a pipeline; the anode of the electro-depletion device (4-2) is connected to the positive electrode of green electricity via a conductive copper beam; the cathode of the electro-depletion device (4-2) is connected to the negative electrode of green electricity via a conductive copper beam; the anode outlet of the electro-depletion device (4-2) is connected to the oxygen product pipeline; the cathode outlet of the electro-depletion device (4-2) is connected to the hydrogen product pipeline; the cathode of the electro-depletion device (4-2) is designed with an open outlet, and pure iron is the final product. The outlet of the titanium liquid purification device (5-1) is connected to the inlet of the fine-particle hydrolysis device (5-2) and the coarse-particle hydrolysis device (6-1) via a pipeline; the outlet of the fine-particle hydrolysis device (5-2) is connected to the inlet of the fine-particle fluidized bed calcination device (5-3) via a pipeline; the outlet of the fine-particle fluidized bed calcination device (5-3) is connected to the inlet of the surface modification treatment device (5-4) via a pipeline; and the outlet of the surface modification treatment device (5-4) is connected to the sulfuric acid process titanium dioxide product pipeline. The outlet of the coarse-grained hydrolysis device (6-1) is connected to the inlet of the coarse-grained fluidized bed calcination device (6-2) via a pipeline; the outlet of the coarse-grained fluidized bed calcination device (6-2) is connected to the inlet of the fluidized bed chlorination device (6-3) via a pipeline; the inlet of the fluidized bed chlorination device (6-3) is connected to the chlorine and carbon powder ports via a pipeline; the outlet of the fluidized bed chlorination device (6-3) is connected to the inlet of the magnesiac reduction device (6-4) via a pipeline; the inlet of the magnesiac reduction device (6-4) is connected to magnesium ingots via a pipeline; and the outlet of the magnesiac reduction device (6-4) is connected to high-end sponge titanium products via a pipeline.

2. A method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite based on the system described in claim 1, comprising the following steps: Ilmenite reacts with concentrated sulfuric acid from the sulfuric acid concentration unit (4-1) and the sulfuric acid solution main in the acidolysis unit (1-1) to produce black titanium solution. The heat of the acidolysis unit (1-1) is provided by the high-temperature medium circulation of the solar furnace. The black titanium solution passes through the titanium-iron separation unit (1-2) to obtain iron salt crystals and titanium oxysulfate solution. The titanium oxysulfate solution is sent to the titanium solution purification unit (5-1). The iron salt crystals enter the dissolution and filtration unit (2-1). Iron salt crystals, reclaimed water, and sulfur dioxide are fed into a dissolving and filtering device (2-1) to obtain an acid hydrolysis solution and a dissolving residue. The acid hydrolysis solution is then passed through an iron liquid purification device (2-4) to obtain an iron salt solution and a purification residue. The iron salt solution is then fed into the cathode chamber of the electrometallurgical device (3-1) via a cathode liquid heat exchange device (3-2). The dissolving residue, purification residue, and hydrogen are fed into a high-temperature desulfurization device (2-3) to obtain high-temperature sulfur dioxide and cement clinker. The cement clinker is discharged for further treatment. The hydrogen is a byproduct of the cathode reaction in the electrometallurgical device (3-1) and the electro-depletion device (4-2). A solar furnace (2-5) converts solar energy into thermal energy and provides heat for the high-temperature desulfurization device (2-3) process through a high-temperature medium circulation. High-temperature sulfur dioxide and air exchange heat through a sulfur dioxide heat exchanger (2-2) to obtain low-temperature sulfur dioxide and high-temperature air. The high-temperature air is then fed into the cathode liquid heat exchange device (3-2) and the anolyte heat exchange device (3-3) to heat the cathode liquid and anolyte, respectively. The iron salt solution undergoes an electroreduction reaction in the cathode chamber of the electrometallurgical device (3-1) to obtain pure iron, a low-concentration iron salt solution, and hydrogen as a byproduct. The pure iron is the final product, the low-concentration iron salt solution is sent to the cathode chamber of the electro-depletion device (4-2), part of the hydrogen is sent to the high-temperature desulfurization process, and the remainder is collected as hydrogen product. The dilute sulfuric acid solution from the cathode chamber of the electro-depletion device (4-2) is preheated by the anolyte heat exchanger (3-3) and then introduced into the anode chamber of the electrometallurgical device (3-1) to undergo an electro-oxidation reaction, producing sulfuric acid and oxygen. The sulfuric acid solution is sent to the electro-depletion device (4-2), and the oxygen is collected as a product. The anode in the electrometallurgical device (3-1) is connected to the positive terminal of the DC power supply through a conductive copper beam. The cathode in the electrometallurgical device (3-1) is connected to the negative terminal of the DC power supply through a conductive copper beam. In the cathode chamber of the electro-depletion unit (4-2), a dilute ferrous sulfate solution undergoes an electro-reduction reaction to produce a dilute sulfuric acid solution, pure iron, and hydrogen as a byproduct. Part of the hydrogen is sent to the high-temperature desulfurization process, and the remainder is collected as a hydrogen product. In the anode chamber of the electro-depletion unit (4-2), an electro-oxidation reaction occurs to produce sulfuric acid and oxygen products. The sulfuric acid solution is sent to the sulfuric acid concentration unit (4-1) to obtain regenerated water and concentrated sulfuric acid. The high-temperature medium circulation of the solar furnace provides heat for the sulfuric acid concentration unit (4-1). Titanium oxysulfate is purified by a titanium liquid purification device (5-1) to obtain a purified titanium oxysulfate solution; part of the purified titanium oxysulfate solution is sent to a fine-particle hydrolysis device (5-2) to obtain fine-particle metatitanic acid; the fine-particle metatitanic acid is sent to a fine-particle fluidized bed calcination device (5-3) to obtain the calcined product; the calcined product is sent to a surface modification treatment device (5-4) to obtain the sulfuric acid process titanium dioxide product. After partial purification, the titanium oxysulfate solution is sent to a coarse-grained hydrolysis unit (6-1) to obtain coarse-grained metatitanic acid; the coarse-grained metatitanic acid is sent to a coarse-grained fluidized bed calcination unit (6-2) to obtain coarse-grained titanium dioxide; the coarse-grained titanium dioxide, chlorine gas, and carbon powder are sent to a fluidized bed chlorination unit (6-3) to obtain titanium tetrachloride; titanium tetrachloride and magnesium ingots are sent to a magnesothermic reduction unit (6-4) to obtain high-end sponge titanium products.

3. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, In the iron salt dissolution filtration device (2-1), sulfur dioxide is used to reduce ferric ions, thereby controlling the valence state and promoting dissolution.

4. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, Electrometallurgy uses electrical energy to reduce iron, resulting in no carbon dioxide emissions; The concentration of iron ions is reduced by using an electro-depletion method to achieve water recycling.

5. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, The iron oxide powder process employs fine-particle fluidized bed calcination at a temperature of 300-800 ℃ and a residence time of 5-30 min.

6. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, The high-end sponge titanium process uses coarse-grained crystallization hydrolysis to obtain high-purity coarse-grained metatitanic acid with a particle size greater than 100 micrometers and a purity greater than 95%. The high-end sponge titanium has a purity greater than 99%.

7. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, The heat for the acidolysis unit, sulfuric acid concentration unit, and high-temperature desulfurization unit is provided by the circulating medium of the solar furnace.

8. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, In the electrometallurgical device (3-1), the diaphragm material is an ion-exchange membrane or a porous membrane, wherein the permeation rate of the porous membrane is 1%-40% and the current density is 100 A / m. 2 - 2000 A / m 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, and the cathode is made of iron, copper, titanium or stainless steel. The reaction temperature is 60 ℃-100 ℃, the current efficiency is above 95%, the cathode iron purity is above 99%, and the DC power consumption per ton of iron is less than 3500 kWh.

9. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, The high-temperature desulfurization device (2-3) adopts a fluidized bed or rotary kiln reactor, with a reaction temperature of 1000 ℃-1500 ℃ and a desulfurization rate of over 99%.

10. The method for simultaneously producing low-carbon pure iron, titanium dioxide, and high-end sponge titanium from ilmenite according to claim 2, characterized in that, In the aforementioned electrolytic depletion device (4-2), the diaphragm material is an ion-exchange membrane or a porous membrane, wherein the permeation rate of the porous membrane is 1%-40%, and the current density is 50 A / m. 2 - 1000 A / m 2 The anode is a lead alloy or titanium-based ruthenium-iridium-tantalum coated electrode, and the cathode is made of iron or titanium. The temperature range is 20 ℃ to 100 ℃.

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