WO2019137544A1 - Method for extracting valent component in vanadium titanium magnetite by means of oxygen-rich selective leaching - Google Patents

Abstract

A method for extracting valent components in vanadium titanium magnetite by means of oxygen-rich selective leaching, comprising the steps of: (1) crushing vanadium titanium magnetite, placing same and a sodium hydroxide solution into an autoclave, introducing oxygen gas, stirring at an elevated temperature, and maintaining the temperature to complete alkali leaching; (2) filtering and separating the alkali leached material, and washing the alkali decomposition product with water to prepare an alkali decomposition slag; (3) adding an ammonium salt to the alkali leached liquid, standing and precipitating the alkali leached liquid, and drying and calcining the solid phase to form vanadium oxide; (4) adding the alkali decomposition slag and hydrochloric acid to an autoclave, adding a crystal seed, stirring at an elevated temperature and maintaining the temperature to complete acid leaching and hydrolysis; (5) performing filtration and separation, washing the hydrolysate with water, drying same, and then calcining same to form titanium oxide. The method achieves the recycling of resources and does not produce industrial waste water and waste slag to achieve green production; and achieves green recycling, saves energy and reduces emissions..

Description

Method for extracting valuable components in vanadium-titanium magnetite by oxygen-rich selective leaching Technical field

The invention belongs to the technical field of non-ferrous metallurgy, and particularly relates to a method for extracting valuable components in vanadium-titanium magnetite by oxygen-rich selective leaching.

Background technique

Vanadium is located in the 4th cycle of the periodic table, VB group, its atomic number is 23, atomic weight is 50.9415, which belongs to the high melting point element in the excessive metal element; vanadium has various oxides, and the industrial vanadium oxide is mainly V. ₂ O ₂ , V ₂ O ₃ , V ₂ O ₄ , especially in the form of V ₂ O ₅ , entered the 20th century, the first British production of vanadium-containing alloy steel, the first breakthrough in the application of vanadium; subsequently applied The battery industry, as one of the most promising new energy storage systems, while the important metal alloy Ti-6A1-4V composed of vanadium and titanium is widely used in military, aerospace, superconducting, nuclear reactor and other fields; the total of vanadium in the earth's crust The content is ranked 22nd in the metal. Although the content is quite small, it is very scattered. So far, no vanadium ore has been found. It is mainly symbiotic with some metal ores. China has abundant vanadium reserves, mainly vanadium-titanium magnetite and carbonaceous. Shale is used as a raw material for industrial production.

Titanium content accounts for about 0.61% of the crustal mass. It is ranked as the fourth structural metal after aluminum, iron and magnesium according to the abundance of elements in the earth's crust. Its chemical nature is active, and there is no elemental state in nature. Compounds such as acid salts are widely found in seawater, soil, rocks, animals and plants; although there are many minerals containing titanium, the main applications in the industry are ilmenite, vanadium-titanium magnetite and rutile ore; The most widely distributed titanium-containing minerals are ilmenite, accounting for about 80% of titanium ore resources. It is also the main raw material for the preparation of titanium products; currently more than 90% of the world's titanium ore is used to produce titanium dioxide. 4 to 5% of titanium ore is used to produce titanium metal, and the remaining ilmenite is used to make electrodes, alloys, carbides, ceramics, glass and chemicals. Titanium dioxide is chemically known as titanium dioxide and is a white inorganic pigment. It is non-toxic, harmless, optimal opacity, best whiteness and brightness. It is considered to be the best white pigment in the world. It is widely used in coatings, plastics, paper and printing. Ink, chemical fiber, rubber, cosmetics and other industries.

Vanadium-titanium magnetite is mainly composed of iron (Fe), vanadium (V) and titanium (Ti), accompanied by various valuable elements such as cobalt (Co), nickel (Ni), chromium (Cr), copper ( Multi-symbiotic iron ore of Cu), strontium (Sc), gallium (Ga), etc., due to the close symbiosis of Fe and Ti, V is present in the form of isomorphism in the titanomagnetite. magnetite. Vanadium-titanium magnetite is currently the main resource for the production of vanadium and titanium, and can recycle vanadium, iron and titanium. Vanadium-titanium magnetite deposits are widely distributed in China, with abundant reserves. The reserves and production volume ranks third in the national iron ore mines. The proven reserves are 6.19 billion tons, accounting for 11.6% of the country's proven iron reserves. Such deposits are mainly distributed in Xichang area of Panzhihua, Sichuan, Chengde area of Hebei, Fuyang, Hubei and Fuyang.

At present, the main methods for extracting vanadium from vanadium-titanium magnetite are mainly fire method and wet method. The fire method is to smelt vanadium-titanium magnetite in blast furnace or electric furnace to obtain vanadium-containing pig iron, and then selectively oxidize. The method further oxidizes vanadium in the molten iron into the slag, and further extracts vanadium from the obtained vanadium-containing slag; the wet method comprises pre-treating the vanadium-titanium magnetite, and the multivalent vanadium element in the vanadium-titanium magnetite is It is converted into a water-soluble salt of pentavalent vanadium with the aid of sodium salt, calcium salt or oxygen, and then the slag obtained by calcination is subjected to water immersion or acid leaching, and the water-soluble salt of vanadium and a part of impurity metal salt enter the leaching solution. In the process of purifying the leachate and adding the ammonium salt or the calcium salt precipitation method, the vanadium acid compound can be precipitated. In order to obtain a relatively pure product, the crude vanadium pentoxide needs to be subjected to alkali dissolution and impurity removal treatment, and ammonium is carried out. The second precipitation of vanadium salt can obtain the pure ammonium ammonium metavanadate, and the high purity vanadium pentoxide is obtained after calcination; the wet process has the characteristics of high total yield; the patent No. 201010188625.7 proposes the ore or concentrate. After being crushed, it is mixed with sodium salt, oxidized and calcined, and vanadium and chromium are converted into water-soluble sodium vanadate and sodium chromate. The water is immersed in the solution, and vanadium chromium is separated from the solution to obtain vanadium pentoxide and trioxide. Chromium product; residue after leaching can be blended into pulverized coal pelletizing, reduction, magnetic separation of iron and titanium, magnetic iron powder can be used as raw material for powder metallurgy or steelmaking, and non-magnetic products containing TiO ₂ greater than 50% The raw material for titanium extraction; the calcination process of the method consumes a large amount of energy, and the vanadium pentoxide, iron and titanium oxide prepared by the method contain more impurities, which are primary industrial raw materials, and the added value of the product is low; application number 201310183580.8 The patent mentions a method for preparing a titanium liquid by a wet treatment of a vanadium-titanium magnetite concentrate, mixing a vanadium-titanium magnetite concentrate with hydrochloric acid, leaching to obtain an intermediate slurry, and filtering the intermediate slurry to obtain a leachate and a leach residue, followed by washing with water. The washing water and the washing residue are filtered, and the washing residue is subjected to a molten salt reaction to obtain a molten salt reaction material; the molten salt reaction material is washed with water and filtered to obtain a water washing material; the water washing material is pickled to obtain a slurry, and the mixture is filtered to obtain pickling. Acid The washing material is acid-dissolved with sulfuric acid solution to obtain an acid-soluble material; the acid-dissolved material is added to the sulfuric acid solution for leaching, and the obtained leaching liquid is titanium liquid; the method ignores the vanadium-titanium magnetite Contains a large amount of iron-containing compounds, and a variety of high value-added metal elements, low resource utilization.

Summary of the invention

According to the research on the existing vanadium-titanium magnetite production process, the invention provides a method for extracting valuable components in vanadium-titanium magnetite by oxygen-rich selective leaching, using vanadium-titanium magnetite as raw material to oxidize Sodium and hydrochloric acid are used as solvents, and the vanadium-titanium magnetite is subjected to high-pressure oxygen-enriched alkali leaching and high-pressure acid leaching to prepare titanium dioxide by mechanical activation, oxygen enrichment and high pressure, and is prepared by subsequent purification and crystal transformation. High purity TiO _{2 is obtained} ; the vanadium element in the leachate is subjected to ammonium salt precipitation recovery and calcination to obtain high-purity vanadium oxide, thereby enriching vanadium elements, reducing energy consumption, and effectively reducing the acid-base concentration in the leaching process, and Recycling to achieve recycling of resources, while improving equipment working conditions and extending equipment life.

The method of the invention proceeds as follows:

1. The vanadium-titanium magnetite is crushed to a particle size of ≤0.125 mm to obtain a vanadium-titanium magnetite powder; the vanadium-titanium magnetite powder and the sodium hydroxide solution are placed in an autoclave for caustic soaking, wherein the sodium hydroxide solution The mass concentration is 20-40%, the ratio of sodium hydroxide solution to vanadium-titanium magnetite powder is (5-15):1; oxygen is introduced into the autoclave for alkali leaching, and then the temperature is raised to 200~ At 300 °C, the mixture is kept under stirring for 1 to 3 hours to complete the alkali leaching; 2. The alkali leached material is separated by filtration to obtain the alkali decomposition product and the alkali immersion liquid; the alkali decomposition product is washed with water until the filtrate is neutral, and the alkali is formed into a base. Decompose slag;

3. Adding ammonium salt to the alkali immersion liquid, the molar ratio of VO ₄ ³⁺ in the alkali immersion liquid to NH ₄ ⁺ in the ammonium salt is 1:3, standing still until the precipitate is completely precipitated, and the solid is separated by filtration. Phase and liquid phase; the solid phase is dried to remove moisture, and then calcined at 850 ± 5 ° C for 30 to 60 minutes to form vanadium oxide;

4, the alkali decomposition slag and hydrochloric acid in the acid leaching autoclave, wherein the concentration of hydrochloric acid is 14 to 20%, the ratio of hydrochloric acid to alkali decomposition slag according to liquid-solid ratio (4 ~ 10): 1; The seed crystal is added to the autoclave for acid leaching to facilitate the growth of the titanium oxide nucleation formed by the alkali decomposition slag during the hydrolysis of hydrochloric acid, and then the temperature is raised to 120-150 ° C, and the mixture is kept under stirring for 1 to 3 hours to complete the acid. Immersion hydrolysis

5. The acid leached and hydrolyzed material is separated by filtration to obtain a hydrolyzate and an acid leaching solution; the hydrolyzed product is washed with water until the filtrate is neutral, and then dried to remove water, and finally calcined at 800 to 900 ° C for 30 to 60 minutes to be oxidized. titanium.

In the above method, the liquid phase obtained in the step 3 is used to remove SiO ₂ by using CaO as a precipitating agent, and the calcium silicate by-product is recovered. When the weight percentage of SiO _{2 in the} liquid phase is ≤ 0.05%, it is returned to the step 1 as a sodium hydroxide solution.

The above seed crystal is titanium dioxide and/or metatitanic acid in an amount of 0.2 to 0.5% by weight based on the total weight of the alkali decomposition slag.

In the above method, after the obtained acid immersion liquid is heated and evaporated, the excess hydrogen chloride in the acid immersion liquid is volatilized, and the hydrochloric acid prepared by absorption is concentrated to a weight concentration of 14 to 20%, and is returned to the step 4.

The above vanadium oxide purity is ≥95%.

The above titanium oxide has a purity of ≥ 98.5% and a particle size of 0.1 to 13 μm.

The material remaining after the above-mentioned acid immersion liquid is heated and evaporated is separated into a single metal salt solution by extraction, and the metal salt solution is electrolyzed by an electrolytic cell to prepare a high-purity hydroxide precipitate; for example, Fe is used as a Fe ³⁺ ion concentration. Higher, in order to prevent iron hydroxide agglomeration, a small amount of iron red is added before iron removal, and the cathode area of the electrolytic cell is mechanically stirred, and the electrolyte and hydroxide in the cathode area are directed to flow, and then filtered by a filtering device to achieve solidification. The liquid is separated, and the filtrate is recycled to the cathode region to obtain ultrafine high-purity iron red. According to the same principle, the impurity metal ions are separately removed; since the metal salt solution contains impurities, the metal ions have their activities after H ⁺ , and the leaching solution is in the electrolysis process. Containing a large amount of Cl ^- , so there will be hydrogen and chlorine gas between the two stages of the electrolysis cell; collecting anode and cathode gases to obtain by-product hydrogen and chlorine; drying and filtering the electrolysis product to obtain impurity hydroxide products, or calcining the electrolysis products Metal oxide products.

The main reactions involved in the direct separation of the hydroxide precipitation by electroporation are as follows:

Anodic reaction: 2Cl ^- -2e = Cl ₂ ↑,

Cathodic reaction: 2H ⁺ +2e = H ₂ ↑,

Total reaction: MeCl ₂ +2H ₂ O=Me(OH) ₂ +H ₂ +Cl ₂ ,

Calcination reaction: Me(OH)=MeO+H ₂ O↑.

The principles and benefits of the present invention are:

(1) Oxygen is introduced during the leaching process to oxidize titanium, iron, and vanadium oxides in the vanadium-titanium magnetite, destroying the stable magnetite ore phase, and dispersing the impurity elements in the solid solution. Combining into a compound which can be fused to an acid and a base, is separated and removed in a subsequent washing and filtering stage;

(2) to ensure the tightness of the system during the leaching process, as the oxygen is introduced or the temperature continues to rise, a large gas pressure is generated in the kettle, and the kinetic conditions of the leaching process are greatly optimized. Iron ore oxidation, impurity precipitation, mineral phase destruction have a promoting effect, as a means of enhanced leaching in the process of interaction with other leaching process parameters, the temperature, pH, leaching time and other process conditions can be appropriately reduced, Reach environmental protection and energy conservation purposes;

(3) Alkali leaching of vanadium-titanium magnetite will have a certain destructive effect on the surface of the slag particles, which is conducive to the precipitation of impurity phases, enhance the effect of subsequent acid leaching, and simultaneously use acid-base distribution leaching, which is simpler than acid leaching. The impurity removal rate of oxides such as Si and Al is greatly increased, the dedusting pressure of the subsequent production process is greatly reduced, and high-performance materials are easily prepared, and the oxygen-rich acid leaching oxidizes Fe ²⁺ in the leachate. Will improve the efficiency of post-electrical transformation of iron sink process;

(4) The alkali used is sodium hydroxide. The waste alkali liquor produced during the alkali leaching process can be added with a small amount of ammonium salt, and the vanadate ion can be precipitated as a precipitate, filtered to obtain enrichment; then a small amount of CaO is added. The calcium silicate is formed to effectively remove the Si impurities, thereby achieving the purpose of enriching and removing vanadium oxide, and the lye after filtration can be further used for alkali leaching of vanadium-titanium magnetite to achieve resource recycling; acid leaching The process uses hydrochloric acid, the generated waste acid is heated, and the HCl gas volatilized by heating is absorbed by water atomization, and the formed hydrochloric acid solution is concentrated and returned to the leaching process to realize recycling of resources, and almost no industrial waste water or waste residue is realized to realize green. produce;

(5) The impurity ions can be separated and electrically converted by using the extraction principle, and the obtained metal oxide or hydroxide has high purity, and ultra-fine high-purity oxide can be obtained by drying and calcining, and electrolysis can be produced. The valuable by-product hydrogen and chlorine gas can be recycled back to the process through the impurity-free acidic leachate to achieve green recycling and energy saving.

Detailed ways:

In the embodiment of the present invention, CaO is used as a precipitating agent and a silicate ion in a lye is formed to form a calcium silicate precipitate for preparing cement.

The autoclave for caustic soak used in the embodiment of the present invention is a ZRYK 1L stainless steel nickel-plated autoclave of Weihai Zhengwei Machinery Equipment Co., Ltd.

The autoclave for acid leaching used in the examples of the present invention is a KCFD1-10 type zirconium autoclave of Yantai Keli Chemical Equipment Co., Ltd.

The titanium concentrate crushing device in the embodiment of the present invention is a pulverisette 5/4 classic line type planetary high energy ball mill of FRITSCH.

The liquid-solid ratio in the embodiment of the present invention is the weight ratio of the volume of the liquid material (sodium hydroxide solution or hydrochloric acid) to the solid material (vanadium-titanium magnetite powder or alkali-decomposed slag), and the unit is L/kg.

In the examples of the present invention, the stirring speed in the alkali immersion was 500 r/min, and the stirring speed in the acid leaching hydrolysis was 300 rpm.

The titanium dioxide and metatitanic acid used in the examples of the present invention are commercially available analytically pure reagents.

In the embodiment of the present invention, the material remaining after heating and evaporation of the acid immersion liquid is separated into a single metal salt solution by an extraction method, and the metal salt solution is electrolyzed by an electrolytic cell (temperature: 20 ° C, cell voltage: 20 V) to prepare a high-purity hydroxide precipitate; Taking Fe as an example, in order to prevent the iron hydroxide from agglomerating due to the high concentration of Fe ³⁺ ions, a small amount of iron red is added before the iron removal, and the cathode region of the electrolytic cell is mechanically stirred, and the electrolyte and hydroxide in the cathode region are directed to flow. At this time, filtration is performed by a filtering device to realize solid-liquid separation, and the filtrate is recycled to the cathode region to obtain ultrafine high-purity iron red; according to the same principle, the impurity metal ions are separately removed; since the metal salt solution contains impurity metal ions thereof After the activity is located at H ⁺ , the leaching solution contains a large amount of Cl ⁻ during the electrolysis process, so hydrogen and chlorine gas are formed between the two stages of the electrolysis cell; the anode and cathode gases are collected to obtain by-product hydrogen and chlorine gas; and the electrolysis product is dried to obtain impurity hydrogen. The oxygen product, or the metal oxide product obtained after calcination of the electrolytic product, has a purity of ≥95%.

The present invention will be further described in detail below with reference to the embodiments.

The vanadium titano-magnetite used in the specific embodiment of the present invention contains 12.8% by weight of TiO ₂ , 3.8 % of SiO ₂ , 1.1% of CaO, 3.22% of MgO, 53.7% of TFe, 0.24% of MnO, and 2.86% of Al ₂ O ₃ . , V ₂ O ₅ 0.53%.

Example 1

The vanadium-titanium magnetite is crushed to a particle size of ≤0.125 mm to obtain a vanadium-titanium magnetite powder; the vanadium-titanium magnetite powder and the sodium hydroxide solution are placed in an autoclave for caustic soaking, wherein the mass concentration of the sodium hydroxide solution 20%, the ratio of sodium hydroxide solution to vanadium-titanium magnetite powder is 5:1 according to liquid-solid ratio; oxygen is introduced into the autoclave for alkali leaching, then the temperature is raised to 200 ° C, and the mixture is kept under stirring for 3 hours. The alkali leaching is completed; the alkali leached material is separated by filtration to obtain an alkali decomposition product and an alkali immersion liquid; the alkali decomposition product is washed with water until the filtrate is neutral to be an alkali decomposition slag;

The ammonium salt is added to the alkali immersion liquid in an amount of 1:3 in a molar ratio of VO ₄ ³⁺ in the alkali immersion liquid to NH ₄ ⁺ in the ammonium salt, and is allowed to stand until the precipitate is completely precipitated, and the solid phase is obtained by filtration and separation. Liquid phase; the solid phase is dried to remove water, and then calcined at 850 ± 5 ° C for 30 min to prepare vanadium oxide, the purity is 96.5%; wherein the washing liquid formed after washing is collected, added to the alkali immersion liquid; CaO is used as a precipitating agent to remove SiO ₂ , and when the weight percentage of SiO _{2 in the} liquid phase is ≤0.05%, it is recycled as a sodium hydroxide solution;

The alkali decomposition slag and hydrochloric acid are placed in an autoclave for acid leaching, wherein the weight concentration of hydrochloric acid is 14%, the ratio of hydrochloric acid to alkali decomposition slag is 10:1, and the liquid-solid ratio is added to the autoclave for acid leaching. Seed crystal, easy to alkali decomposition slag in the process of hydrochloric acid hydrolysis of titanium oxide nucleation growth, heating to 120 ° C, holding under stirring for 3h, complete acid leaching hydrolysis; seed crystal is titanium dioxide, seed crystal addition 0.5% of the total weight of the alkali decomposition slag;

The acid leached and hydrolyzed material is separated by filtration to obtain a hydrolyzate and an acid immersion liquid; the hydrolyzed product is washed with water until the filtrate is neutral, and then dried to remove water, and finally calcined at 900 ° C for 30 min to prepare titanium oxide; the acid immersion liquid is heated After evaporation, the evaporated hydrogen chloride gas is atomized and absorbed by water, and the prepared hydrochloric acid is concentrated to a mass concentration of 14% and recycled; the purity of the titanium oxide is 98.5%, and the mass percentage includes SiO ₂ 0.31%, CaO 0.07%, MgO. 0.96%, TFe 3.6%, Mn 0.18%; particle size 0.16 to 4.29 microns.

Example 2

The method is the same as that in Embodiment 1, except that:

(1) The weight concentration of sodium hydroxide solution is 30%, the ratio of sodium hydroxide solution to vanadium-titanium magnetite powder is 10:1 according to liquid-solid ratio; the alkali immersion temperature is 250 °C, time 2h; (2) solid phase After drying, it is calcined for 40 minutes to prepare vanadium oxide with a purity of 97.2%;

(3) The concentration of hydrochloric acid is 18%, the ratio of hydrochloric acid to alkali decomposition slag is 8:1; the temperature of alkali leaching is 130 °C, time 2h; the seed crystal is metatitanic acid, the amount is alkali Decompose 0.3% of the total weight of the slag;

(4) After washing and drying the hydrolyzed product, it is calcined at 850 ° C for 40 min; hydrochloric acid obtained by absorption of hydrogen chloride gas is concentrated to a weight concentration of 18%; the purity of titanium oxide is 98.7%, and SiO _{2 is} 0.22% by mass, CaO 0.07 %, MgO 0.64%, TFe 2.1%, Mn 0.16%; particle size of 0.5 to 12 microns.

Example 3

The method is the same as that in Embodiment 1, except that:

(1) The mass concentration of sodium hydroxide solution is 40%, the ratio of sodium hydroxide solution to vanadium-titanium magnetite powder is 15:1 according to liquid-solid ratio; the alkali immersion temperature is 300 °C, time 1h; (2) solid phase After drying, it is calcined for 60 minutes to prepare vanadium oxide with a purity of 96.7%;

(3) The mass concentration of hydrochloric acid is 20%, the ratio of hydrochloric acid to alkali decomposition slag is 4:1; the temperature of alkali leaching is 150 ° C, time 1 h; the seed crystal is the quality of titanium dioxide and metatitanic acid. The mixture is added in an amount of 0.2% by weight based on the total weight of the alkali decomposition slag;

(4) After the water-washed product is washed and dried, it is calcined at 800 ° C for 60 min; the hydrochloric acid obtained by hydrogen chloride gas absorption is concentrated to a mass concentration of 20%, and recycled; the purity of the titanium oxide is 98.9%, and the content of SiO _{2 is} 0.18% by mass. CaO 0.07%, MgO 0.32%, TFe 1.5%, Mn <0.05%; particle size 0.8-1 microns.

Claims (6)

1. A method for extracting valuable components in vanadium-titanium magnetite by oxygen-rich selective leaching, which is characterized by the following steps:

   (1) crushing vanadium-titanium magnetite to a particle size of ≤0.125 mm to obtain vanadium-titanium magnetite powder; placing vanadium-titanium magnetite powder and sodium hydroxide solution in an autoclave for caustic soaking, wherein sodium hydroxide solution The mass concentration is 20-40%, the ratio of sodium hydroxide solution to vanadium-titanium magnetite powder is (5-15):1; oxygen is introduced into the autoclave for alkali leaching, and then the temperature is raised to 200. ~300 ° C, under stirring conditions for 1 ~ 3h, complete alkali leaching; (2) the alkali leached material is filtered and separated to obtain alkali decomposition products and alkali immersion liquid; the alkali decomposition product is washed to the filtrate to be neutral, Alkali decomposition slag;

   (3) adding an ammonium salt to the alkali immersion liquid in an amount of 1:3 in a molar ratio of VO ₄ ³⁺ in the alkali immersion liquid to NH ₄ ⁺ in the ammonium salt, standing still until the precipitate is completely precipitated, and obtained by filtration. Solid phase and liquid phase; solid phase drying to remove water, and then calcined at 850 ± 5 ° C for 30 ~ 60min, to make vanadium oxide;

   (4) The alkali decomposition slag and hydrochloric acid are placed in an autoclave for acid leaching, wherein the mass concentration of hydrochloric acid is 14 to 20%, and the ratio of hydrochloric acid to alkali decomposition slag is liquid to solid ratio (4 to 10): 1 Adding seed crystals to the acid leaching autoclave to facilitate the growth of the titanium oxide nucleation formed by the alkali decomposition slag during the hydrolysis of hydrochloric acid, raising the temperature to 120-150 ° C, and incubating for 1 to 3 hours under stirring to complete the acid Immersion hydrolysis

   (5) filtering and separating the material after acid leaching to obtain a hydrolyzate and an acid leaching solution; washing the hydrolyzed product until the filtrate is neutral, drying and removing the water, and finally calcining at 800-900 ° C for 30-60 min, Titanium oxide.
2. The method for extracting valuable components in vanadium titano-magnetite by oxygen-rich selective leaching according to claim 1, characterized in that the liquid phase obtained in the step (3) uses CaO as a precipitating agent to remove SiO ₂ and recover silicon. Calcium acid by-product; when the mass percentage of SiO _{2 in the} liquid phase is ≤ 0.05%, it is returned to the step (1) as a sodium hydroxide solution.
3. The method for extracting valuable components in vanadium titano-magnetite by oxygen-rich selective leaching according to claim 1, wherein the seed crystal is titanium dioxide and/or metatitanic acid, and the amount of alkali decomposition is 0.2 to 0.5% of the total weight of the slag.
4. The method for extracting valuable components in vanadium titano-magnetite by oxygen-rich selective leaching according to claim 1, characterized in that the acid immersion liquid obtained in the step (5) is heated and evaporated, and the excess hydrogen chloride is volatilized out of water. The hydrochloric acid prepared by atomization absorption is concentrated to a weight concentration of 14 to 20%, and is returned to the step 4.
5. The method of claim 1, wherein the vanadium oxide has a purity of ≥95%.
6. The method of claim 1, wherein the titanium oxide has a purity of ≥ 98.5% and a particle size of 0.1 to 13 microns.