Efficient comprehensive utilization method of vanadium-titanium magnetite

Abstract

The application provides a high-efficiency comprehensive utilization method of vanadium-titanium magnetite, and relates to the technical field of non-ferrous metallurgy. The method takes a concentrate selected from vanadium-titanium magnetite as a raw material, and obtains a Fe(V)-Ti(C, N, O) / Ti(C, O)-MOx mixture by agglomeration and reduction after adding a carbonaceous reducing agent according to a specific principle; the mixture is subjected to magnetic separation to obtain non-magnetic substances and magnetic substances; the non-magnetic substances are subjected to hydrochloric acid leaching to obtain a titanium-rich material, and the titanium-rich material is subjected to soluble anode electrolysis to prepare metallic titanium or low-temperature chlorination to obtain TiCl4; the magnetic substances are subjected to smelting and purification to be used as an anode, and the Fe(V)-Ti(C, N, O) / Ti(C, O)-MOx mixture after hydrochloric acid leaching and purification treatment is subjected to electrolytic refining in an acid solution to prepare high-purity iron; and vanadium is enriched and recovered in the purified vanadium-containing slag and the electrolytic refining anode mud. 2+ The method takes titanium extraction as a core, does not need to make slag, improves the utilization rates of titanium, iron and vanadium, avoids various problems caused by large slag quantity in the traditional process, has simple process, low energy consumption, high controllability and environmental protection and no pollution, and is beneficial to industrial large-scale production and popularization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-ferrous metallurgy, in particular to a high-efficiency comprehensive utilization method of vanadium-titanium magnetite. BACKGROUND

[0002] Vanadium-titanium magnetite is a complex ore in which iron, titanium, vanadium and other valuable elements coexist. The total iron content in the raw ore is generally 20-35%, the titanium dioxide content is 5-15%, the vanadium pentoxide content is 0.1-0.8%, and the contents of gallium and scandium are relatively low. It is a mineral resource with extremely high comprehensive utilization value. The comprehensive utilization of various valuable elements in vanadium-titanium magnetite has been the goal of metallurgical technology workers for many years.

[0003] Currently, the comprehensive utilization of vanadium-titanium magnetite is basically centered on iron extraction, and the process routes mainly include two types:

[0004] (1) "blast furnace-converter" process route

[0005] This process has obvious advantages in production capacity due to the use of blast furnace ironmaking. However, the problems of this process are also very prominent, mainly reflected in the low utilization rate of valuable elements Fe, Ti, and V: (1) The iron grade of vanadium-titanium magnetite concentrate is low, and a large amount of dolomite needs to be added for slagging during blast furnace smelting, resulting in a large amount of slag with high iron content (2-3%) in the slag, which makes the iron utilization rate only about 66% (semi-steel). Even if the iron produced by the electric furnace smelting of titanium concentrate is included, the iron utilization rate is only about 80%.(2) More than half of the Ti in the raw ore enters the vanadium-titanium magnetite concentrate, and enters the blast furnace slag after blast furnace smelting. This part of Ti cannot be utilized so far, the main reason is that the Ti content in the slag is low, and the titanium-containing minerals are dispersedly distributed, which is difficult to separate and enrich by beneficiation. In addition, part of Ti cannot be utilized during the electric furnace smelting of titanium concentrate, resulting in a titanium utilization rate of only 12% (sponge titanium) -18% (titanium white) in the raw ore.(3) About 82% of V in the raw ore enters the vanadium-titanium magnetite concentrate, and only about 55% enters the vanadium-containing molten iron after blast furnace smelting, and the remaining V enters the blast furnace slag which cannot be utilized. In addition, part of vanadium enters the titanium concentrate, which is difficult to utilize due to its low content. The above results in a vanadium utilization rate of only 39% (vanadium pentoxide).

[0006] In view of the problem that the blast furnace slag of the blast furnace-converter process cannot be effectively utilized, researchers have made a lot of research in the past few decades to try to find a solution, such as the high-temperature carbonization-low-temperature chlorination process developed by Pansteel Group (such as patent CN105819500B), but all of them have not been truly applied due to economic reasons. Therefore, to improve the utilization rate of valuable elements in vanadium-titanium magnetite, it is necessary to find a metallurgical process other than blast furnace.

[0007] (2) "direct reduction-electric furnace melting and separation" process route

[0008] In order to solve the problem of inefficient utilization of titanium in the blast furnace-converter process, researchers have proposed a process based on direct reduction technologies such as rotary hearth furnace and shaft furnace to treat vanadium-titanium magnetite, namely the "direct reduction-electric furnace smelting separation" process. In the past few decades, researchers have conducted a series of studies and explorations in this regard, and have basically solved the related process problems, such as patents CN120119058A and CN120060584A. Practice shows that the iron utilization rate of this process reaches 90% (semi-steel), the vanadium utilization rate is 50% (vanadium pentoxide), and the titanium utilization rate is 70% (sponge titanium) -75% (titanium white), which is an improvement of varying degrees compared with the blast furnace-converter process.

[0009] However, the direct reduction-electric furnace smelting separation process also has problems that are difficult to overcome. The main problem is that during the electric furnace smelting separation, a slagging agent needs to be added to promote the separation of slag and molten iron, resulting in a low TiO2 content (40-60%) in the titanium-containing slag. The presence of a large amount of oxide impurities MOx (M is calcium, magnesium, aluminum, and silicon) in the titanium-containing slag makes it necessary to use the sulfuric acid method to produce titanium white. The sulfuric acid method of producing titanium white already has problems such as complex process, long production cycle, and difficult treatment of waste acid. Moreover, the low TiO2 grade in the titanium-containing slag requires a larger amount of sulfuric acid, which not only increases the load of the process flow but also makes the problems of the sulfuric acid method more prominent.

[0010] In addition, the direct reduction-electric furnace smelting separation process has not fundamentally solved the problem of low V utilization rate. Although compared with the blast furnace-converter process, the vanadium utilization rate has increased from 45% to 57% (vanadium slag), there is still 17% of vanadium in the titanium-containing slag that is not effectively utilized (in the blast furnace-converter process, about 27% of vanadium enters the high-titanium blast furnace slag, and about 5% of vanadium enters the high-titanium slag, totaling about 32% of vanadium that cannot be utilized).

[0011] In addition to the two industrialized process routes mentioned above, there are other methods or process routes, some of which are more representative: 1) Direct preparation of ferrotitanium alloy from ilmenite, such as patent CN101509139A. However, these methods produce ferrotitanium alloy containing a large amount of aluminum and silicon, which can only be used as a steelmaking additive, reducing the utilization rate and value of titanium, and the vanadium in ilmenite is not utilized. 2) Pure wet separation of iron, vanadium, and titanium, such as patent CN119843047A. However, wet separation not only has a slow reaction rate, low processing scale, and low efficiency, but also the titanium slag obtained contains only 68-75% TiO2, which cannot be directly treated by the chlorination method. 3) Selective reduction-low temperature chlorination to extract titanium and vanadium, such as Liu Maosheng. Extraction of titanium and vanadium from vanadium-titanium magnetite by low-temperature chlorination method [J]. Rare Metals and Hard Metals, 1992 (108): 37-41. However, this method.

[0012] The cooperative recycling effect of titanium, iron and vanadium is not very good, not only the selection reduction effect is poor, but also a part of vanadium is not effectively utilized, and the utilization rates of iron and vanadium are both unsatisfactory.

[0013] Therefore, it is necessary to improve, supplement and perfect the existing process from the aspects of process flow and parameter control, and design a disruptive process route to realize the efficient comprehensive utilization of vanadium-titanium magnetite. SUMMARY

[0014] The purpose of the present application is to provide an efficient comprehensive utilization method of vanadium-titanium magnetite. Compared with the prior art, the method provided by the present application utilizes the titanium concentrate and vanadium-titanium magnetite concentrate obtained by beneficiation of vanadium-titanium magnetite raw ore, improves the separation effect of titanium and iron without adding slag forming agent, avoids the problem of slag in the existing process, fully considers the trend of valuable elements in each link, utilizes the respective smelting characteristics to utilize the waste acid, waste slag and waste heat generated, saves raw materials and energy consumption, improves the utilization rate of valuable elements, especially titanium, and perfects the efficient comprehensive utilization process of vanadium-titanium magnetite taking titanium extraction as the core.

[0015] An efficient comprehensive utilization method of vanadium-titanium magnetite, the efficient comprehensive utilization method of vanadium-titanium magnetite comprises the following steps:

[0016] S1, selection of raw materials and addition of carbonaceous reducing agent: taking the titanium concentrate and vanadium-titanium magnetite concentrate obtained by beneficiation of vanadium-titanium magnetite raw ore or the mixed concentrate with any proportion of the two as the raw material; according to the composition and content of the concentrate raw material, the carbonaceous reducing agent is calculated and added according to a specific principle, and the concentrate and the carbonaceous reducing agent are fully mixed;

[0017] S2, pellet preparation and carbothermic reduction: a small amount of additive is added to the fully mixed concentrate and carbonaceous reducing agent of S1 and mixed uniformly to prepare pellets; then selective carbothermic reduction is carried out in a vacuum, argon or nitrogen-containing atmosphere to obtain a mixed product of Fe(V) alloy-Ti(C, N, O) / Ti(C, O)-MOx;

[0018] S3, crushing, fine grinding and magnetic separation: the mixed product of S2 is crushed and finely ground to obtain a finely ground mixture; then the finely ground mixture is separated by countercurrent wet magnetic separation to obtain non-magnetic substances and magnetic substances; the non-magnetic substances are mainly a mixture of Ti(C, N, O) / Ti(C, O)-MOx, and the magnetic substances are mainly Fe(V) alloy;

[0019] S4, treatment of non-magnetic substances: the non-magnetic substances of S3 are leached with hydrochloric acid, and after leaching, filtration separation is carried out to obtain a titanium-rich material and a Fe 2+ acid solution; the vanadium compounds that are not completely reacted in the selective reduction process dissolve into the Fe 2+ acid solution in the hydrochloric acid leaching process;

[0020] There are two ways to use the titanium-rich material: one is to directly prepare metallic titanium by using the method of soluble anode electrolysis; the other is to prepare sponge titanium or titanium white powder after low-temperature chlorination into TiCl4;

[0021] S5, processing of magnetic substance: melting and casting the magnetic substance of S3 into rough iron anode plate, and using the purified Fe 2+ acid liquid as electrolyte, electrolytic refining to prepare high-purity iron with purity ≥99.99%; Fe 2+ V in the acid liquid is enriched into vanadium-containing slag during purification treatment; V in the magnetic substance is enriched into vanadium-containing anode mud during electrolytic refining;

[0022] S6, recycling of V: mixing the vanadium-containing slag and vanadium-containing anode mud of S5, and recycling the valuable element V therein by using water method to extract vanadium.

[0023] Optionally, the principle of calculating and adding carbonaceous reducing agent in S1 is as follows: all iron oxides are reduced into Fe, all TiO2 is reduced into Ti2CO, part of SiO2 is reduced and forms Fe-2%Si alloy, all V2O5 is reduced into V, all Cr2O3 is reduced into Cr, all ZnO is reduced into Zn, and all MnO is reduced into Mn; if the carbonaceous reducing agent used is not high-purity graphite, the ash content and composition of the carbonaceous reducing agent need to be considered during calculation.

[0024] Optionally, the additive in S2 is borax, and the addition amount is 0.1-1%; the size of the pellet is 3-30mm;

[0025] under vacuum reduction, the reduction temperature is 800-1400℃, the vacuum degree is 10 -4 -10 4 Pa; or under argon reduction, the content of argon in the atmosphere is ≥80%, the rest is CO and H2, and there is no O2 and CO2, the reduction temperature is 1100-1700℃; the reduction time is 2-10h; under vacuum or argon atmosphere reduction, the obtained mixed product is Fe(V) alloy-Ti(C, O)-MOx;

[0026] or under nitrogen reduction, the content of nitrogen in the atmosphere is ≥65%, the rest is CO and H2, and there is no O2 and CO2, the reduction temperature is 900-1500℃; the reduction time is 2-10h; the obtained mixed product is Fe(V) alloy-Ti(C, N, O)-MOx.

[0027] Optionally, in S3, the crushing and fine grinding is to dissociate the Fe(V) alloy and Ti(C, N, O) / Ti(C, O)-MOx in the mixed product from the micro scale, and the fine grinding particle size is <50μm; the magnetic field strength for magnetic separation is 800-1800GS.

[0028] Optionally, in S4, the acid concentration of the hydrochloric acid leaching is 3-30%, the liquid-solid ratio is 5-50 ml / g, the leaching time is 0.5-2 h, and the leaching temperature is 20-90℃; to improve the leaching effect, appropriate stirring or ultrasonic assistance is used; the obtained titanium-rich material mainly contains Ti(C, N, O) / Ti(C, O)>80%, Fe<1%, and the rest is MOx; the filtrate contains FeCl2, a small amount of V, and impurities such as Ca, Mg, Al, Cr, Zn, Mn, Cu, Pb, etc.

[0029] Optionally, in S4, when the soluble anode electrolysis method is used to prepare metallic titanium, the titanium-rich material needs to be processed into a high-density and high-strength anode block with a density≥4.5 g / cm 3 . The processing method is preferably hot-pressing sintering, hot isostatic pressing sintering, or high-temperature melting casting; the electrolysis is carried out in a molten salt containing 1-6% of single Ti 2+ or Ti 3+ ions, the cathode current density is 0.1-0.5 A / cm 2 , the anode current density is 0.01-0.2 A / cm 2 (single Ti 2+ ) or 0.2-0.5 A / cm 2 (single Ti 3+ ); every 30-40 h of electrolysis, the molten salt needs to be purified, and the method used is pre-electrolysis or the introduction of HCl / Cl2(chloride molten salt) or HF / F2(fluoride molten salt);

[0030] When the low-temperature chlorination method is used, argon / nitrogen gas preheated to 250-300℃ is used as the carrier gas, the titanium-rich material powder is sprayed from the side into the reaction zone and moves downward under the action of gravity; chlorine gas or a mixture of chlorine gas and argon / nitrogen gas preheated to 250-300℃ enters the reaction zone from the bottom and moves upward, reacts with the downward-moving titanium-rich material, and releases reaction heat; the released reaction heat raises the temperature of the reaction zone, and the temperature of the reaction zone needs to be controlled at 300-500℃; the pressure at the lower part of the reaction zone is 1-3 atm (of which the chlorine gas partial pressure accounts for≥20%), the pressure at the upper part is 0.8-1 atm, and the pressure difference between the upper and lower parts is maintained≥0.2 atm; the mixed gas after the reaction is discharged together with the smoke dust from the upper part of the reaction zone, and after treatment such as dust collection, condensation, and refining, TiCl4 is obtained.

[0031] Optionally, in the low-temperature chlorination process, the preheating of the gas is carried out using the reaction heat released by the chlorination reaction, and the specific method is to cool the reaction zone with the gas at a temperature<250℃, absorb the excess reaction heat through heat conduction, and preheat the gas while controlling the temperature of the reaction zone at 300-500℃.

[0032] Optionally, the smelting and casting of the magnetic substance in S5 is carried out in a vacuum device with stirring function, such as a mechanical stirring vacuum smelting furnace, a blowing stirring vacuum smelting furnace, a vacuum induction smelting furnace, a vacuum suspension smelting furnace, etc., and the vacuum degree is 10 -3 -10 2 Pa, the smelting temperature is 1550-1750℃, and the stirring time is 30-90 minutes before casting, so as to preliminarily refine the melt by vacuum stirring and remove gas and volatile impurity elements such as C, P, S, N, Pb, Zn, Mn, Ca, Mg, etc. in the melt.

[0033] Optionally, the Fe 2+ concentration in the acid liquor is removed by recycling V and removing Ca, Mg, Al, Cr, Zn, Mn, Cu, Pb, etc. The purification process needs to be selected according to the V concentration in the Fe 2+ acid liquor: when the V concentration is >0.2 g / L, the process of "NaF precipitation-ion exchange resin adsorption-extraction" is selected, and when the V concentration is <0.2 g / L, the process of "NaF precipitation-strong acid cation resin adsorption-electrolysis" is selected; inert gas protection is required during purification to avoid Fe 2+ oxidation to Fe 3+ .

[0034] Optionally, high-purity iron is prepared by electrolytic refining in S5, and the Fe 2+ concentration of the electrolyte is adjusted to 0.2-1.2 mol / L, and the pH value is adjusted to 1-3 by adding FeCl2 and sodium carbonate / sodium bicarbonate; the electrolysis temperature is 40-60℃, the current density is 50-300 A / m 2 , and the electrode is replaced every 20-60 h; the electrolyte is circulated during electrolysis, and the circulation flow rate is 2-3 L / min; before the recycled electrolyte reenters the electrolysis tank, it needs to be purified according to the Fe 2+ acid liquor purification method.

[0035] Optionally, during the preparation of high-purity iron by electrolytic refining, 0.5-1.5 g / L ascorbic acid is added to the purified electrolyte to inhibit the occurrence of Fe 3+ ; 0.05-0.5% iso-octanol and 2-6 g / L sodium fluoride are added to promote the aggregation and precipitation of V and Al, Si, etc. impurities in the anode mud, so as to avoid the excessive anode mud affecting the electrolysis process, and the anode mud is cleaned every 6-10 h.

[0036] Optionally, the utilization rates of titanium, iron and vanadium in the high-efficiency comprehensive utilization method of vanadium-titanium magnetite are 75% (sponge titanium)-80% (titanium white), ≥71% (high-purity iron), and ≥61% (vanadium pentoxide), respectively.

[0037] Optionally, the efficient comprehensive utilization method of vanadium-titanium magnetite is also suitable for the comprehensive utilization of other titanium-containing minerals such as rutile, high-titanium slag, sea sand ore, high-titanium blast furnace slag of blast furnace-converter process, and titanium-containing slag of direct reduction-electric furnace melting process.

[0038] Technical principles of the present application:

[0039] The inventors believe that the fundamental reason for the poor comprehensive utilization effect of vanadium-titanium magnetite is that current methods or process routes are based on "iron" as the core and focus on extracting iron first and then utilizing other valuable metals. To fundamentally solve this problem, we must break the convention and establish a new idea centered on titanium extraction. For this reason, the team of the inventors has been working in this direction for more than ten years and has developed a method of "selective reduction-molten salt electrolysis / low-temperature chlorination" for extracting titanium, iron, and vanadium, with titanium extraction as the core. For example, patents CN115216810B, CN105907968B, CN109055781B, CN110093504B, CN113046577B, CN100415940C, and CN101187042A. This method first combines vanadium-titanium-iron composite concentrate into a mixture of Fe(V) alloy-Ti(C, N, O) / Ti(C, O)-MOx through selective carbon thermal reduction, then separates the titanium-rich material Ti(C, N, O) / Ti(C, O)-MOx through melting or magnetic separation, and finally obtains metallic titanium through molten salt electrolysis with the titanium-rich material as the soluble anode, or obtains TiCl4 by low-temperature chlorination of the titanium-rich material. This method is particularly suitable for vanadium-titanium magnetite due to its short process, low energy consumption, and high comprehensive utilization rate of Ti, Fe, and V, and no requirement for calcium and magnesium content in the raw material.

[0040] The inventors noticed that selective reduction-low-temperature chlorination has been around since the 1960s, and domestic semi-industrial tests were conducted in the 1980s-1990s (Liu Maosheng, et al. Low-temperature boiling chlorination method for producing titanium tetrachloride from carbon-nitrogen-titanium oxide semi-industrial test[J]. Sichuan Metallurgy, 1984(2):60-65). However, at that time, the selective reduction process was not well understood, and TiO2 was converted into a titanium-containing mixture of Ti3O5, Ti2O3, TiN, TiC, and Ti(C, N, O), with a conversion rate of only 85-95%. Even so, the titanium-containing mixture can still complete boiling chlorination normally at 500-700°C, with a chlorination rate of titanium reaching 85-98%, fully verifying the feasibility and industrialization potential of low-temperature chlorination. Vanadium in the raw material is simultaneously chlorinated during low-temperature chlorination and is recovered after purification and refining of TiCl4.

[0041] Previous research by the inventors' team has solved the selective reduction problem, enabling the stable conversion of TiO2 into single Ti(C, N, O) or Ti(C, O) with a conversion rate >98%. Single Ti(C, N, O) / Ti(C, O) not only has a lower chlorination temperature (150-500℃), but also maintains a stable chlorination rate of >98% under the same conditions. Nevertheless, in practical applications, the "selective reduction-molten salt electrolysis / low-temperature chlorination" process still faces the following problems that urgently need to be addressed:

[0042] 1. Efficient separation of titanium and iron in reduction products. In selective reduction products, Ti(C,N,O) / Ti(C,O) and metallic iron form a microstructure of intergrowth and embedding at the <10 micrometer scale, making the separation of titanium and iron difficult. Previous solutions involved adding slag-forming agents such as soda ash, lime, dolomite, and MgO, which increases slag volume, reduces the grade of titanium-rich feedstock, and complicates subsequent electrolysis / chlorination. Fine grinding followed by magnetic separation can also separate titanium and iron, but the <10 micrometer grinding particle size requirement increases the grinding difficulty and the separation effect is not ideal.

[0043] 2. Removal of MOx and Fe from Titanium-Rich Materials. Even without slag-forming agents in the selective reduction process, the MOx content in the titanium-rich materials separated by melting or magnetic separation is still around 20%, with an additional 4-12% metallic Fe. Although MOx does not participate in electrolysis / low-temperature chlorination, it increases the slag discharge burden and affects process stability; metallic Fe, on the other hand, does participate in electrolysis / low-temperature chlorination, increasing power or chlorine consumption. Currently, there are two removal methods. One is high-temperature filtration, which utilizes the high melting point (>2300℃) of Ti(C,N,O) / Ti(C,O) to filter and remove MOx and Fe at a high temperature of 1600-1800℃. However, due to the extremely fine particle size (<10 micrometers) of Ti(C,N,O) / Ti(C,O), the filtration effect is poor and the energy consumption is high. Another method is to pickle the titanium-rich material to remove MOx and Fe, which can yield Ti(C,N,O) / Ti(C,O) with a purity of >90%. However, the pickling solution contains a large number of Fe ions, so comprehensive recycling and utilization should be considered to improve the comprehensive utilization rate of iron and increase its added value.

[0044] 3. Overheating in low-temperature chlorination reactions. The chlorination of Ti(C,N,O) / Ti(C,O) is an exothermic reaction, with a greater thermal effect than the chlorination of TiO2 with carbon, easily leading to localized overheating and sintering of the furnace charge. Previous solutions included diluting the materials and chlorine gas to slow the reaction rate, rapidly exchanging heat, or adding a heat carrier to increase the heat capacity of the furnace charge. However, these methods all reduce chlorination efficiency and increase chlorine consumption to varying degrees. The best solution is to develop a new chlorination method.

[0045] Patent CN105197989B proposes a flash suspension chlorination method for titanium-containing raw materials, providing insights for the development of new chlorination methods. However, the titanium-containing raw material it targets is TiO2, which requires raising the temperature of the reaction zone to 550-1000℃ before chlorination. Although no carbon is added to the chlorination raw material, carbon needs to be continuously sprayed during the reaction to maintain a reducing atmosphere so that the chlorination process can proceed smoothly, which actually increases carbon consumption.

[0046] 4. The recycling and utilization of vanadium (V) needs improvement. Although thermodynamic calculations indicate that the carbothermic reduction of V is easier than that of Fe, in practice, the selective carbothermic reduction rate of V is only about 55%, far lower than that of Fe (>98%) and Ti (>98%). The reduced V enters metallic Fe to form Fe(V) alloys. Although it can be recovered through a converter vanadium extraction process, about 13% still enters semi-steel production and is used at a low value. The unreduced vanadium enters titanium-rich materials, and although it can be extracted from the purified slag during low-temperature chlorination, the utilization rate is unsatisfactory.

[0047] Therefore, the present invention provides a method for the efficient comprehensive utilization of vanadium-titanium magnetite, which includes the selection of raw materials and the addition of carbonaceous reducing agents, pellet preparation and carbothermic reduction, crushing, fine grinding and magnetic separation, treatment of non-magnetic materials, treatment of magnetic materials, and recovery and utilization of V.

[0048] The chemical formulas used in calculating carbon content are as follows:

[0049] Fe₂O₃ + 3C = 2Fe + 3CO;

[0050] FeO + C = Fe + CO;

[0051] TiO2 + 2C = 0.5Ti2CO + 1.5CO;

[0052] SiO2 + 2C = Si + 2CO;

[0053] V₂O₅ + 5C = 2V + 5CO;

[0054] Cr₂O₃ + 3C = 2Cr + 3CO;

[0055] ZnO + C = Zn + CO;

[0056] MnO + C = Mn + CO;

[0057] In this process, SiO2 is only partially reduced to produce Fe-2%Si alloy. The principle for calculating the amount of carbon is as follows: first, calculate and determine the amount of Fe based on the content of iron oxides in the raw materials; then, calculate the required amount of Si based on the composition of Fe-2%Si alloy; and finally, calculate the required amount of carbon by reverse calculation based on the reaction formula SiO2+2C=Si+2CO.

[0058] Carbonaceous reducing agents specifically include at least one of the following: graphite, activated carbon, charcoal, petroleum coke, pitch, coke powder, and coal powder. Except for graphite, which generally has a carbon content of over 99%, other carbonaceous reducing agents typically contain ash, some of which contains iron oxides, titanium oxides, etc. Therefore, when calculating the amount of carbonaceous reducing agent to be added, the ash content and composition must also be considered to reduce deviations in carbon consumption during the actual reaction.

[0059] In the selective carbothermic reduction process, if reducing gases such as CO and H2 are present, their presence can promote the reduction process to a certain extent. If oxidizing gases such as O2 and CO2 are present, they will consume the carbon in the feed at the reduction temperature, thereby increasing carbon consumption and reducing the reduction rate of oxides. In severe cases, this can lead to insufficient reduction rates of key iron oxides and TiO2.

[0060] In the mixed products of selective carbothermic reduction, Ti(C,O) and Ti(C,N,O) have similar crystal structures and properties, and their subsequent processing is exactly the same. Furthermore, although Fe(V) alloys also react with nitrogen in a nitrogen atmosphere to form Fe(V)-N alloys, this does not affect the properties of the Fe(V) alloys and has no impact on subsequent processes such as magnetic separation and acid leaching.

[0061] During the crushing and grinding process, although adding borax can promote the aggregation and growth of the metallic iron phase to a certain extent, it only grows from less than 10 micrometers to about 50 micrometers. Therefore, it is still necessary to first dissociate Fe(V) and Ti(C,N,O) / Ti(C,O)-MOx from the microscopic level through fine grinding, and then separate them by magnetic separation.

[0062] During hydrochloric acid leaching, most of the non-magnetic substances, except for Ti(C,N,O) / Ti(C,O) and SiO2, can be dissolved, thus obtaining high-grade titanium-rich materials.

[0063] Using titanium-rich Ti(C,N,O) / Ti(C,O) as a soluble anode for electrolytic preparation of metallic titanium is considered a promising low-cost method for industrial-scale production. Key influencing factors include anode density, current density, the coexistence of multivalent titanium ions in the molten salt, and the oxygen content of the molten salt. Controlling these factors is crucial for the success of soluble anode electrolysis.

[0064] By reacting the titanium-rich material in powder form with countercurrent Cl2, the contact area and contact time are increased, thereby improving the chlorination rate of the titanium-rich material while avoiding the concentrated release of reaction heat. Furthermore, using the reaction heat to preheat the carrier gas and chlorine not only absorbs excess heat and stabilizes the reaction temperature at 300-500℃, but also makes the chlorination reaction more favorable.

[0065] Because the vanadium-titanium magnetite raw materials have different vanadium content, after selective carbothermic reduction-magnetic separation-acid leaching, the Fe content...2+ The concentration of V in acid solutions fluctuates significantly, therefore the purification process, especially the enrichment and recovery of V, varies: for acid solutions with a V concentration > 0.2 g / L, the "NaF precipitation-ion exchange resin adsorption-extraction" process can be selected for purification and enrichment and recovery of V; for acid solutions with a V concentration < 0.2 g / L, the "NaF precipitation-strong acid cation exchange resin adsorption-electrolysis" process is recommended for purification and enrichment and recovery of V.

[0066] Thus, the valuable elements titanium, iron, and vanadium in vanadium-titanium magnetite have been efficiently and synergistically extracted and utilized, with Ti utilization rate of 75% (sponge titanium)-80% (titanium dioxide), Fe utilization rate of ≥71% (high-purity iron), and V utilization rate of ≥61% (vanadium pentoxide).

[0067] The above technical solution has at least the following advantages compared with the existing technology:

[0068] The above-described scheme, the present invention, is a highly efficient comprehensive utilization method for vanadium-titanium magnetite with titanium extraction as the core. Using concentrate from vanadium-titanium magnetite ore as raw material, non-magnetic Ti(C,N,O) / Ti(C,O)-MOx and magnetic Fe(V) are obtained through selective carbothermal reduction-magnetic separation. The non-magnetic material is leached with hydrochloric acid to obtain titanium-rich material, which is then electrolyzed with a soluble anode to prepare metallic titanium, or chlorinated at low temperature to TiCl4. The magnetic material, after smelting and purification, is used as the anode, and the purified Fe-containing material is then subjected to hydrochloric acid leaching. 2+ High-purity iron is prepared by electrolytic refining in acid solution; vanadium is enriched and recovered in the purification of vanadium-containing slag and electrolytic refining anode mud.

[0069] The process flow of this invention fully considers the physicochemical properties of waste residue, waste acid, and waste heat generated in each stage, achieving recycling and reducing emissions while improving the comprehensive utilization rate of valuable elements. Compared with the existing blast furnace-converter process with titanium utilization rates of 12% (sponge titanium)-18% (titanium dioxide), iron utilization rate of 80% (semi-steel), and vanadium utilization rate of 39% (vanadium pentoxide), and the direct reduction-electric furnace melting process with titanium utilization rates of 70% (sponge titanium)-75% (titanium dioxide), iron utilization rate of 90% (semi-steel), and vanadium utilization rate of 50% (vanadium pentoxide), the present invention achieves titanium utilization rates of 75% (sponge titanium)-80% (titanium dioxide), iron utilization rate of ≥71% (high-purity iron), and vanadium utilization rate of ≥61% (vanadium pentoxide). The utilization rates of titanium and vanadium are improved to varying degrees. Although the iron utilization rate is somewhat reduced, its product is 99.99% high-purity iron, which is nearly 100 times more expensive than semi-steel. The high added value is enough to compensate for the adverse effects of the reduced utilization rate.

[0070] This invention provides a highly efficient comprehensive utilization method for vanadium-titanium magnetite. During the low-temperature chlorination process of titanium-rich materials, the titanium-rich materials move counter-currently with Cl2, fully utilizing the characteristics of Ti(C,N,O) / Ti(C,O) chlorination—low temperature, short reaction time, and high efficiency. The chlorination process requires no carbon addition and no need to maintain a reducing atmosphere, effectively saving raw materials compared to existing flash suspension chlorination methods. The carrier gas and chlorine absorb excess reaction heat, stabilizing the chlorination temperature while preheating the materials, allowing for a more complete chlorination reaction and increasing the chlorination rate. The titanium-rich materials do not agglomerate; they are dispersed in powder form and react with chlorine, increasing the contact area and making the reaction faster than with boiling chlorination. Furthermore, the reaction heat is further dispersed, avoiding technical problems such as furnace charge sintering caused by localized overheating during the chlorination process, which are present in existing low-temperature boiling chlorination methods.

[0071] In summary, compared with other traditional methods, the method of this invention synergistically improves the utilization rate of titanium, iron and vanadium through the selection of raw materials and the addition of carbonaceous reducing agents, pellet preparation and carbothermic reduction, crushing and fine grinding and magnetic separation, treatment of non-magnetic materials, treatment of magnetic materials, and recycling of V. This method does not require slag production, avoiding various problems caused by large slag volume in traditional processes. The process is simple, energy-efficient, highly controllable, and environmentally friendly, which is conducive to large-scale industrial production and promotion. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0073] Figure 1 This is a process flow diagram of a method for the efficient comprehensive utilization of vanadium-titanium magnetite according to the present invention;

[0074] Figure 2 This is the non-magnetic product XRD pattern of a highly efficient comprehensive utilization method for vanadium-titanium magnetite according to Embodiment 1 of the present invention;

[0075] Figure 3 This is the XRD pattern of the magnetic product of a method for efficient comprehensive utilization of vanadium-titanium magnetite according to Embodiment 1 of the present invention. Detailed Implementation

[0076] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0077] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0078] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0079] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0080] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0081] A method for the efficient and comprehensive utilization of vanadium-titanium magnetite, wherein the method combines... Figure 1 The following steps are required:

[0082] S1. Selection of raw materials and preparation of carbonaceous reducing agent: Titanium concentrate, vanadium-titanium magnetite concentrate or a mixture of both in any proportion obtained by beneficiation of vanadium-titanium magnetite raw ore are used as raw materials; according to the composition and content of the concentrate raw materials, carbonaceous reducing agent is calculated and prepared according to specific principles, and the concentrate and carbonaceous reducing agent are thoroughly mixed.

[0083] S2, Pellet Preparation and Carbothermic Reduction: A small amount of additives are added to the concentrate and carbonaceous reducing agent after thorough mixing in S1 and mixed evenly to form pellets; then selective carbothermic reduction is carried out in vacuum, argon or nitrogen atmosphere to obtain a mixed product of Fe(V) alloy-Ti(C,N,O) / Ti(C,O)-MOx.

[0084] S3, Crushing, Fine Grinding and Magnetic Separation: The mixed product of S2 is crushed and finely ground to obtain a finely ground mixture; then the finely ground mixture is separated by countercurrent wet magnetic separation to obtain non-magnetic and magnetic materials; the non-magnetic material is mainly a mixture of Ti(C,N,O) / Ti(C,O)-MOx, and the magnetic material is mainly Fe(V) alloy.

[0085] S4. Treatment of non-magnetic materials: The non-magnetic materials of S3 are leached with hydrochloric acid, and then filtered and separated to obtain titanium-rich materials and Fe-containing materials. 2+ Acid solution; during the selective reduction process, unreacted vanadium compounds dissolve into the Fe-containing solution during hydrochloric acid leaching. 2+Acid;

[0086] There are two ways to utilize titanium-rich materials: one is to directly prepare metallic titanium using a soluble anodic electrolysis method; the other is to chlorinate it at low temperature to TiCl4, and then prepare it into sponge titanium or titanium dioxide.

[0087] S5. Treatment of magnetic materials: The magnetic materials from S3 are melted and cast into crude iron anode plates, and the purified Fe-containing materials from S4 are used as the anode plates. 2+ The acid solution is used as the electrolyte, and electrolytic refining is used to prepare high-purity iron with a purity ≥99.99%; containing Fe 2+ V in acidic solutions is enriched in vanadium-containing slag during purification; V in magnetic materials is enriched in vanadium-containing anode mud during electrolytic refining.

[0088] S6 and V recycling: The vanadium-containing slag and vanadium-containing anode mud of S5 are mixed and the valuable element V is recovered by water extraction process.

[0089] Specifically, the principle for calculating and incorporating the carbonaceous reducing agent in S1 is as follows: all iron oxides are reduced to Fe, all TiO2 is reduced to Ti2CO, SiO2 is partially reduced to form an Fe-2%Si alloy, all V2O5 is reduced to V, all Cr2O3 is reduced to Cr, all ZnO is reduced to Zn, and all MnO is reduced to Mn. If the carbonaceous reducing agent used is not high-purity graphite, the ash content and composition of the carbonaceous reducing agent must be considered in the calculation.

[0090] Specifically, the additive in S2 is borax, with an addition amount of 0.1-1%; the pellet size is 3-30mm;

[0091] Reduction is performed under vacuum at a temperature of 800-1400℃ and a vacuum level of 10. -4 -10 4 Pa; or reduction under argon atmosphere, with argon content ≥80%, the remainder being CO and H2, and no O2 or CO2, reduction temperature 1100-1700℃; reduction time 2-10h; reduction under vacuum or argon atmosphere, the resulting mixed product is Fe(V) alloy-Ti(C,O)-MOx;

[0092] Alternatively, reduction can be carried out under nitrogen atmosphere with nitrogen content ≥65%, the remainder being CO and H2, and no O2 or CO2 present. The reduction temperature is 900-1500℃, and the reduction time is 2-10h. The resulting mixed product is Fe(V) alloy-Ti(C,N,O)-MOx.

[0093] Specifically, in S3, the crushing and grinding process separates the Fe(V) alloy and Ti(C,N,O) / Ti(C,O)-MOx in the mixed product at the microscale, with a fine grinding particle size of <50μm; the magnetic field strength for magnetic separation is 800-1800GS.

[0094] Specifically, the hydrochloric acid leaching in S4 has an acid mass concentration of 3-30%, a liquid-to-solid ratio of 5-50 ml / g, a leaching time of 0.5-2 h, and a leaching temperature of 20-90℃. To improve the leaching effect, appropriate stirring or ultrasonic assistance is used. The titanium-rich material obtained by filtration and separation has a main component of Ti(C, N, O) / Ti(C, O)>80%, Fe<1%, and the remainder is MOx. The filtrate contains FeCl2, a small amount of V, and impurities such as Ca, Mg, Al, Cr, Zn, Mn, Cu, and Pb.

[0095] Specifically, in S4, when using the soluble anodic electrolysis method to prepare metallic titanium, the titanium-rich material must first be processed to a density ≥ 4.5 g / cm³. 3 High-density, high-strength anode blocks are preferably processed using hot pressing sintering, hot isostatic pressing sintering, or high-temperature casting; electrolysis is performed on a single Ti oxide containing 1-6% Ti. 2+ or Ti 3+ The reaction is carried out in a molten salt of chloride / fluoride ions, with a cathode current density of 0.1-0.5 A / cm². 2 Anode current density: 0.01-0.2 A / cm² 2 (Single Ti) 2+ (time) or 0.2-0.5 A / cm 2 (Single Ti) 3+ (Time); after every 30-40 hours of electrolysis, the molten salt needs to be purified by pre-electrolysis or by introducing HCl / Cl2 (chloride molten salt) or HF / F2 (fluoride molten salt).

[0096] Alternatively, when using a low-temperature chlorination method, argon / nitrogen gas preheated to 250-300℃ is used as the carrier gas. The titanium-rich powder is injected into the reaction zone from the side and moves downward under gravity. Chlorine gas preheated to 250-300℃, or a mixture of chlorine and argon / nitrogen, enters the reaction zone from the bottom and moves upward. It reacts with the downward-moving titanium-rich powder and releases heat of reaction. The released heat of reaction will raise the temperature of the reaction zone, which needs to be controlled at 300-500℃. The pressure in the lower part of the reaction zone is 1-3 atm (of which the partial pressure of chlorine is ≥20%), and the pressure in the upper part is 0.8-1 atm, with the pressure difference between the upper and lower parts maintained at ≥0.2 atm. The mixed gas after the reaction, along with the flue gas, is discharged from the upper part of the reaction zone. After dust collection, condensation, and purification, TiCl4 is obtained.

[0097] Specifically, in the low-temperature chlorination process, the gas is preheated using the heat of reaction released by the chlorination reaction. Specifically, the gas at a temperature of <250°C is used to cool the reaction zone, and the excess heat of reaction is absorbed through heat conduction. While controlling the temperature of the reaction zone at 300-500°C, the gas is preheated.

[0098] Specifically, the melting and casting of magnetic materials in S5 is carried out in vacuum equipment with stirring function, such as mechanically stirred vacuum melting furnace, gas-blown stirred vacuum melting furnace, vacuum induction melting furnace, vacuum suspension melting furnace, etc., with a vacuum degree of 10. -3 -10 2 Pa, melting temperature 1550-1750℃, stirring for 30-90 minutes before casting, the purpose of which is to preliminarily refine the melt through vacuum stirring, removing gaseous and volatile impurity elements such as C, P, S, N, Pb, Zn, Mn, Ca, Mg, etc.

[0099] Specifically, S6 contains Fe 2+ The purification of acid solutions is achieved by recovering V and removing impurities such as Ca, Mg, Al, Cr, Zn, Mn, Cu, and Pb; the purification process needs to be tailored to the Fe content. 2+ The concentration of volatile organic compound (V) in the acid solution is selected based on the following: when V concentration > 0.2 g / L, the "NaF precipitation - ion exchange resin adsorption - extraction" process is selected; when V concentration < 0.2 g / L, the "NaF precipitation - strong acid cation exchange resin adsorption - electrolysis" process is selected. Inert gas protection is used throughout the purification process to avoid Fe... 2+ Oxidized to Fe 3+ .

[0100] Specifically, in the S5 process, the electrolytic refining of high-purity iron requires adjustment of the Fe electrolyte. 2+ The concentration is 0.2-1.2 mol / L, pH value is 1-3, and the adjustment method is to add FeCl2 and sodium carbonate / sodium bicarbonate; the electrolysis temperature is 40-60℃, and the current density is 50-300 A / m. 2 The electrodes should be replaced every 20-60 hours of electrolysis. The electrolyte should be circulated during electrolysis at a flow rate of 2-3 L / min. Before re-entering the electrolytic cell, the circulating electrolyte must be treated according to the Fe content. 2+ The acid solution is purified using purification methods.

[0101] Specifically, during the electrolytic refining process in S5 to prepare high-purity iron, 0.5-1.5 g / L of ascorbic acid is added to the purified electrolyte to inhibit the formation of Fe during electrolysis. 3+ Add 0.05-0.5% isooctyl alcohol and 2-6 g / L sodium fluoride to promote the aggregation and precipitation of V, Al, Si and other impurities dissolved in the anode into the anode mud. To avoid excessive anode mud affecting the electrolysis process, the anode mud should be cleaned every 6-10 hours.

[0102] Specifically, the utilization rates of titanium, iron, and vanadium in the efficient comprehensive utilization method of vanadium-titanium magnetite are 75% (sponge titanium)-80% (titanium dioxide), ≥71% (high-purity iron), and ≥61% (vanadium pentoxide), respectively.

[0103] In particular, a highly efficient comprehensive utilization method for vanadium-titanium magnetite is also suitable for the comprehensive utilization of other titanium-containing minerals such as rutile, high-titanium slag, sea sand, high-titanium blast furnace slag from the blast furnace-converter process, and titanium-containing slag from the direct reduction-electric furnace smelting process.

[0104] Example 1

[0105] This embodiment provides a method for the efficient comprehensive utilization of vanadium-titanium magnetite, which includes the following steps:

[0106] S1. Selection of raw materials and preparation of carbonaceous reducing agent: Titanium concentrate obtained from vanadium-titanium magnetite ore after beneficiation is used as raw material. The composition of titanium concentrate by mass percentage is: Fe2O3 24.06%, FeO 6.11%, TiO2 52.96%, V2O5 0.20%, Cr2O3 2.25%, MnO 1.91%, ZnO 0.06%, SiO2 6.29%, CaO 0.18%, MgO 0.22%, Al2O3 2.15%. Based on the composition and content of the titanium concentrate raw material, the carbonaceous reducing agent is calculated and prepared. SiO2 is only partially reduced to Fe-2%Si alloy. It is calculated that 23.65g of carbon is required for every 100g of titanium concentrate. The titanium concentrate is thoroughly mixed with 99% high-purity graphite powder.

[0107] S2, Pellet Preparation and Carbothermic Reduction: 0.5% borax was added to the concentrate and carbonaceous reducing agent after thorough mixing in S1 and mixed evenly to form pellets with an average size of 20 mm; then, the pellets were reduced in pure nitrogen at 1400 °C for 3 h to obtain a mixed product of Fe alloy-Ti(C, N, O)-MOx.

[0108] S3. Crushing, Fine Grinding, and Magnetic Separation: The mixture from S2 is crushed and finely ground to obtain a finely ground mixture with a particle size of less than 48 micrometers. This mixture is then separated using a counter-current wet magnetic separation process with a magnetic field strength of 1200 GS to obtain non-magnetic materials (XRD patterns of the non-magnetic materials are shown in the image). Figure 2 (as shown) and magnetic materials (XRD patterns of magnetic materials are shown) Figure 3 (As shown); the non-magnetic material is mainly a mixture of Ti(C, N, O)-MOx, and the magnetic material is mainly an Fe alloy;

[0109] The composition of the non-magnetic materials is shown in Table 1 below:

[0110] Table 1. Composition of the non-magnetic product in Example 1 (unit: wt.%)

[0111]

[0112] The composition of the magnetic material is shown in Table 2 below:

[0113] Table 2. Composition of the magnetic product in Example 1 (unit: wt.%)

[0114]

[0115] S4. Treatment of non-magnetic materials: The non-magnetic materials of S3 were leached with 10wt.% hydrochloric acid at 25℃ with stirring. The liquid-to-solid ratio during leaching was 10ml / g, and the leaching time was 1h. After leaching, the materials were separated by filtration to obtain titanium-rich materials and Fe-containing materials. 2+ The acid solution contained 83.92 wt.% Ti (C, N, O) in the titanium-rich material, with a FeCl2 concentration of 0.08 mol / L, a V concentration of 0.09 g / L, and a pH value <1. The obtained titanium-rich material was then used to prepare metallic titanium via soluble anodic electrolysis. During preparation, the titanium-rich material was first processed into a density of 4.6 g / cm³ by hot pressing and sintering. 3 The anode, then containing 5% single Ti 3+ Electrolysis was performed in a NaCl-KCl based molten salt containing ions, with both the cathode and anolyte current densities being 0.3 A / cm². 2 The electrolysis time was 30 hours. After the electrolysis was completed, the cathode product was peeled off and cleaned, and the analysis showed that it was metallic titanium with a purity of >99%.

[0116] S5. Processing of magnetic materials: The magnetic materials from S3 are melted in a vacuum induction furnace and cast into crude iron ingots. The vacuum degree of the melting process is 10. -3 Pa, melting temperature 1600℃, melting time 45min;

[0117] The Fe-containing part in step S4 2+ The acid solution was purified using a process of "NaF precipitation - strong acid cation exchange resin adsorption - electrolysis", and then FeCl2 was added to adjust the Fe content. 2+ The concentration was adjusted to 0.8 mol / L, and sodium carbonate was added to adjust the pH to 2. Then, 1 g / L ascorbic acid, 0.2% isooctyl alcohol, and 3 g / L sodium fluoride were added. Using the crude iron as the anode and the titanium plate as the cathode, the mixture was subjected to an induction heating at 50°C and a current density of 200 A / m. 2 Electrolysis was carried out for 30 hours. After electrolysis, the cathode product was stripped off and repeatedly ultrasonically cleaned with pure water. Analysis showed that it was high-purity iron with a purity of 99.99%.

[0118] S6 and V recycling: S5 containing Fe... 2+ The resin-adsorbed desorbate during the acid purification process is desorbed, and the vanadium concentration is concentrated to 5-10 times the original concentration. Then, it is processed in a diaphragm electrolyzer at 30 mA / cm². 2 Electrolysis at a current density yielded V2O5 with a purity >98% at the cathode;

[0119] The anode mud generated during the electrolysis of high-purity iron in S5 is collected, and then subjected to alkaline leaching-oxidation or sodium roasting-leaching, followed by the addition of ammonium salt precipitation and calcination to obtain V2O5 with a purity >98%.

[0120] In this embodiment, the utilization rates of titanium, iron, and vanadium in the efficient comprehensive utilization method of vanadium-titanium magnetite are 84%, 71%, and 61%, respectively.

[0121] Comparative Example 1

[0122] The technical content of Comparative Example 1 differs from that of Example 1 in that borax is not added in step S3. All other operating steps and parameters are the same as in Example 1.

[0123] In Comparative Example 1, the main components of the non-magnetic material obtained by S3 magnetic separation and their comparison with Example 1 are shown in Table 3.

[0124] Table 3 Comparison of the main components of the non-magnetic materials in Example 1 and Comparative Example 1

[0125]

[0126] As can be seen, the total Fe content in the non-magnetic material obtained by S3 magnetic separation in Comparative Example 1 is as high as 11.02%, and the total Fe content is still 1.88% after acid leaching. However, the Ti (C, N, O) content in the titanium-rich material after acid leaching is only 78.56%, which is lower than 83.92% in Example 1.

[0127] The results of Comparative Example 1 show that without the addition of borax, the separation effect of titanium and iron is poor. Although the effect of poor magnetic separation can be mitigated to some extent by acid leaching, the acid leaching effect is not thorough and reduces the Ti content in the titanium-rich material.

[0128] As can be seen from Example 1 and Comparative Example 1, the method of promoting the aggregation and growth of the metallic Fe phase during the reduction process of the present invention helps to achieve the formation of microstructures that facilitate the separation of titanium and iron in the raw materials, thereby achieving selective and efficient separation of titanium and iron.

[0129] Example 2

[0130] This embodiment provides a method for the efficient comprehensive utilization of vanadium-titanium magnetite, which includes the following steps:

[0131] S1. Selection of raw materials and preparation of carbonaceous reducing agent: Foreign sea sand ore is used as raw material. The composition of sea sand ore by mass percentage is: Fe2O3 50.53%, FeO 25.82%, TiO2 11.88%, V2O5 0.78%, Cr2O3 0.05%, MnO 0.54%, ZnO 0.07%, SiO2 4.19%, CaO 0.14%, MgO 2.14%, Al2O3 3.60%. Based on the composition and content of the aforementioned sea sand ore raw material, the carbonaceous reducing agent is calculated and prepared. SiO2 is only partially reduced to Fe-2%Si alloy. It is calculated that 20.63g of carbon is required for every 100g of sea sand ore. The sea sand ore is thoroughly mixed with 99% graphite powder.

[0132] S2, Pellet Preparation and Carbothermic Reduction: In the thoroughly mixed sea sand ore and carbonaceous reducing agent of S1, 1.0% borax is added and mixed evenly to form pellets with an average size of 20 mm; then, at 10... -1 The Fe alloy-Ti(C,O)-MOx mixed product was obtained by reducing Pa in vacuum at 1300℃ for 3h.

[0133] S3, Crushing, Fine Grinding and Magnetic Separation: The mixed product of S2 is crushed and finely ground to obtain a finely ground mixture with a particle size of less than 48 micrometers; then the finely ground mixture is separated by countercurrent wet magnetic separation with a magnetic field strength of 1200GS to obtain non-magnetic and magnetic materials; the non-magnetic material is mainly a mixture of Ti(C,O)-MOx, and the magnetic material is mainly Fe alloy.

[0134] The composition of the non-magnetic materials is shown in Table 4 below:

[0135] Table 4. Composition of the non-magnetic product in Example 2 (unit: wt.%)

[0136]

[0137] The composition of the magnetic material is shown in Table 5 below:

[0138] Table 5. Composition of the magnetic product in Example 2 (unit: wt.%)

[0139]

[0140] S4. Treatment of non-magnetic materials: The non-magnetic materials of S3 were leached with 30wt.% hydrochloric acid at 60℃ with stirring. The liquid-to-solid ratio during leaching was 10ml / g, and the leaching time was 1h. After leaching, the materials were separated by filtration to obtain titanium-rich materials and Fe-containing materials. 2+The acid solution contains 56.63 wt.% Ti(C, O) in the titanium-rich material (the remainder mainly consists of SiO2, Al2O3, and small amounts of CaO and MgO), with a FeCl2 concentration of 0.1 mol / L, a V concentration of 0.96 g / L, and a pH value <1. The obtained titanium-rich material is then used to prepare TiCl4 via a low-temperature chlorination method. During preparation, nitrogen gas preheated to 300°C is used as the carrier gas to blow the titanium-rich material powder into the reaction zone from the side, where it moves downwards under gravity. Simultaneously, pure chlorine gas preheated to 300°C is introduced into the reaction zone from the bottom and moves upwards. Upon contact, the two gases immediately react and release heat, raising the temperature of the reaction zone to 450°C. The pressure at the bottom is controlled at 2 atm, and the pressure at the top at 1 atm. The resulting mixture of gas and dust is discharged from the top of the reaction zone. After dust collection, condensation, and refining, TiCl4 is obtained and used to prepare titanium dioxide.

[0141] It should be noted that in this Example 2, due to the composition of the raw material sea sand, the content of Ti (C, O) in the titanium-rich material in S4 is low, and the rest is mainly SiO2 and Al2O3. However, SiO2 and Al2O3 do not undergo chlorination reaction in the low-temperature chlorination process without adding carbon, so they have almost no effect on the low-temperature chlorination process of the titanium-rich material.

[0142] S5. Processing of magnetic materials: The magnetic materials from S3 are melted in a vacuum induction furnace and cast into crude iron ingots. The vacuum degree of the melting process is 10. -3 Pa, melting temperature 1600℃, melting time 45min;

[0143] The Fe-containing part in step S4 2+ The acid solution was purified using a process of "NaF precipitation-ion exchange resin adsorption-extraction" and then FeCl2 was added to adjust the Fe content. 2+ The concentration was adjusted to 0.8 mol / L, and sodium carbonate was added to adjust the pH to 2. Then, 1 g / L ascorbic acid, 0.2% isooctyl alcohol, and 3 g / L sodium fluoride were added. Using the crude iron as the anode and the titanium plate as the cathode, the mixture was subjected to an experiment at 50°C and a current density of 200 A / m. 2 Electrolysis was carried out for 30 hours. After electrolysis, the cathode product was stripped off and repeatedly ultrasonically cleaned with pure water. Analysis showed that it was high-purity iron with a purity of 99.99%.

[0144] S6 and V recycling: S5 containing Fe... 2+ The resin adsorbed desorbate during the acid purification process is desorbed, and / or the extracted organic phase is back-extracted. The eluent and back-extract are treated to enrich and precipitate V, resulting in vanadium-containing slag. The anode mud generated during the electrolysis of high-purity iron in S5 is collected. The above-mentioned vanadium-containing slag and vanadium-containing anode mud are mixed and subjected to alkaline leaching-oxidation or sodium roasting-leaching. After adding ammonium salt for precipitation and calcination, V2O5 with a purity >98% can be obtained.

[0145] The utilization rates of titanium, iron, and vanadium in the efficient comprehensive utilization method of vanadium-titanium magnetite in this embodiment are 79%, 76%, and 63%, respectively. The results of this embodiment demonstrate that the technology of the present invention is also applicable to other titanium-bearing minerals.

[0146] Comparative Example 2

[0147] The technical difference between Comparative Example 2 and Example 2 is that, in S4, the carrier gas nitrogen and the reaction gas chlorine for conveying the titanium-rich material are not preheated and enter the reaction zone directly at room temperature; since the titanium-rich material does not react with chlorine at room temperature, the temperature of the reaction zone is first raised to 450°C by external heating during chlorination. Other operating steps and parameters are the same as in Example 2.

[0148] In Comparative Example 2, if external heating is maintained during the chlorination process of S4, the heat of reaction released by the chlorination reaction will raise the temperature of the reaction zone to 600-650℃. At this time, although the furnace charge sintering phenomenon will not occur because the titanium-rich material is in powder form, the chlorination rate of SiO2, Al2O3 and other raw materials will increase, reducing the purity of the product TiCl4 and increasing chlorine consumption.

[0149] In Comparative Example 2, during the chlorination process of S4, if the external heating is removed after the chlorination reaction begins, the heat of reaction released by the chlorination reaction is absorbed by the supercooled carrier gas, chlorine gas and titanium-rich material, causing the temperature of the reaction zone to drop to 300-350℃. At this time, although the chlorination reaction can still proceed, the chlorination reaction rate and efficiency are reduced.

[0150] As can be seen from Example 2 and Comparative Example 2, the chlorination reaction using the preheated carrier gas and chlorine gas of the present invention can improve the chlorination effect without the need for external heating assistance. At the same time, it can also use the carrier gas and chlorine gas to absorb excess reaction heat, control and stabilize the chlorination temperature, so that the chlorination reaction process can proceed stably and continuously, reduce energy consumption and improve efficiency.

[0151] Example 3

[0152] This embodiment provides a method for the efficient comprehensive utilization of vanadium-titanium magnetite, which includes the following steps:

[0153] S1. Selection of raw materials and preparation of carbonaceous reducing agent: Iron concentrate obtained from vanadium-titanium magnetite ore after beneficiation is used as raw material. The composition of the iron concentrate by mass percentage is: Fe2O3 43.9%, FeO 30.1%, TiO2 11.5%, V2O5 0.7%, SiO2 5.3%, CaO 0.6%, MgO 4.4%, Al2O3 4.3%. Based on the composition and content of the iron concentrate raw material, the carbonaceous reducing agent is calculated and prepared. SiO2 is only partially reduced to Fe-2%Si alloy. It is calculated that 19.54g of carbon is required for every 100g of iron concentrate. The iron concentrate is thoroughly mixed with 99% graphite powder.

[0154] S2, Pellet Preparation and Carbothermic Reduction: 1.0% borax was added to the thoroughly mixed iron concentrate and carbonaceous reducing agent after S1 and mixed evenly to form pellets with an average size of 20 mm; then the pellets were reduced at 1600 °C for 3 h in pure argon to obtain a mixed product of Fe alloy-Ti(C,O)-MOx.

[0155] S3, Crushing, Fine Grinding and Magnetic Separation: The mixed product of S2 is crushed and finely ground to obtain a finely ground mixture with a particle size of less than 48 micrometers; then the finely ground mixture is separated by countercurrent wet magnetic separation with a magnetic field strength of 1000GS to obtain non-magnetic and magnetic materials; the non-magnetic material is mainly a mixture of Ti(C,O)-MOx, and the magnetic material is mainly Fe alloy.

[0156] The composition of the non-magnetic materials is shown in Table 6 below:

[0157] Table 6. Composition of the non-magnetic product in Example 3 (unit: wt.%)

[0158]

[0159] The composition of the magnetic material is shown in Table 7 below:

[0160] Table 7. Composition of the magnetic product in Example 3 (unit: wt.%)

[0161]

[0162] S4. Treatment of non-magnetic materials: The non-magnetic materials of S3 were leached with 30wt.% hydrochloric acid at 25℃ with stirring. The liquid-to-solid ratio during leaching was 10ml / g, and the leaching time was 1h. After leaching, the materials were separated by filtration to obtain titanium-rich materials and Fe-containing materials. 2+The acid solution contains 50.19 wt.% Ti(C, O) in the titanium-rich material (the remainder being CaO, MgO, SiO2, and Al2O3), with a FeCl2 concentration of 0.19 mol / L, a V concentration of 0.72 g / L, and a pH value <1. The obtained titanium-rich material is then used to prepare TiCl4 via a low-temperature chlorination method. During preparation, nitrogen gas preheated to 300°C is used as the carrier gas to blow the titanium-rich material powder into the reaction zone from the side, where it moves downwards under gravity. Simultaneously, pure chlorine gas preheated to 300°C is introduced into the reaction zone from the bottom and moves upwards. Upon contact, the two gases immediately react and release heat, raising the temperature of the reaction zone to 450°C. The pressure at the bottom is controlled at 2 atm, and the pressure at the top at 1 atm. The resulting mixture of gas and dust is discharged from the top of the reaction zone. After dust collection, condensation, and refining, TiCl4 is obtained and used to prepare sponge titanium.

[0163] S5. Processing of magnetic materials: The magnetic materials from S3 are smelted in a vacuum levitation melting furnace and cast into crude iron ingots. The vacuum degree of the melting process is 10. -3 Pa, melting temperature 1600℃, melting time 45min;

[0164] The Fe-containing part in step S4 2+ The acid solution was purified using a process of "NaF precipitation-ion exchange resin adsorption-extraction" and then FeCl2 was added to adjust the Fe content. 2+ The concentration was adjusted to 0.8 mol / L, and sodium carbonate was added to adjust the pH to 2. Then, 1 g / L ascorbic acid, 0.2% isooctyl alcohol, and 3 g / L sodium fluoride were added. Using the crude iron as the anode and the titanium plate as the cathode, the mixture was subjected to an experiment at 50°C and a current density of 200 A / m. 2 Electrolysis was carried out for 30 hours. After electrolysis, the cathode product was stripped off and repeatedly ultrasonically cleaned with pure water. Analysis showed that it was high-purity iron with a purity of 99.99%.

[0165] S6 and V recycling: S5 containing Fe... 2+ The resin adsorbed desorbate during the acid purification process is desorbed, and / or the extracted organic phase is back-extracted. The eluent and back-extract are treated to enrich and precipitate V, resulting in vanadium-containing slag. The anode mud generated during the electrolysis of high-purity iron in S5 is collected. The above-mentioned vanadium-containing slag and vanadium-containing anode mud are mixed and subjected to alkaline leaching-oxidation or sodium roasting-leaching. After adding ammonium salt for precipitation and calcination, V2O5 with a purity >98% can be obtained.

[0166] In this embodiment, the utilization rates of titanium, iron, and vanadium in the efficient comprehensive utilization method of vanadium-titanium magnetite are 75%, 75%, and 62%, respectively.

[0167] The above-described scheme, the present invention, is a highly efficient comprehensive utilization method for vanadium-titanium magnetite with titanium extraction as the core. Using concentrate from vanadium-titanium magnetite ore as raw material, non-magnetic Ti(C,N,O) / Ti(C,O)-MOx and magnetic Fe(V) are obtained through selective carbothermal reduction-magnetic separation. The non-magnetic material is leached with hydrochloric acid to obtain titanium-rich material, which is then electrolyzed with a soluble anode to prepare metallic titanium, or chlorinated at low temperature to TiCl4. The magnetic material, after smelting and purification, is used as the anode, and the purified Fe-containing material is then subjected to hydrochloric acid leaching. 2+ High-purity iron is prepared by electrolytic refining in acid solution; vanadium is enriched and recovered in the purification of vanadium-containing slag and electrolytic refining anode mud.

[0168] The process flow of this invention fully considers the physicochemical properties of waste residue, waste acid, and waste heat generated in each stage, achieving recycling and reducing emissions while improving the comprehensive utilization rate of valuable elements. Compared with the existing blast furnace-converter process with titanium utilization rates of 12% (sponge titanium)-18% (titanium dioxide), iron utilization rate of 80% (semi-steel), and vanadium utilization rate of 39% (vanadium pentoxide), and the direct reduction-electric furnace melting process with titanium utilization rates of 70% (sponge titanium)-75% (titanium dioxide), iron utilization rate of 90% (semi-steel), and vanadium utilization rate of 50% (vanadium pentoxide), the present invention achieves titanium utilization rates of 75% (sponge titanium)-80% (titanium dioxide), iron utilization rate of ≥71% (high-purity iron), and vanadium utilization rate of ≥61% (vanadium pentoxide). The utilization rates of titanium and vanadium are improved to varying degrees. Although the iron utilization rate is somewhat reduced, its product is 99.99% high-purity iron, which is nearly 100 times more expensive than semi-steel. The high added value is enough to compensate for the adverse effects of the reduced utilization rate.

[0169] This invention provides a highly efficient comprehensive utilization method for vanadium-titanium magnetite. During the low-temperature chlorination process of titanium-rich materials, the titanium-rich materials move counter-currently with Cl2, fully utilizing the characteristics of Ti(C,N,O) / Ti(C,O) chlorination—low temperature, short reaction time, and high efficiency. The chlorination process requires no carbon addition and no need to maintain a reducing atmosphere, effectively saving raw materials compared to existing flash suspension chlorination methods. The carrier gas and chlorine absorb excess reaction heat, stabilizing the chlorination temperature while preheating the materials, allowing for a more complete chlorination reaction and increasing the chlorination rate. The titanium-rich materials do not agglomerate; they are dispersed in powder form and react with chlorine, increasing the contact area and making the reaction faster than with boiling chlorination. Furthermore, the reaction heat is further dispersed, avoiding technical problems such as furnace charge sintering caused by localized overheating during the chlorination process, which are present in existing low-temperature boiling chlorination methods.

[0170] In summary, compared with other traditional methods, the method of this invention synergistically improves the utilization rate of titanium, iron and vanadium through the selection of raw materials and the addition of carbonaceous reducing agents, pellet preparation and carbothermic reduction, crushing and fine grinding and magnetic separation, treatment of non-magnetic materials, treatment of magnetic materials, and recycling of V. This method does not require slag production, avoiding various problems caused by large slag volume in traditional processes. The process is simple, energy-efficient, highly controllable, and environmentally friendly, which is conducive to large-scale industrial production and promotion.

[0171] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0172] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0173] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0174] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for the efficient comprehensive utilization of vanadium-titanium magnetite, characterized in that, The efficient and comprehensive utilization method of the vanadium-titanium magnetite is as follows: S1. Selection of raw materials and preparation of carbonaceous reducing agent: The raw materials are titanium concentrate, vanadium-titanium magnetite concentrate, or a mixture of both in any proportion, obtained from beneficiation of vanadium-titanium magnetite ore. Based on the composition and content of the concentrate raw materials, the carbonaceous reducing agent is calculated and prepared according to specific principles, and the concentrate and carbonaceous reducing agent are thoroughly mixed. The principles for calculating and preparing the carbonaceous reducing agent are as follows: all iron oxides are reduced to Fe, all TiO2 is reduced to Ti2CO, SiO2 is partially reduced to form a Fe-2%Si alloy, all V2O5 is reduced to V, all Cr2O3 is reduced to Cr, all ZnO is reduced to Zn, and all MnO is reduced to Mn. If the carbonaceous reducing agent used is not high-purity graphite, the ash content and composition of the carbonaceous reducing agent must be considered during the calculation. S2, Pellet Preparation and Carbothermic Reduction: A small amount of additives are added to the concentrate and carbonaceous reducing agent after thorough mixing in S1 and mixed evenly to form pellets; then selective carbothermic reduction is carried out in vacuum, argon or nitrogen atmosphere to obtain FeV alloy-Ti(C,N,O) / Ti(C,O)-MOx mixed product; S3, Crushing, Fine Grinding and Magnetic Separation: The mixed product of S2 is crushed and finely ground to obtain a finely ground mixture; then the finely ground mixture is separated by countercurrent wet magnetic separation to obtain non-magnetic and magnetic materials; the non-magnetic material is mainly a mixture of Ti(C,N,O) / Ti(C,O)-MOx, and the magnetic material is mainly FeV alloy; S4. Treatment of non-magnetic materials: The non-magnetic materials of S3 are leached with hydrochloric acid, and then filtered and separated to obtain titanium-rich materials and Fe-containing materials. 2+ Acid solution; during the selective reduction process, unreacted vanadium compounds dissolve into the Fe-containing solution during hydrochloric acid leaching. 2+ Acid; There are two ways to utilize titanium-rich materials: one is to directly prepare metallic titanium using a soluble anodic electrolysis method; the other is to chlorinate it at low temperature to TiCl4, and then prepare it into sponge titanium or titanium dioxide. The titanium-rich material obtained by filtration and separation mainly consists of Ti(C, N, O) / Ti(C, O) > 80%, Fe < 1%, and the remainder is MOx; the filtrate contains FeCl2, a small amount of V, and impurities such as Ca, Mg, Al, Cr, Zn, Mn, Cu, and Pb. S5. Treatment of magnetic materials: The magnetic materials from S3 are melted and cast into crude iron anode plates, and the purified Fe-containing materials from S4 are used as the anode plates. 2+ The acid solution is used as the electrolyte, and electrolytic refining is used to prepare high-purity iron with a purity ≥99.99%; containing Fe 2+ V in acidic solutions is enriched in vanadium-containing slag during purification; V in magnetic materials is enriched in vanadium-containing anode mud during electrolytic refining. S6 and V recycling: The vanadium-containing slag and vanadium-containing anode mud of S5 are mixed and the valuable element V is recovered by water extraction process.

2. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 1, characterized in that, The additive in S2 is borax, with an addition amount of 0.1-1%; the pellet size is 3-30mm. Reduction under vacuum, at a reduction temperature of 800-1400℃ and a vacuum degree of 10. -4 -10 4 Pa; or reduction under argon atmosphere, with argon content ≥80%, the remainder being CO and H2, and no O2 or CO2, reduction temperature 1100-1700℃; reduction time 2-10h; reduction under vacuum or argon atmosphere, the resulting mixed product is FeV alloy-Ti(C,O)-MOx; Alternatively, reduction can be carried out under nitrogen atmosphere with nitrogen content ≥65%, the remainder being CO and H2, and no O2 or CO2 present. The reduction temperature is 900-1500℃, and the reduction time is 2-10h. The resulting mixed product is FeV alloy-Ti(C,N,O)-MOx.

3. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 1, characterized in that, In S3, crushing and grinding separates the FeV alloy and Ti(C,N,O) / Ti(C,O)-MOx in the mixed product at the microscale, with a fine grinding particle size of <50μm; the magnetic field strength for magnetic separation is 800-1800GS.

4. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 1, characterized in that, The hydrochloric acid leaching process in S4 has an acid concentration of 3-30%, a liquid-to-solid ratio of 5-50 ml / g, a leaching time of 0.5-2 h, and a leaching temperature of 20-90℃. To improve the leaching effect, stirring or ultrasonic assistance is used.

5. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 1, characterized in that, When preparing metallic titanium using the soluble anodic electrolysis method in S4, the titanium-rich material must first be processed to a density ≥ 4.5 g / cm³. 3 High-density, high-strength anode blocks are processed using methods including hot pressing sintering, hot isostatic pressing sintering, or high-temperature casting; electrolysis is carried out on a single Ti oxide containing 1-6% Ti. 2+ or Ti 3+ The reaction is carried out in a molten salt of chloride / fluoride ions, with a cathode current density of 0.1-0.5 A / cm². 2 Anode current density single Ti 2+ The current is 0.01-0.2 A / cm. 2 or a single Ti 3+ The current is 0.2-0.5 A / cm. 2 Every 30-40 hours of electrolysis, the molten salt is purified. For chloride molten salt, the method is pre-electrolysis or introduction of HCl / Cl2; for fluoride molten salt, the method is introduction of HF / F2. Alternatively, when using a low-temperature chlorination method, argon / nitrogen gas preheated to 250-300℃ is used as the carrier gas. The titanium-rich powder is injected into the reaction zone from the side and moves downward under gravity. Chlorine gas preheated to 250-300℃, or a mixture of chlorine and argon / nitrogen, enters the reaction zone from the bottom and moves upward. It reacts with the downward-moving titanium-rich powder and releases heat of reaction. The released heat of reaction raises the temperature of the reaction zone, which is controlled at 300-500℃. The pressure in the lower part of the reaction zone is 1-3 atm, with chlorine partial pressure accounting for ≥20%, and the pressure in the upper part is 0.8-1 atm, with the pressure difference between the upper and lower parts maintained at ≥0.2 atm. The mixed gas after the reaction, along with the flue gas, is discharged from the upper part of the reaction zone. After dust collection, condensation, and purification, TiCl4 is obtained.

6. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 5, characterized in that, In the low-temperature chlorination process, the gas is preheated using the heat of reaction released by the chlorination reaction. Specifically, the gas at a temperature of <250°C is used to cool the reaction zone, and the excess heat of reaction is absorbed through heat conduction. While controlling the temperature of the reaction zone at 300-500°C, the gas is preheated.

7. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 1, characterized in that, The melting and casting of the magnetic material in S5 is carried out in a vacuum device with a stirring function, at a vacuum level of 10. -3 -10 2 Pa, melting temperature 1550-1750℃, stirring for 30-90 minutes before casting, the purpose of which is to refine the melt through vacuum stirring and remove gaseous and volatile impurity elements.

8. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 1, characterized in that, S5 contains Fe 2+ The purification of acid solutions is achieved by recovering V and removing impurities such as Ca, Mg, Al, Cr, Zn, Mn, Cu, and Pb; the purification process needs to be tailored to the Fe content. 2+ The concentration of volatile organic compound (V) in the acid solution is selected based on the following: when V concentration > 0.2 g / L, the "NaF precipitation - ion exchange resin adsorption - extraction" process is selected; when V concentration < 0.2 g / L, the "NaF precipitation - strong acid cation exchange resin adsorption - electrolysis" process is selected. Inert gas protection is used throughout the purification process to avoid Fe... 2+ Oxidized to Fe 3+ .

9. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 8, characterized in that, In S5 electrolytic refining to produce high-purity iron, the Fe content of the electrolyte needs to be adjusted. 2+ The concentration is 0.2-1.2 mol / L, pH value is 1-3, and the adjustment method is to add FeCl2 and sodium carbonate / sodium bicarbonate; the electrolysis temperature is 40-60℃, and the current density is 50-300 A / m. 2 The electrodes should be replaced every 20-60 hours of electrolysis. The electrolyte should be circulated during electrolysis at a flow rate of 2-3 L / min. Before re-entering the electrolytic cell, the circulating electrolyte should be adjusted according to its Fe content. 2+ The acid solution is purified using purification methods.

10. The method for efficient comprehensive utilization of vanadium-titanium magnetite according to claim 8, characterized in that, In the electrolytic refining process for preparing high-purity iron, 0.5-1.5 g / L of ascorbic acid is added to the electrolyte to inhibit the formation of Fe during electrolysis. 3+ Add 0.05-0.5% isooctyl alcohol and 2-6 g / L sodium fluoride to promote the aggregation and precipitation of V, Al, and Si impurities dissolved in the anode into the anode mud. To avoid excessive anode mud affecting the electrolysis process, the anode mud should be cleaned every 6-10 hours.

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