Method for preparing titanium-rich material by boiling chlorination of vanadium-titanium magnetite concentrate

Abstract

This invention provides a method for preparing fluidized bed chlorination titanium-rich feedstock from vanadium-titanium magnetite concentrate, comprising: mixing vanadium-titanium magnetite concentrate with a calcifying agent to prepare alkaline green pellets of vanadium-titanium magnetite concentrate, followed by calcification and oxidation roasting to obtain calcified oxide pellets; reducing the calcified oxide pellets with a reducing agent to obtain metallized pellets; melting and separating the metallized pellets with a supplementary calcifying agent to obtain molten iron and molten titanium slag; mixing the molten titanium slag with a water-quenching solution for water quenching to obtain water-quenched modified titanium slag; controlling the particle size of the water-quenched modified titanium slag to obtain fluidized bed titanium slag that meets the particle size requirements of the fluidized bed chlorination process; acid leaching and solid-liquid separation of the fluidized bed titanium slag to obtain titanium-rich feedstock; and alkaline leaching and solid-liquid separation of the titanium-rich feedstock to obtain fluidized bed chlorination titanium-rich feedstock. This invention improves the comprehensive utilization rate of vanadium and titanium in vanadium-titanium magnetite concentrate and prepares titanium into high-quality titanium-rich feedstock suitable for the fluidized bed chlorination process, while also possessing advantages such as industrial operability and environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and more specifically, to a method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate. Background Technology

[0002] Vanadium-titanium magnetite is a major and distinctive polymetallic mineral resource in my country, with enormous reserves. It is characterized by the symbiotic relationship between vanadium, titanium, iron, chromium, and other metals, making its comprehensive utilization value very high. my country's proven reserves exceed 10 billion tons, with potential reserves exceeding 30 billion tons, mainly distributed in the Panxi region of Sichuan, Chengde in Hebei, and Chaoyang in Liaoning. The Panxi region is the richest in vanadium and titanium resources in my country, with proven potential reserves exceeding 10 billion tons and existing reserves of 6.73 billion tons, including 14.75 million tons of vanadium (V₂O₅) and 593 million tons of titanium (TiO₂), accounting for 63% and 90.5% of the national vanadium and titanium reserves, respectively, ranking third and first in the world. The core of research on the comprehensive utilization of vanadium-titanium magnetite concentrate lies in the efficient and synergistic recovery of the three strategic metals: iron, vanadium, and titanium.

[0003] Currently, the mainstream smelting technologies are the traditional blast furnace smelting system and the smelting reduction system. Blast furnace ironmaking remains the mainstream technology in modern ironmaking. Taking Panzhihua Iron and Steel Group as an example, blast furnace smelting of vanadium-titanium magnetite concentrate is mainly for steel production, with vanadium extraction as a secondary goal. The iron recovery rate is about 76%, and the vanadium recovery rate is only about 45%. However, the TiO2 content in the blast furnace slag is about 22% to 25%, which cannot be effectively utilized and is stockpiled. Smelting reduction ironmaking is a non-blast furnace ironmaking technology that uses non-coking coal as energy and lump ore, pellets, or iron ore powder as raw materials. Under high-temperature melting conditions, carbon reduces iron oxides to achieve efficient separation of slag and iron and directly produce liquid iron. Currently, COREX, FINEX, and HIsmelt are the three major mainstream smelting reduction ironmaking processes that have achieved commercial application. However, these mainstream processes have not solved the problem of the rational utilization of titanium slag.

[0004] Titanium slag is characterized by its dense structure, low TiO2 content, and high content of non-ferrous impurities such as Ca, Mg, Al, and Si. Currently, sponge titanium and chloride-process titanium dioxide are the priority development directions for the titanium industry. The high calcium and magnesium impurity content of smelting titanium slag makes it impossible to directly use the efficient and environmentally friendly fluidized bed chlorination process to produce sponge titanium and titanium dioxide. This results in my country's reliance on imports for high-quality titanium raw materials used in the production of sponge titanium and chloride-process titanium dioxide, severely restricting the development of my country's sponge titanium and titanium dioxide industries.

[0005] The preparation of titanium-rich materials is a process of removing impurities and enriching them. Currently, the main methods for preparing titanium-rich materials include acid leaching, reduction-corrosion, and selective chlorination. (1) Using hydrochloric acid leaching can reduce the content of some Fe, Ca, Mg, Al and other elements in titanium slag, so that TiO2 is enriched in the slag. However, there are still a lot of Ca and Mg elements in the dense black titanium phase, and the product powdering phenomenon is serious after acid leaching. Even after pre-oxidation treatment, only some rutile is formed in the titanium slag, and the powdering problem cannot be solved. (2) The limitation of the reduction-corrosion method is that the calcium and magnesium removal capacity is poor. It must use weathered high-grade, low-impurity ilmenite as raw material. The solid phase reduction requires high temperature and high technical difficulty. Therefore, this technology is not suitable for removing impurities from titanium slag. (3) Selective chlorination equipment is severely corroded, which is not conducive to environmental protection. Moreover, it has not been industrialized. The calcium and magnesium content in the titanium slag is high, which is not suitable for preparing titanium-rich materials by selective chlorination. Currently, a large number of experimental studies have been conducted on titanium slag obtained from the smelting of Panzhihua titanium ore. The prepared titanium-rich material has a high CaO content and fine particle size, which cannot meet the requirements of ωCaO≤0.15%, ωΣ(CaO+MgO)≤1.5% and particle size for the fluidized bed chlorination process.

[0006] Patent CN118996163A discloses a method for extracting valuable elements from vanadium-titanium magnetite. Specifically, it discloses the use of mineral processing methods to separate vanadium-titanium chromite concentrate from vanadium-titanium magnetite. Under controlled reduction conditions, an electric furnace smelting method is used to reduce Fe in the vanadium-titanium chromite concentrate to produce molten iron, while V2O5, TiO2, Cr2O3, etc. remain in the smelting slag. Then, the smelting slag is mixed with strong acid for acid hydrolysis to obtain an acid hydrolysis solution. The titanium in the acid hydrolysis solution is hydrolyzed to obtain a titanium-containing product and a vanadium-chromium-containing mother liquor. The vanadium-chromium mother liquor is then extracted and back-extracted to obtain a vanadium solution and a chromium solution, respectively.

[0007] Patent CN105671306A discloses a method for separating iron, vanadium, and titanium from vanadium-titanium magnetite. Specifically, it discloses that by controlling the direct reduction temperature of vanadium-titanium magnetite, most of the vanadium is retained in the slag. Through grinding and magnetic separation, iron is introduced into the magnetic material while vanadium and titanium are introduced into the non-magnetic vanadium-titanium slag. After adding sodium salt to the vanadium-titanium slag and calcining it at high temperature, vanadium is extracted by water leaching to obtain vanadium-containing liquid and titanium-rich slag.

[0008] Patent CN102061397A discloses a method for recovering vanadium, chromium, titanium, and iron from vanadium-titanium magnetite. Specifically, it discloses that vanadium-titanium magnetite concentrate is mixed with sodium salt and then oxidatively roasted to convert vanadium and chromium into water-soluble sodium vanadate and sodium chromate. The ore is then leached in water to obtain a vanadium-chromium-containing solution. Vanadium pentoxide and chromium trioxide are separated from the solution. The residue after leaching can be mixed with pulverized coal to form pellets, reduced in a rotary hearth furnace, and magnetically separated to obtain magnetic iron powder, which can be used as a raw material for powder metallurgy or steelmaking, and a non-magnetic product containing more than 50% TiO2, which can be used as a raw material for titanium extraction.

[0009] Patent CN102676796A discloses a method for processing vanadium-titanium magnetite. Specifically, it discloses a method for preparing iron powder and titanium concentrate by co-fluidized roasting and magnetic separation of vanadium-titanium magnetite with additives CaO, CaCO3, CaCl2, and CaF2. The raw vanadium-titanium magnetite is crushed and ground into powder, then dried and preheated with additives. The hot ore is then reduced and roasted in a fluidized bed furnace, and after water quenching, it is ball-milled and magnetically separated to obtain iron powder and titanium concentrate.

[0010] Patent CN110656237A discloses a process for direct vanadium extraction using a vanadium-titanium magnetite tunnel kiln. Specifically, it discloses that vanadium-titanium magnetite powder, sodium salt, alkali, anthracite, and binder are made into pellets. The pellets are loaded into a material basket with multiple vent holes. The full material baskets are stacked in a kiln car and oxidized and roasted using a vanadium-titanium magnetite tunnel kiln. Then, the kiln cars loaded with material are sequentially fed into the preheating section inlet, and the pellets in the material baskets are ignited. The material in the kiln car is preheated in the preheating section. The kiln cars are then sequentially transferred to the heating section via a transfer car. The vanadium-titanium iron raw material in the kiln car undergoes a vanadium extraction reaction in the heating section at high temperature formed by the combustion of anthracite. After the reaction, the kiln car is sent out from the cooling section outlet, where vanadium is leached with water and then calcined to obtain flake vanadium.

[0011] In summary, existing research on the comprehensive utilization of vanadium-titanium magnetite has not addressed the preparation of titanium-rich materials from vanadium-titanium magnetite concentrate that meet the requirements of the fluidized bed chlorination process. Therefore, this invention is proposed. Summary of the Invention

[0012] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing fluidized bed chlorination titanium-rich materials from vanadium-titanium magnetite concentrate. This method improves the comprehensive utilization rate of vanadium and titanium in vanadium-titanium magnetite concentrate and prepares titanium into high-quality titanium-rich materials suitable for fluidized bed chlorination processes. It also has advantages such as industrial operability and environmental friendliness.

[0013] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A method for preparing hydrated titanium-rich feedstock from vanadium-titanium magnetite concentrate includes the following steps: Step 1: Mix vanadium-titanium magnetite concentrate with a calcifying agent to prepare alkaline green pellets of vanadium-titanium magnetite concentrate. Then, calcify and oxidize the alkaline green pellets to obtain calcified oxide pellets. Step 2: Mix the calcified oxide pellets with a reducing agent and reduce them at high temperature to reduce Fe2O3 in the calcified oxide pellets to metallic iron, thereby obtaining metallized pellets; Step 3: After melting and separating the metallized pellets with a supplementary calcifying agent, molten iron and molten titanium slag are obtained. The molten titanium slag is mixed with water quenching liquid and water quenched, and then rapidly cooled and granulated to obtain water-quenched modified titanium slag. Step 4: Control the particle size of the water-quenched modified titanium slag to obtain fluidized bed titanium slag that meets the particle size requirements of the fluidized bed chlorination process. Step 5: Acid leaching and solid-liquid separation are performed on the boiling titanium slag to obtain titanium-rich material; Step 6: The titanium-rich material is subjected to alkaline leaching and solid-liquid separation to obtain boiling chlorinated titanium-rich material.

[0014] Furthermore, the diameter of the alkaline green pellets described in step 1 is 9~16mm.

[0015] Further, the composition of the vanadium-titanium magnetite concentrate mentioned in step 1, by mass percentage, includes TFe 50~60%, TiO2 8~15%, V2O5 0.5~2.0%, SiO2 0.5~5.0%, and CaO 0.1~5%.

[0016] Further, the calcifying agent in step 1 is at least one of a calcium-containing compound or a calcium-containing mineral; the calcium-containing compound is at least one of CaO, CaSO4, and Ca(OH)2.

[0017] Furthermore, in step 1, during the alkaline pelletizing of vanadium-titanium magnetite concentrate, the amount of calcifying agent added is 1.2 to 2.5 parts relative to 100 parts of vanadium-titanium magnetite concentrate.

[0018] Furthermore, in step 1, the calcination oxidation calcination temperature is 1150~1250℃, and the calcination time is 20min~10h.

[0019] Furthermore, the compressive strength of the calcified oxide pellets described in step 1 is ≥1500N / pellet.

[0020] Furthermore, the total amount of calcifying agent added in step 1 and the supplementary calcifying agent added in step 3 is calculated as follows: relative to 100 parts of vanadium-titanium magnetite concentrate, the total amount of calcifying agent added in step 1 and the supplementary calcifying agent added in step 3 is calculated using the following formula: Wt Ca(OH)2 =K(123Wt SiO2 +41Wt V2O5 -132Wt CaO ), Among them Wt Ca(OH)2 The percentage of the total amount of calcifying agent added, with an excess coefficient K of 1~1.3, Wt SiO2 Wt V2O5 and Wt CaO The percentage contents of SiO2, V2O5 and CaO in titanoma magnetite concentrate are respectively. And the total amount of calcifying agent added (Wt) Ca(OH)2 Not less than 1.2 portions.

[0021] Furthermore, in step 2, the mass ratio of the calcified oxide pellets to the reducing agent is 1:0.1 to 1:2.

[0022] Furthermore, the reducing agent mentioned in step 2 is at least one of carbon-based substances, hydrogen, and CO.

[0023] Furthermore, in step 2, the reduction temperature is 900~1300℃, and the reduction time is 30min~20h.

[0024] Furthermore, the metallization rate of the metallized pellets after reduction in step 2 is ≥90%.

[0025] Furthermore, the melting temperature in step 3 is 1400~1650℃.

[0026] Further, the water quenching solution in step 3 is at least one of water, acidic wastewater, ferrous chloride solution, and alkaline solution; the alkaline solution is at least one of sodium hydroxide solution, calcium hydroxide solution, and potassium hydroxide solution.

[0027] Furthermore, the water quenching pressure in step 3 is 1~40 kg·f / cm². 2 .

[0028] Furthermore, the particle size D of the water-quenched modified titanium slag described in step 3 is... 50 =0.1~4mm.

[0029] Furthermore, in step 4, particle size control involves crushing, grinding, screening, and classifying the water-quenched modified titanium slag to obtain hydrated titanium slag that meets the particle size requirements of the hydrated chlorination process.

[0030] Furthermore, step 4 yields a fluidized bed titanium slag with a particle size range of 40-160 mesh, which is a water-quenched modified titanium slag and meets the particle size requirements of the fluidized bed chlorination process.

[0031] Furthermore, in step 5, the acid leaching is performed using a hydrochloric acid leaching solution, in which the boiling titanium slag is leached with the hydrochloric acid leaching solution.

[0032] Furthermore, in step 5, acid leaching is carried out by high-temperature and high-pressure leaching to obtain leached slurry. The leaching temperature is 110~180℃, the pressure corresponds to the vapor pressure of the hydrochloric acid leaching solution at the leaching temperature, the leaching liquid-solid ratio is 1:1~10:1 ml / g, and the leaching time is 1~6h.

[0033] Furthermore, in step 5, the titanium yield during the acid leaching process is ≥99%, the vanadium leaching rate is ≥90%, the chromium leaching rate is ≥50%, the calcium leaching rate is ≥95%, the magnesium leaching rate is ≥93%, and the pulverization rate of the fluidized bed titanium slag after acid leaching is ≤0.5% of the -96μm size.

[0034] Furthermore, in step 5, the solid-liquid separation also yields a hydrochloric acid leaching solution.

[0035] Furthermore, the hydrochloric acid leaching solution comprises hydrochloric acid, chloride salt, and oxidizing agent.

[0036] Furthermore, the concentration of the hydrochloric acid solution is 15-25 wt%.

[0037] Further, the chloride salt is at least one selected from FeCl3, FeCl2, AlCl3, MgCl2, and CaCl2, and the chloride salt content is 0.1~1.5 mol / L.

[0038] Further, the oxidant is at least one selected from FeCl3, O2, NaClO, H2O2, Cl2, and KMnO4, and the content of the oxidant is 0.1~3.0 mol / L, or the partial pressure of the oxidant is 0.1~1 MPa.

[0039] Furthermore, the hydrochloric acid leaching solution is spray-fired at a high temperature to generate oxide solids and hydrochloric acid gas. The spray-fire temperature is 550~750℃. The hydrochloric acid gas is then absorbed by water spraying in a multi-stage countercurrent to generate a regenerated hydrochloric acid solution with a concentration of 18~22wt%. The regenerated hydrochloric acid solution is returned to the acid leaching process.

[0040] Further, in step 6, the titanium-rich material is placed in an alkaline leaching solution and heated under normal pressure to remove silicon. The leaching temperature is 40~100℃, the leaching liquid-to-solid ratio is 0.5:1~20:1ml / g, and the leaching time is 1~6h.

[0041] Further, the alkaline leaching solution in step 6 is at least one of sodium hydroxide, potassium hydroxide, or lithium hydroxide, and the concentration of the alkaline leaching solution is 5-80 wt%.

[0042] Furthermore, the composition of the boiling chlorinated titanium-rich material obtained in step 6, by mass percentage, includes TFe≤2.0%, TiO2≥85.00%, SiO2≤1.00%, MgO≤1.35%, CaO≤0.15%, and ωΣ(CaO+MgO)≤1.50%.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention relates to a method for preparing molten titanium-rich chlorinated material from vanadium-titanium magnetite concentrate. The method involves alkaline green pelletizing of vanadium-titanium magnetite concentrate, reduction, melting and separation, water quenching modification of titanium slag, and stepwise impurity removal through acid and alkaline leaching. By preparing high-performance alkaline green pellets of vanadium-titanium magnetite, the particle size of the raw material is increased, improving the adaptability of the raw material reduction and melting and separation. Furthermore, a calcifying agent can be added to change the mineral phase during water quenching, which is beneficial for the acid and alkaline leaching of impurities.

[0044] 2. The pig iron produced after melting and separation in this invention has high purity and can be used as a high-quality raw material for steelmaking, thus having great economic value.

[0045] 3. The titanium slag of this invention is directly granulated after water quenching modification, and the particle size meets the requirements of subsequent acid leaching for impurity removal and fluidized bed chlorination raw materials; after modification, impurities such as calcium, magnesium and silicon are more easily leached out.

[0046] 4. This invention enables acid recycling, which greatly reduces production energy consumption and reduces emissions of waste gas, wastewater, and solid waste.

[0047] 5. This invention constructs a chloride-oxidant hydrochloric acid leaching system, which increases the impurity removal rate and solves the problems of high titanium dissolution rate and high pulverization rate in the acid leaching impurity removal process.

[0048] 6. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate of the present invention is applicable not only to vanadium-titanium magnetite concentrate with low vanadium-titanium and high iron content, but also to vanadium-titanium magnetite concentrate with high vanadium-titanium and low iron content. Attached Figure Description

[0049] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0050] Figure 1 This is a process flow diagram of the method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to the present invention. Figure 2 XRD pattern of water-quenched modified titanium slag prepared in Example 3 of the present invention. Detailed Implementation

[0051] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0052] A method for preparing hydrated titanium-rich feedstock from vanadium-titanium magnetite concentrate includes the following steps: Step 1: Using vanadium-titanium magnetite concentrate and calcifying agent as raw materials, mix vanadium-titanium magnetite concentrate and calcifying agent to prepare alkaline green pellets of vanadium-titanium magnetite concentrate. Then, calcify and oxidize the alkaline green pellets to change the phase composition and improve the pellet strength to obtain calcified oxidized pellets. Step 2: Mix the calcified oxide pellets with a reducing agent and reduce them at high temperature to reduce Fe2O3 in the calcified oxide pellets to metallic iron, thereby obtaining metallized pellets; Step 3: Add the metallized pellets and the supplementary calcifying agent to the melting furnace, and after melting, molten iron and molten titanium slag are obtained. Mix the molten titanium slag with water quenching liquid and water quench it. Then, rapidly cool and granulate it to obtain water-quenched modified titanium slag. Step 4: Control the particle size of the water-quenched modified titanium slag to obtain fluidized bed titanium slag that meets the particle size requirements of the fluidized bed chlorination process. Step 5: Acid leaching of the boiling titanium slag, high-temperature and pressure leaching of the boiling titanium slag with hydrochloric acid leaching solution to remove impurities and obtain leaching slurry, solid-liquid separation and washing of the leaching slurry to obtain hydrochloric acid leaching solution and filter cake, and drying of filter cake to obtain titanium-rich material. Step 6: Alkali leaching of the titanium-rich material. The titanium-rich material is placed in an alkaline leaching solution and heated at normal pressure to remove silicon. After alkali leaching, the leaching slurry is subjected to solid-liquid separation to obtain an alkaline leaching solution and a filter cake. The filter cake is dried to obtain boiling chlorinated titanium-rich material.

[0053] Preferably, the diameter of the alkaline green pellets in step 1 is 9~16mm, including but not limited to 9mm, 10mm, 12mm, 15mm, and 16mm.

[0054] Preferably, in step 1, the vanadium-titanium magnetite concentrate is dried and the moisture content is adjusted by a dryer, and then ground and mixed with a calcifying agent in a roller mill or a grinding mill. After adjusting the moisture content, alkaline green pellets of vanadium-titanium magnetite concentrate are prepared in a disc pelletizer. The alkaline green pellets are screened by 16mm and 9mm roller screens to obtain qualified alkaline green pellets of 9-16mm.

[0055] Preferably, the composition of the vanadium-titanium magnetite concentrate in step 1, by mass percentage, includes 50-60% TFe, 8-15% TiO2, 0.5-2.0% V2O5, 0.5-5.0% SiO2, 0.1-5% CaO, and other impurities.

[0056] Preferably, the calcifying agent in step 1 is at least one of CaO, CaSO4, Ca(OH)2 calcium-containing compounds or calcium-containing minerals; preferably Ca(OH)2, which is both a calcifying agent and a ball-forming binder. Ca(OH)2 is dry slaked lime, which is slaked lime produced from CaO using a dry slaking process, wherein CaO ≥ 70% and the particle size is between 1 and 100 μm.

[0057] Preferably, in step 1, during the alkaline pelletizing of vanadium-titanium magnetite concentrate, the amount of the calcifying agent, such as Ca(OH)2, added is 1.2 to 2.5 parts relative to 100 parts of vanadium-titanium magnetite concentrate, more preferably 1.2 to 2.0 parts.

[0058] In the preparation of alkaline green pellets from vanadium-titanium magnetite concentrate, a calcifying agent such as Ca(OH)2 is added as a binder to prepare alkaline pellets. Ca(OH)2 replaces the bentonite binder used in conventional pelletizing processes, avoiding the introduction of SiO2 and Al2O3 into the pellets and reducing the pressure of acid leaching for aluminum removal and alkaline leaching for silicon removal. By adding the calcifying agent Ca(OH)2 to change the basicity of the pellets, in subsequent calcification roasting, melting, and water quenching processes, elements Si and V combine with CaO, altering the mineral phase composition of the Si and V water-quenched slag. The slag is dominated by Ca-Si silicate phase and CaV2O6, which is beneficial for the subsequent acid and alkaline leaching of elements such as aluminum, calcium, magnesium, vanadium, and silicon.

[0059] Preferably, the total amount of calcifying agent added in step 1 and the supplementary calcifying agent added in step 3 is calculated as follows: relative to 100 parts of vanadium-titanium magnetite concentrate, the total amount of calcifying agent added in step 1 and the supplementary calcifying agent added in step 3 is calculated using the following formula: Wt Ca(OH)2 =K(123Wt SiO2 +41Wt V2O5 -132Wt CaO ), where Wt Ca(OH)2 The proportion of the total amount of calcifying agent such as Ca(OH)2 added, with an excess coefficient K of 1~1.3, Wt SiO2 Wt V2O5 and Wt CaO The percentage contents of SiO2, V2O5, and CaO in titania magnetite concentrate are respectively; and the total amount of calcifying agent added (Wt) is also included. Ca(OH)2 Not less than 1.2 parts. When the theoretically calculated total amount added exceeds the amount of calcifying agent added in step 1 (1.2~2.5 parts, preferably 1.2~2.0 parts), the supplementary calcifying agent is added to the melting furnace along with the metallized pellets in the melting stage of step 3.

[0060] One of the main functions of adding calcining agents such as Ca(OH)2 is that during the calcination, oxidation, and roasting process, calcining agents such as Ca(OH)2 react with SiO2 and V2O5 in vanadium-titanium magnetite concentrate to generate compounds such as CaSiO3 and calcium vanadate (such as CaV2O6) that can be dissolved by acid. This is beneficial for leaching impurities such as calcium and vanadium from titanium-containing materials, and at the same time, it is beneficial for removing silicon during alkaline leaching of titanium-rich materials to produce high-grade boiling chlorinated titanium-rich materials. The second main function of adding calcifying agents such as Ca(OH)2 is as a binder in pellet preparation. The amount of calcifying agent such as Ca(OH)2 added is related to the content of SiO2, V2O5, and CaO in the vanadium-titanium magnetite concentrate. When the content of SiO2 and V2O5 is low or the content of CaO is high, the amount of calcifying agent such as Ca(OH)2 added according to the calculation formula may be low and may not meet the requirements of the binder for pellet preparation. In order to ensure the preparation of alkaline green pellets, the minimum amount of calcifying agent such as Ca(OH)2 added is 1.2 parts. The range of calcifying agent such as Ca(OH)2 added during alkaline green pelletizing is 1.2~2.5 parts. When the theoretically calculated total amount added exceeds this range, the excess amount is added as supplementary calcifying agent in the melting stage of step 3 along with the metallized pellets into the melting furnace.

[0061] Preferably, the calcination temperature in step 1 is 1150~1250℃ (including but not limited to 1150℃, 1200℃, 1250℃), more preferably 1200~1250℃, and the calcination time is 20min~10h (including but not limited to 20min, 30min, 1h, 2h, 3h, 5h, 6h, 8h, 10h), more preferably 2~6h, and the compressive strength of the calcined oxidized pellets after calcination is ≥1500N / piece.

[0062] Preferably, the mass ratio of the calcified oxide pellets to the reducing agent in step 2 is 1:0.1 to 1:2 (including but not limited to 1:0.1, 1:0.5, 1:1, 1:1.5, and 1:2).

[0063] Preferably, the reducing agent in step 2 is at least one of carbon-based substances (such as coal, coke, etc.), hydrogen, and CO, and the reduction method includes, but is not limited to, CO reduction, H2 reduction, and carbon-based (coal, coke) reduction.

[0064] Preferably, the reduction temperature in step 2 is 900~1300℃ (including but not limited to 900℃, 1000℃, 1100℃, 1200℃, 1300℃), more preferably 1200~1250℃, and the reduction time is 30min~20h (including but not limited to 30min, 1h, 2h, 3h, 5h, 6h, 8h, 10h), and the metallization rate of the metallized pellets after reduction is ≥90%.

[0065] Preferably, the melting temperature in step 3 is 1400~1650℃ (including but not limited to 1400℃, 1450℃, 1500℃, 1550℃, 1600℃, 1650℃).

[0066] Preferably, the water quenching solution in step 3 is at least one of water, acidic wastewater, ferrous chloride solution, and alkaline solution; the alkaline solution is at least one of sodium hydroxide solution, calcium hydroxide solution, and potassium hydroxide solution.

[0067] Preferably, the water quenching pressure in step 3 is 1~40 kg·f / cm. 2 (including but not limited to 1 kg·f / cm) 2 5kg·f / cm 2 10 kg·f / cm 2 20kg·f / cm 2 30kg·f / cm 2 40 kg·f / cm 2 The particle size D of the water-quenched modified titanium slag. 50 = 0.1~4mm (including but not limited to 0.1mm, 0.5mm, 1mm, 2mm, 3mm, 4mm).

[0068] The molten titanium slag is rapidly cooled by water quenching. After melting and separation, the titanium in the resulting molten titanium slag mainly exists as magnesium-containing black titanium stone and a small amount of rutile minerals. In the water-quenched modified titanium slag, all calcium and some magnesium are distributed as incompletely crystalline Ca(Mg)-Si silicate phases interspersed within the magnesium-containing black titanium stone phase, while in conventional titanium slag, the main components are well-crystalline Ca(Mg)-Al-Si aluminosilicate phases interspersed within the black titanium stone phase. Simultaneously, the molten titanium slag is directly granulated after quenching modification. The particle size distribution of the water-quenched modified titanium slag obtained by this invention is shown in Table 1 compared to the particle size distribution obtained by the traditional crushing process. Table 1. Particle size distribution of water-quenched modified titanium slag obtained by water quenching granulation according to the present invention and the particle size distribution of traditional crushing process.

[0069] Table 1 shows the particle size composition of the water-quenched modified titanium slag obtained by water quenching granulation of the present invention and the particle size composition of the traditional crushing process. It can be seen that the proportion of qualified particle size (0.096~0.9mm, i.e. 20~160 mesh) of the water-quenched modified titanium slag obtained by water quenching granulation of the present invention that meets the requirements of boiling chlorination is increased from 80% in the traditional crushing process to more than 95%, and the crushing efficiency is increased by 4~5 times.

[0070] Preferably, step 4, particle size control, involves crushing, grinding, screening, and classifying the water-quenched modified titanium slag to obtain fluidized bed titanium slag that meets the particle size requirements of the fluidized bed chlorination process.

[0071] Preferably, in step 4, the crushing and grinding of the water-quenched modified titanium slag is carried out using at least one of the conventional crushing and grinding methods such as roller crushing, hammer crushing, rod milling or ball milling; the screening and grading is carried out using at least one of the conventional particle size classification methods such as vibrating screen or air classifier; the boiling titanium slag obtained in step 4 is water-quenched modified titanium slag with a particle size range of 40~160 mesh, which meets the particle size requirements of the boiling chlorination process.

[0072] Preferably, in step 5, the acid leaching uses a hydrochloric acid leaching solution to leach the boiling titanium slag with the hydrochloric acid leaching solution. The hydrochloric acid leaching solution comprises hydrochloric acid, a chloride, and an oxidizing agent, and is prepared by adding a chloride and an oxidizing agent to a hydrochloric acid solution. The concentration of the hydrochloric acid solution is 15-25 wt%; the chloride is at least one selected from FeCl3, FeCl2, AlCl3, MgCl2, and CaCl2, and the chloride content is 0.1-1.5 mol / L (including but not limited to 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 1 mol / L, 1.2 mol / L, and 1.5 mol / L); the oxidizing agent is at least one selected from FeCl3, O2, NaClO, H2O2, Cl2, and KMnO4. The content of the oxidant (when at least one of O4 is selected) is 0.1~3.0 mol / L (including but not limited to 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 1 mol / L, 1.2 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L), or the partial pressure of the oxidant (when at least one of O2 and Cl2 is selected) is 0.1~1 MPa (0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa).

[0073] The addition of chloride salts enhances the activity of hydrogen ions in hydrochloric acid, which is beneficial for the leaching of impurities such as Fe, Al, Ca, Mg, and Mn from titanium-containing materials. Simultaneously, the addition of chloride salts increases the ionic strength of the leaching solution, which is beneficial for the hydrolysis of metatitanic acid, thus increasing titanium recovery and improving the filtration performance of the leaching slurry. Oxidants are used to oxidize trivalent titanium to tetravalent titanium and trivalent vanadium to tetravalent or pentavalent vanadium during the leaching process, which is beneficial for increasing titanium recovery and improving vanadium leaching rate.

[0074] This invention constructs a chloride-oxidant hydrochloric acid leaching system. Adding chloride increases the chloride ion activity in the hydrochloric acid leaching system, which is beneficial for impurity leaching; however, the leaching process easily leads to the pulverization of titanium-rich materials, resulting in a low product yield. Based on this, an oxidant is added to further improve the leaching process. 3+ In-situ oxidation to Ti 4+The titanium slag is hydrolyzed to form metatitanic acid, which is adsorbed inside the particles, solving the problem of high titanium pulverization during acid leaching. The pulverization rate (-96µm proportion) is less than 0.5%, meeting the requirements of the fluidized bed chlorination process. Simultaneously, the addition of an oxidant effectively improves the leaching rate of V. Before leaching, V in the water-quenched modified titanium slag mainly exists in the +3 valence state, which is closely related to the reduction treatment; however, after leaching, V mainly exists in the +4 valence state, indicating that its valence state tends to be a stable high oxidation state. Vanadium tetravalent has high solubility in hydrochloric acid solution, thus improving the leaching rate of V in the modified titanium slag. Furthermore, under high acidity conditions, as the concentrations of vanadium tetravalent and titanium trivalent increase and the oxidant concentration decreases, vanadium tetravalent will further oxidize Ti. 3+ Ti 4+ This is beneficial to Ti 4+ Hydrolysis and improved titanium recovery rate.

[0075] Preferably, in step 5, acid leaching is carried out by high-temperature and high-pressure leaching to obtain leaching slurry. The leaching temperature is 110~180℃ (including but not limited to 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃), the pressure corresponds to the vapor pressure of the hydrochloric acid leaching solution at the leaching temperature, the leaching liquid-solid ratio is 1:1~10:1ml / g (including but not limited to 1:1ml / g, 3:1ml / g, 5:1ml / g, 6:1ml / g, 8:1ml / g, 10:1ml / g), and the leaching time is 1~6h (including but not limited to 1h, 2h, 3h, 4h, 5h, 6h).

[0076] Preferably, the leachate slurry in step 5 is subjected to solid-liquid separation using conventional solid-liquid separation methods such as pressure filtration and centrifugation, with membrane pressure filtration being preferred. After pressure filtration, the filter cake is washed with water, and the filtrate is a hydrochloric acid leachate solution. The filter cake is used as titanium-rich material, or the filter cake is dried to obtain titanium-rich material at a drying temperature ≤350℃.

[0077] Preferably, in step 5, the titanium yield during acid leaching is ≥99%, the vanadium leaching rate is ≥90%, the chromium leaching rate is ≥50%, the calcium leaching rate is ≥95%, the magnesium leaching rate is ≥93%, and the pulverization rate (-96μm percentage) of the fluidized bed titanium slag after acid leaching is ≤0.5%.

[0078] Preferably, in step 5, the hydrochloric acid leaching solution is spray-fired at a high temperature to generate oxide solids and hydrochloric acid gas. The spray-fire temperature is 550~750℃ (including but not limited to 550℃, 600℃, 650℃, 700℃, and 750℃). The hydrochloric acid gas is then subjected to multi-stage countercurrent absorption via water spraying to generate a regenerated hydrochloric acid solution with a concentration of 18~22wt%. The regenerated hydrochloric acid solution is returned to the acid leaching process. During the incineration process, metal chlorides such as FeCl2, MgCl2, Fe2Cl3, VOCl2, VOCl, and AlCl3 in the hydrochloric acid leaching solution are converted into metal oxides MgO, Fe2O3, V2O5, and Al2O3. However, CaCl2 remains unchanged during incineration due to its high hydrolysis temperature and continues to exist in the form of CaCl2.

[0079] Preferably, in step 6, the titanium-rich material is placed in an alkaline leaching solution and heated under normal pressure to remove silicon. The leaching temperature is 40~100℃ (including but not limited to 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃), the leaching liquid-solid ratio is 0.5:1~20:1ml / g (including but not limited to 0.5:1ml / g, 1:1ml / g, 2:1ml / g, 5:1ml / g, 6:1ml / g, 8:1ml / g, 10:1ml / g, 15:1ml / g, 20:1ml / g), and the leaching time is 1~6h (including but not limited to 1h, 2h, 3h, 4h, 5h, 6h).

[0080] Preferably, the alkaline leaching solution in step 6 is at least one of sodium hydroxide, potassium hydroxide, or lithium hydroxide, and the concentration of the alkaline leaching solution is 5-80 wt%.

[0081] Preferably, after alkali leaching in step 6, the leachate slurry is subjected to solid-liquid separation using conventional solid-liquid separation methods such as pressure filtration and centrifugation, with diaphragm pressure filtration being preferred. After pressure filtration, the filter cake is washed with water and dried to obtain a boiling titanium-rich chlorinated material with a particle size range of 40-160 mesh.

[0082] Preferably, the composition of the boiling titanium-rich chlorinated material obtained in step 6, by mass percentage, includes TFe≤2.0%, TiO2≥85.00%, SiO2≤1.00%, MgO≤1.35%, CaO≤0.15%, and ωΣ(CaO+MgO)≤1.50%.

[0083] Example 1 In this embodiment, calcified oxide pellets are prepared using vanadium-titanium magnetite concentrate and calcifying agent as raw materials. The vanadium-titanium magnetite concentrate and calcifying agent are mixed to prepare alkaline green pellets of vanadium-titanium magnetite concentrate. The alkaline green pellets are then subjected to calcification oxidation roasting to change the phase composition and improve the pellet strength, thereby obtaining calcified oxide pellets.

[0084] In this embodiment, calcified oxide pellets were prepared. The composition of the vanadium-titanium magnetite concentrate used is shown in Table 2, and the composition of the Ca(OH)2 used is shown in Table 3. The Ca(OH)2 particles are relatively fine, with most particles having a diameter of about 10 μm. The proportion of large particles is low, with -200 mesh accounting for 95%.

[0085] The specific preparation process is as follows: Vanadium-titanium magnetite concentrate and 1.9 parts Ca(OH)₂ (100 parts vanadium-titanium magnetite concentrate) are added and milled to prepare alkaline green pellets. The alkaline green pellets are then calcined and oxidized at 1200℃ for 2 hours to prepare calcified oxide pellets. The physical properties of the vanadium-titanium magnetite concentrate calcified oxide pellets are shown in Table 4, and the chemical composition of the vanadium-titanium magnetite concentrate calcified oxide pellets is shown in Table 5.

[0086] Table 2 Chemical composition of vanadium-titanium magnetite concentrate

[0087] Table 3 Chemical composition of Ca(OH)₂

[0088] Table 4 Physical properties of vanadium-titanium magnetite concentrate calcified oxide pellets

[0089] Table 5 Chemical composition of vanadium-titanium magnetite concentrate calcified oxide pellets

[0090] Example 2 The calcified oxide pellets prepared in Example 1 were mixed with a reducing agent and reduced at high temperature to reduce Fe2O3 in the calcified oxide pellets to metallic iron, thereby obtaining metallized pellets.

[0091] The specific preparation process is as follows: the calcified oxide pellets prepared in Example 1 are mixed with anthracite, the ratio of calcified oxide pellets to anthracite is 1:0.5, the reduction temperature is 1250℃, and the reduction time is 2h to prepare metallized pellets. The chemical composition of the metallized pellets is shown in Table 6, and the metallization rate η of the metallized pellets is 91.59%.

[0092] Table 6 Chemical composition of vanadium-titanium magnetite concentrate metallized pellets

[0093] Example 3 The metallized pellets prepared in Example 2 were added to a melting furnace with a supplementary calcifying agent for melting and separation to obtain molten iron and molten titanium slag. The molten titanium slag was mixed with water quenching liquid and water quenched, then rapidly cooled and granulated to obtain water-quenched modified titanium slag.

[0094] The specific preparation process is as follows: The metallized pellets prepared in Example 2 are fed into a melting furnace for melting at a melting temperature of 1650℃. A supplementary calcifying agent, Ca(OH)2, is added to the furnace, with 0.15 parts Ca(OH)2 added per 100 parts vanadium-titanium magnetite concentrate. Molten iron and molten titanium slag are produced, using a pressure of 20 kg·f / cm². 2 Water-quenched modified titanium slag was prepared by rapidly cooling and granulating molten titanium slag with high-pressure water. The composition of the water-quenched modified titanium slag is shown in Table 7, and its XRD pattern is shown in... Figure 2 As shown in the figure, the phase composition of the water-quenched modified titanium slag is black titanium stone, rutile and calcium silicate compound.

[0095] Table 7. Composition of water-quenched modified titanium slag (wt%)

[0096] Example 4 The water-quenched modified titanium slag prepared in Example 3 was crushed, ground, and screened to obtain fluidized bed titanium slag that met the particle size requirements of the fluidized bed chlorination process. The obtained fluidized bed titanium slag had a particle size range of 60-160 mesh. The 60-160 mesh water-quenched modified titanium slag was then upgraded and impurities were removed using a chloride-oxidant hydrochloric acid leaching system. The reaction conditions were as follows: hydrochloric acid concentration 20wt%, FeCl3 was selected as both oxidant and chloride, with a total FeCl3 content of 0.3mol / L, a leaching liquid-to-solid ratio of 3:1ml / g, a leaching temperature of 145℃, and a leaching time of 2h. After the reaction, the leaching slurry was filtered for solid-liquid separation. The filter cake was washed and dried to obtain titanium-rich material. The composition and leaching rate of the titanium-rich material are shown in Table 8.

[0097] Table 8. Composition of titanium-rich materials and their leaching rates (wt%)

[0098] After acid leaching, the ωΣ(CaO+MgO) content in the titanium slag was less than 1.5%, the TiO2 recovery rate was 99.24%, the V2O5 leaching rate was 93.21%, the Cr2O3 leaching rate was 68.50%, and the pulverization rate was 0.15%.

[0099] The filtrate from the solid-liquid separation was a hydrochloric acid leaching solution, the composition of which is shown in Table 9.

[0100] Table 9 Composition of hydrochloric acid leaching solution

[0101] Example 5 The titanium slag (titanium-rich material) after acid leaching in Example 4 was placed in an alkaline leaching solution and heated at normal pressure to remove silicon. After alkaline leaching, the leaching slurry was subjected to solid-liquid separation to obtain an alkaline leaching solution and a filter cake. The filter cake was dried to obtain a boiling chlorinated titanium-rich material.

[0102] The specific alkaline leaching process is as follows: continue alkaline leaching of the titanium slag (titanium-rich material) after acid leaching in Example 4 to remove SiO2 from the titanium slag (titanium-rich material) after acid leaching in Example 4. The alkaline leaching conditions are: sodium hydroxide concentration 10wt%, leaching liquid-to-solid ratio 5:1ml / g, leaching temperature 95℃, and leaching time 3h. After the reaction, the leaching slurry is filtered for solid-liquid separation. The filter cake is washed and dried to obtain boiling chlorinated titanium-rich material. The composition and leaching rate of the boiling chlorinated titanium-rich material after alkaline leaching are shown in Table 10.

[0103] Table 10 Composition and leaching rate (wt%) of boiling titanium-rich chlorinated feedstock

[0104] After alkali leaching, the MgO content of the fluidized bed chlorination titanium-rich material is 1.35%, the CaO content is 0.09%, and the SiO2 content is 1.00%. After leaching, ωΣ(CaO+MgO)=1.44%. The content of particles with a size between 60 and 160 mesh in the fluidized bed chlorination titanium-rich material is ≥95%, which meets the requirements of the fluidized bed chlorination process for raw materials.

[0105] Example 6 The composition of the hydrochloric acid leaching solution obtained in Example 4 is shown in Table 9. The treatment method for the hydrochloric acid leaching solution adopts the hydrochloric acid incineration regeneration process widely used in the iron and steel smelting industry. During the hydrochloric acid regeneration process, the Fe in the leaching solution... 2+ / Fe 3+ V2O4 2+ / V2O3 2+ Mg 2+ Al 3+ Mn 2+ Cr 3+ At high temperatures, it hydrolyzes and oxidizes to Fe2O3, V2O5, MgO, Al2O3, MnO, and Cr2O3, respectively. CaCl2, due to its higher hydrolysis temperature, is not hydrolyzed and remains as CaCl2 in the oxide solid phase. - The HCl gas is converted into HCl gas, which is then washed and adsorbed with water to form a 18-20 wt% regenerated hydrochloric acid solution. The composition of the hydrochloric acid regenerated oxide solid phase is shown in Table 11.

[0106] Table 11 Solid phase composition of hydrochloric acid regenerated oxides (wt%)

[0107] The CaCl2 in the oxide solid can be washed away with water. Using twice the weight of water in a three-stage countercurrent washing process, the CaCl2 removal rate can reach over 98%. The composition of the hydrochloric acid-regenerated oxide solid after water washing is shown in Table 12. The vanadium and chromium-rich iron powder in the oxide solid can be used as a high-quality raw material for extracting vanadium and chromium resources.

[0108] Table 12 Composition of the solid phase of hydrochloric acid regenerated oxides after water washing (wt%)

[0109] Example 7 The water-quenched modified titanium slag prepared in Example 3 was crushed, ground, and screened to obtain fluidized bed titanium slag that met the particle size requirements of the fluidized bed chlorination process. The obtained fluidized bed titanium slag was water-quenched modified titanium slag with a particle size range of 60-160 mesh. The 60-160 mesh water-quenched modified titanium slag was further purified using a chloride-oxidant hydrochloric acid leaching system. The reaction conditions were: hydrochloric acid concentration 20wt%, MgCl2 content 0.3mol / L, O2 partial pressure 0.1MPa, leaching liquid-solid ratio 3:1ml / g, leaching temperature 145℃, and leaching time 2h. After the reaction, the leaching slurry was filtered for solid-liquid separation. The filter cake was washed and dried to obtain titanium-rich material. The composition and leaching rate of the titanium-rich material are shown in Table 13.

[0110] Table 13. Composition and leaching rate of titanium-rich materials (wt%)

[0111] After acid leaching, the ωΣ(CaO+MgO) content in the titanium-rich material was less than 1.5%, the TiO2 recovery rate was 99.07%, the V2O5 leaching rate was 93.99%, the Cr2O3 leaching rate was 61.23%, and the pulverization rate was 0.35%. Since the SiO2 content was too high, the titanium-rich material was further subjected to alkaline leaching. The alkaline leaching conditions were: sodium hydroxide concentration 10wt%, leachate liquid-to-solid ratio 5:1 ml / g, leaching temperature 95℃, and leaching time 3h. After the reaction, the leachate slurry was filtered for solid-liquid separation. The filter cake was washed and dried to obtain the fluidized bed chlorinated titanium-rich material. The composition of the fluidized bed chlorinated titanium-rich material is shown in Table 14.

[0112] Table 14 Composition of Boiling Chlorinated Titanium-Rich Material (wt%)

[0113] After alkali leaching, the MgO content of the fluidized bed chlorination titanium-rich material is 1.35%, the CaO content is 0.11%, and the SiO2 content is 0.98%. After leaching, ωΣ(CaO+MgO)=1.46%. The content of particles with a size between 60 and 160 mesh in the fluidized bed chlorination titanium-rich material is ≥95%, which meets the requirements of the fluidized bed chlorination process for raw materials.

[0114] Comparative Example 1 The water-quenched modified titanium slag prepared in Example 3 was crushed, ground, and screened to obtain fluidized bed titanium slag that met the particle size requirements of the fluidized bed chlorination process. The obtained fluidized bed titanium slag had a particle size range of 60-160 mesh. The acid leaching system used 20%wt hydrochloric acid, 50g / L MgCl2, and a leaching temperature of 145℃ to leach the 60-160 mesh water-quenched modified titanium slag (containing titanium materials) without the addition of oxidant. The leachate slurry after the reaction was filtered for solid-liquid separation. The filter cake was washed and dried to obtain titanium-rich material. The composition of the titanium-containing material, the composition of the titanium-rich material, and their leaching rates are shown in Table 15.

[0115] Table 15. Composition of titanium-containing materials, composition of titanium-rich materials and their leaching rates (wt%)

[0116] Without the addition of an oxidant, the TiO2 leaching rate increased to 14.67%, resulting in significant titanium loss.

[0117] Comparative Example 2 The pelletizing, melting, water quenching modification, and acid leaching processes of the raw material vanadium-titanium magnetite concentrate are the same as in Examples 1, 2, 3, and 4, except that bentonite is used instead of Ca(OH)2 as the binder and calcifying agent in the preparation of vanadium-titanium magnetite concentrate pellets. The chemical elemental composition and basic physical properties of the bentonite used are shown in Tables 16 and 17.

[0118] Table 16 Chemical elemental composition of bentonite

[0119] Table 17 Basic Physical Properties of Bentonite

[0120] Vanadium-titanium magnetite concentrate and bentonite (Table 16-17) were added at a ratio of 1.9 parts per 100 parts of vanadium-titanium magnetite concentrate and then milled to prepare green pellets. The green pellets were then oxidized and roasted at 1200℃ for 1 hour to prepare roasted pellets. The water-quenched modified titanium slag after melting was further purified using a chloride-oxidant hydrochloric acid leaching system. The leaching conditions were: hydrochloric acid concentration 20wt%, FeCl3 was selected as both oxidant and chloride, with a total FeCl3 content of 0.3mol / L, a leaching liquid-to-solid ratio of 3:1, a leaching temperature of 145℃, and a leaching time of 2 hours. The composition of the titanium slag after leaching and its leaching rate are shown in Table 18.

[0121] Table 18 Composition of titanium slag after leaching and its leaching rate (wt%)

[0122] When bentonite is used to form pellets, the leaching effect of elements such as V, Ca, and Mg in water-quenched modified titanium slag is poor, and the impurity removal effect is significantly lower than when Ca(OH)2 is used as a binder and calcifying agent.

[0123] Comparative Example 3 The alkaline pelletizing of raw vanadium-titanium magnetite concentrate and the melting-acid leaching process are the same as in Examples 1, 2, 3, and 4, except that the titanium slag after melting is cooled using a conventional cooling method. The composition of the conventionally cooled titanium slag, the composition of the titanium slag after leaching with a chloride-oxidant hydrochloric acid leaching system, and its leaching rate and recovery rate are shown in Table 19.

[0124] Table 19 Composition of conventionally cooled titanium slag, composition of titanium slag after leaching, leaching rate, and recovery rate (wt%)

[0125] Titanium slag obtained using conventional cooling methods, after leaching with a chloride-oxidant hydrochloric acid leaching system, exhibits high levels of impurities such as magnesium, chromium, and vanadium. The leaching result shows ωΣ(CaO+MgO) = 8.45%, which fails to meet the requirements for fluidized bed chlorination. In contrast, conventional titanium slag contains well-developed and more stable black titanium crystals, making Mg elements more difficult to leach.

Claims

1. A method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate, characterized in that, Includes the following steps: Step 1: Mix vanadium-titanium magnetite concentrate with a calcifying agent to prepare alkaline green pellets of vanadium-titanium magnetite concentrate. Then, calcify and oxidize the alkaline green pellets to obtain calcified oxide pellets. Step 2: Mix the calcified oxide pellets with a reducing agent and reduce them at high temperature to reduce Fe2O3 in the calcified oxide pellets to metallic iron, thereby obtaining metallized pellets; Step 3: After melting and separating the metallized pellets with a supplementary calcifying agent, molten iron and molten titanium slag are obtained. The molten titanium slag is mixed with water quenching liquid and water quenched, and then rapidly cooled and granulated to obtain water-quenched modified titanium slag. Step 4: Control the particle size of the water-quenched modified titanium slag to obtain fluidized bed titanium slag that meets the particle size requirements of the fluidized bed chlorination process. Step 5: Acid leaching and solid-liquid separation are performed on the boiling titanium slag to obtain titanium-rich material; Step 6: The titanium-rich material is subjected to alkaline leaching and solid-liquid separation to obtain boiling chlorinated titanium-rich material.

2. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 1, characterized in that, Includes at least one of the following technical features: (1) The diameter of the alkaline green pellets mentioned in step 1 is 9~16mm; (2) The composition of the vanadium-titanium magnetite concentrate mentioned in step 1, by mass percentage, includes TFe 50~60%, TiO2 8~15%, V2O5 0.5~2.0%, SiO2 0.5~5.0%, and CaO 0.1~5%; (3) The calcifying agent mentioned in step 1 is at least one of calcium-containing compounds or calcium-containing minerals; the calcium-containing compound is at least one of CaO, CaSO4, and Ca(OH)2; (4) In step 1, when the alkaline green pellets of vanadium-titanium magnetite concentrate are pelletized, the amount of calcifying agent added is 1.2 to 2.5 parts relative to 100 parts of vanadium-titanium magnetite concentrate; (5) The calcination and oxidation calcination temperature in step 1 is 1150~1250℃, and the calcination time is 20min~10h; (6) The compressive strength of the calcified oxide pellets in step 1 is ≥1500N / piece.

3. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 2, characterized in that, The total amount of calcifying agent added in step 1 and the supplementary calcifying agent added in step 3 is calculated as follows: Relative to 100 parts of vanadium-titanium magnetite concentrate, the total amount of calcifying agent added in step 1 and the supplementary calcifying agent added in step 3 is calculated using the following formula: Wt Ca(OH)2 =K(123Wt SiO2 +41Wt V2O5 -132Wt CaO ), Among them Wt Ca(OH)2 The percentage of the total amount of calcifying agent added, with an excess coefficient K of 1~1.3, Wt SiO2 Wt V2O5 and Wt CaO The percentage contents of SiO2, V2O5 and CaO in titanoma magnetite concentrate are respectively. And the total amount of calcifying agent added (Wt) Ca(OH)2 Not less than 1.2 portions.

4. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 1, characterized in that, Includes at least one of the following technical features: (1) The mass ratio of the calcified oxide pellets to the reducing agent in step 2 is 1:0.1 to 1:2; (2) The reducing agent mentioned in step 2 is at least one of carbon-based substances, hydrogen, and CO; (3) The reduction temperature in step 2 is 900~1300℃ and the reduction time is 30min~20h; (4) The metallization rate of the metallized pellets after reduction in step 2 is ≥90%.

5. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 1, characterized in that, Includes at least one of the following technical features: (1) The melting temperature in step 3 is 1400~1650℃; (2) The water quenching solution mentioned in step 3 is at least one of water, acidic wastewater, ferrous chloride solution and alkaline solution; the alkaline solution is at least one of sodium hydroxide solution, calcium hydroxide solution and potassium hydroxide solution; (3) The water quenching pressure in step 3 is 1~40 kg·f / cm 2 ; (4) The particle size D of the water-quenched modified titanium slag mentioned in step 3 50 =0.1~4mm.

6. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 1, characterized in that, Includes at least one of the following technical features: (1) Step 4 Particle size control: The water-quenched modified titanium slag is crushed, ground, screened and classified to obtain hydrated titanium slag that meets the particle size requirements of the hydrated chlorination process. (2) Step 4 yields a water-quenched modified titanium slag with a particle size range of 40~160 mesh, which meets the particle size requirements of the fluidized bed chlorination process.

7. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 1, characterized in that, Includes at least one of the following technical features: (1) In step 5, the acid leaching is carried out using hydrochloric acid leaching solution, and the boiling titanium slag is acid-leached with hydrochloric acid leaching solution; (2) In step 5, acid leaching is carried out by high temperature and pressure leaching to obtain leaching slurry. The leaching temperature is 110~180℃, the pressure corresponds to the vapor pressure of hydrochloric acid leaching solution at the leaching temperature, the leaching liquid-solid ratio is 1:1~10:1ml / g, and the leaching time is 1~6h. (3) In step 5, the titanium yield during acid leaching is ≥99%, the vanadium leaching rate is ≥90%, the chromium leaching rate is ≥50%, the calcium leaching rate is ≥95%, the magnesium leaching rate is ≥93%, and the pulverization rate of the fluidized bed titanium slag after acid leaching is ≤0.5% of the -96μm size. (4) In step 5, the solid-liquid separation also yields a hydrochloric acid leaching solution.

8. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 7, characterized in that, Includes at least one of the following technical features: (1) The hydrochloric acid leaching solution includes hydrochloric acid, chloride salt and oxidant; (2) The concentration of the hydrochloric acid solution is 15~25wt%; (3) The chloride salt is at least one of FeCl3, FeCl2, AlCl3, MgCl2, and CaCl2, and the chloride salt content is 0.1~1.5 mol / L; (4) The oxidant is at least one of FeCl3, O2, NaClO, H2O2, Cl2, and KMnO4, and the content of the oxidant is 0.1~3.0 mol / L, or the partial pressure of the oxidant is 0.1~1 MPa.

9. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 7, characterized in that, The hydrochloric acid leaching solution is spray-fired at a high temperature to generate oxide solids and hydrochloric acid gas. The spray-fire temperature is 550~750℃. The hydrochloric acid gas is then absorbed by water spraying in a multi-stage countercurrent to generate a regenerated hydrochloric acid solution with a concentration of 18~22wt%. The regenerated hydrochloric acid solution is returned to the acid leaching process.

10. The method for preparing hydrated titanium-rich material from vanadium-titanium magnetite concentrate according to claim 1, characterized in that, Includes at least one of the following technical features: (1) In step 6, the titanium-rich material is placed in an alkaline leaching solution and heated under normal pressure to remove silicon. The leaching temperature is 40~100℃, the leaching liquid-solid ratio is 0.5:1~20:1ml / g, and the leaching time is 1~6h. (2) The alkaline leaching solution in step 6 is at least one of sodium hydroxide, potassium hydroxide, or lithium hydroxide, and the concentration of the alkaline leaching solution is 5-80 wt%. (3) The composition of the boiling chlorinated titanium-rich material obtained in step 6, by mass percentage, includes TFe≤2.0%, TiO2≥85.00%, SiO2≤1.00%, MgO≤1.35%, CaO≤0.15%, and ωΣ(CaO+MgO)≤1.50%.

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