A process for the co-production of synthetic rutile and iron oxide pigments from reduced ilmenite

Abstract

The application discloses a method for co-production of artificial rutile and iron oxide pigment by reducing ilmenite, and relates to the technical field of ilmenite processing, which comprises the following steps: mixing the reduced ilmenite containing 30%-40% of metallic iron with a rusting agent to obtain a rusting system, adding a crystal form promoter and / or a crystal nucleus suspension into the rusting system, passing in air, adjusting the pH value of the system to 2.0-6.0, controlling the reaction temperature at 70-95 DEG C, and performing a rusting reaction to obtain a mixture comprising coarse-grained solid and fine-grained suspension; separating the coarse-grained solid from the fine-grained suspension in the mixture, and respectively performing post-treatment to obtain the artificial rutile and the iron oxide pigment; the rusting agent comprises 0.3%-1% of hydrochloric acid, and the solid-liquid mass ratio of the reduced ilmenite to the rusting agent is 1:1-3. The method realizes the co-production of the artificial rutile and the iron oxide pigment, avoids the reprocessing of the by-product iron oxide mud, simplifies the technological process, and significantly reduces the energy consumption and production cost.

Description

Technical Field

[0001] This application relates to the field of ilmenite processing technology, and in particular to a method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite. Background Technology

[0002] Reduction etching is one of the important methods for producing synthetic rutile. This method uses an etching reaction to convert metallic iron in reduced ilmenite into suspended iron oxide, which is then removed, resulting in synthetic rutile with a high titanium dioxide content. However, this process generates a large amount of suspended iron oxide, which typically forms iron oxide sludge after pressure filtration. Currently, iron oxide sludge is a byproduct with low economic value, and improper disposal may have environmental impacts. To enhance the value of this byproduct, existing technologies attempt to further process iron oxide sludge into iron oxide pigments. However, this process has significant drawbacks: First, the quality of the iron oxide sludge depends on the initial etching process, and the instability of the etching process itself can easily lead to poor performance in terms of particle size, crystal form, color uniformity, and coloring rate in the final iron oxide pigment; second, the secondary processing from iron oxide sludge to iron oxide pigments usually involves complex post-processing steps, resulting in high energy consumption and increased production costs. Therefore, how to obtain high-quality iron oxide pigments directly from the corrosion process and achieve the simultaneous and efficient co-production of artificial rutile and high-quality iron oxide pigments has become a technical problem that urgently needs to be solved. Summary of the Invention

[0003] The main purpose of this application is to propose a method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite, aiming to solve the technical problems in the existing technology of low added value of iron oxide by-product in the production process of synthetic rutile, complex subsequent processing of iron oxide pigments, unstable quality and high energy consumption.

[0004] To achieve the above objectives, in a first aspect, this application proposes a method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite, comprising the following steps: A rusting system is obtained by mixing reduced ilmenite containing 30% to 40% metallic iron with a rusting agent. A crystal form promoter and / or crystal nucleus suspension are added to the rusting system, air is introduced, the pH value of the system is adjusted to 2.0 to 6.0, the reaction temperature is controlled at 70 to 95°C, and the rusting reaction is carried out to obtain a mixture including coarse solid particles and fine suspension particles. The coarse solid particles and fine suspension in the mixture are separated and post-processed to obtain artificial rutile and iron oxide pigments, respectively. The rust-causing agent includes hydrochloric acid with a concentration of 0.3% to 1%, and the solid-liquid mass ratio of the reduced ilmenite to the rust-causing agent is 1:1 to 3.

[0005] In some embodiments, the amount of the crystal form promoter added is 5‰ to 2% of the amount of iron oxide pigment obtained; The amount of the crystal nucleus suspension added is 10% to 25% of the amount of iron oxide pigment obtained.

[0006] In some embodiments, the crystal form promoter is selected from one or more of phosphates, silicates, nitrates, oxalates, polyethylene glycol, manganese dioxide, aluminum salts, sodium dodecylbenzenesulfonate, and EDTA. In some embodiments, the crystal nucleus suspension is prepared by dissolving ferrous salt in water, adding alkali solution, mixing and reacting until gelation occurs.

[0007] In some embodiments, the reduced ilmenite has a particle size of 40 μm to 300 μm.

[0008] In some embodiments, the color of the iron oxide pigment is controlled by adjusting the pH value of the rusting reaction: when the pH is controlled at 4 to 4.5, iron oxide red pigment is obtained; when the pH is controlled at less than 4, iron oxide yellow pigment is obtained; and when the pH is controlled at 6, iron oxide black pigment is obtained.

[0009] In some embodiments, the separation of the coarse solid particles from the fine particle suspension is performed using a hydrocyclone and / or a high-frequency vibrating screen.

[0010] In some embodiments, the waste liquid after the rusting reaction is recycled in the method as a rusting agent or as feed water.

[0011] Secondly, this application also proposes a synthetic rutile, which is prepared using the method proposed in the first aspect of this application, which utilizes the reduction of ilmenite to co-produce synthetic rutile and iron oxide pigment.

[0012] Thirdly, this application also proposes an iron oxide pigment, which is prepared by the method proposed in the first aspect of this application, which utilizes the reduction of ilmenite to co-produce artificial rutile and iron oxide pigment.

[0013] This application proposes a method for the co-production of synthetic rutile and iron oxide pigments using reduced ilmenite. This method involves simultaneously adding a crystal form promoter and / or a nucleation suspension to a rusting system composed of reduced ilmenite and hydrochloric acid etchant. The reaction is carried out under specific pH (2.0–6.0), temperature (70–95°C), and air circulation conditions. This directly transforms the traditional process of removing iron from metallic iron through rusting into a controllable process of iron oxide pigment crystal growth. The addition of the crystal form promoter and nucleation suspension effectively induces and regulates the nucleation and growth of iron oxide crystals. The iron oxide generated in the reaction system is no longer amorphous hydrated iron oxide or an unstable precursor, but directly forms iron oxide pigment particles with the desired crystal form, particle size, and color. These pigment particles exist as a fine-particle suspension, while the titanium component is enriched to form coarse-particle solids.

[0014] This method fundamentally solves the problem in the background technology where unstable rusting processes lead to poor quality byproducts that cannot be directly used as pigments. It achieves the simultaneous and direct generation of two main products—artificial rutile and iron oxide pigments—within the same reaction system. It avoids the reprocessing of the byproduct iron oxide sludge, simplifies the process, and significantly reduces energy consumption and production costs. Furthermore, by precisely controlling the pH value, it can flexibly produce iron oxide pigments of different colors (such as red, yellow, and black), with excellent coloring rates and other properties. The waste liquid after the rusting reaction can be recycled, achieving complete wastewater reuse and making it environmentally friendly. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 A process flow diagram of the method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite provided in this application; Figure 2 XRD pattern of the product obtained in Comparative Example 1 provided for this application; Figure 3 The XRD pattern of the product obtained in Comparative Example 2 provided for this application.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0020] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0021] Please see Figure 1 In a first aspect, embodiments of this application propose a method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite, comprising the following steps: S1. A rusting system is obtained by mixing reduced ilmenite containing 30% to 40% metallic iron with a rusting agent. A crystal form promoter and / or crystal nucleus suspension are added to the rusting system. Air is introduced to adjust the pH value of the system to 2.0 to 6.0. The reaction temperature is controlled at 70 to 95°C to carry out the rusting reaction and obtain a mixture including coarse solid particles and fine suspension particles. S2. Separate the coarse solid particles and fine suspension in the mixture, and obtain artificial rutile and iron oxide pigments through post-processing.

[0022] The rust-causing agent includes hydrochloric acid at a concentration of 0.3% to 1%, and the solid-liquid mass ratio of reduced ilmenite to the rust-causing agent is 1:1 to 3. For example, the concentration of hydrochloric acid in the rust-causing agent can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, etc. The solid-liquid mass ratio of reduced ilmenite to the rust-causing agent is 1:1, 1:2, or 1:3, etc.

[0023] The method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite proposed in this application builds upon the traditional reduction etching process for synthetic rutile. By introducing a crystal form promoter and / or a nucleation suspension into the etching system and precisely controlling the pH, temperature, and oxidation conditions of the reaction system, the side reaction that would otherwise produce amorphous hydrated iron oxide or low-quality iron oxide sludge is directly transformed into a controllable process for synthesizing iron oxide pigment crystals. This method uses hydrochloric acid as an etching agent to dissolve and reduce the metallic iron in ilmenite. The resulting ferrous ions, under the influence of an oxidizing environment with air and regulated by the crystal form promoter and / or induced by the nucleation suspension, directly generate iron oxide particles with specific crystal forms, colors, and excellent pigment properties in the reaction solution. Simultaneously, the titanium component is enriched in the form of titanium dioxide, forming coarse-grained solid particles. Through a single etching reaction, both the synthetic rutile precursor (coarse-grained solid particles) and the iron oxide pigment precursor (fine-grained suspension), which can be used as the main products, can be obtained simultaneously, achieving efficient and high-value comprehensive utilization of resources.

[0024] It should be noted that iron oxide black can be produced without the addition of a nucleation suspension and a crystal form promoter. Iron oxide red and iron oxide yellow, however, require the addition of seed crystals (nucleation suspension and crystal form promoter) because they are difficult to nucleate, brittle, and have unstable colors. Iron oxide black does not require external seed crystals because it rapidly and uniformly nucleates itself under corrosive conditions and has a high tolerance for grain size / hue. However, adding a nucleation promoter can help improve the black phase of iron oxide.

[0025] In some embodiments, the amount of crystal form promoter added is 5‰ to 2% of the amount of iron oxide pigment obtained. For example, the amount of crystal form promoter added is 5‰, 10‰, 50‰, 1% or 2% of the amount of iron oxide pigment obtained. The amount of crystal nucleation suspension added is 10% to 25% of the amount of iron oxide pigment obtained. For example, the amount of crystal nucleation suspension added is 10%, 15%, 20% or 25% of the amount of iron oxide pigment obtained.

[0026] Adding an appropriate amount of crystal form promoter can effectively regulate the growth habit of iron oxide crystals and prevent the formation of amorphous or impurity phases. Simultaneously, adding a predetermined amount of crystal nucleus suspension can provide sufficient and stable growth nuclei for the reaction system, allowing newly generated iron oxide to grow epitaxially based on these nuclei, thereby obtaining pigment particles with narrower particle size distribution and more regular morphology. If the addition amount is too low, the regulation and induction effects will be insignificant; if the addition amount is too high, it may lead to increased costs or the introduction of excessive impurities.

[0027] In some embodiments, the crystal form promoter is selected from one or more of phosphates, silicates, nitrates, oxalates, polyethylene glycol, manganese dioxide, aluminum salts, sodium dodecylbenzenesulfonate, and EDTA. In practical applications, a suitable crystal form promoter or combination thereof can be selected according to the type of the target iron oxide pigment (red, yellow, black).

[0028] In some embodiments, the crystal nucleus suspension is prepared by dissolving a ferrous salt in water, adding an alkaline solution, mixing, and reacting until gelation occurs. The ferrous salt can be ferrous sulfate (FeSO4·7H2O), ferrous chloride (FeCl2), etc. The alkaline solution can be sodium hydroxide, potassium hydroxide, or an ammonia solution. After mixing, under conditions of room temperature or slightly above room temperature, the ferrous ions are partially oxidized and hydrolyzed by introducing low-speed air or natural oxidation, gradually forming a precursor colloid of hydrated iron oxide or a specific crystal form of iron oxide. When the system "gels," that is, the viscosity increases significantly and it presents a brownish-yellow or reddish-brown gel-like appearance, it indicates that a large number of nano- or submicron-sized crystal nuclei have been formed.

[0029] In some embodiments, the particle size of the reduced ilmenite is 40 μm to 300 μm. For example, the particle size of the reduced ilmenite is 40 μm, 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, or 300 μm. Controlling the particle size of the raw material within this range is beneficial for the uniformity of the corrosion reaction and subsequent solid-liquid separation. Too small a particle size (<40 μm) may lead to an overly vigorous reaction, excessively high system viscosity, and too many fine particles are detrimental to the separation of synthetic rutile and iron oxide pigment suspension; too large a particle size (>300 μm) will result in incomplete corrosion, high residual metallic iron, and affect the grade of synthetic rutile and the yield of iron oxide pigment.

[0030] In some embodiments, the color of the iron oxide pigment is controlled by adjusting the pH value of the rusting reaction: when the pH is controlled at 4 to 4.5, iron oxide red pigment is obtained; when the pH is controlled at less than 4, iron oxide yellow pigment is obtained; and when the pH is controlled at 6, iron oxide black pigment is obtained.

[0031] pH is a key factor controlling the transformation pathway and final product of iron oxide hydrate. Under weakly acidic conditions (pH 4-4.5) and with air oxidation, ferrous ions are oxidized to ferric ions and tend to directly dehydrate and crystallize to form hematite (α-Fe₂O₃), i.e., iron oxide red. Under stronger acidic conditions (pH < 4), the tendency for ferric ions to hydrolyze and form goethite (α-FeOOH) increases, resulting in iron oxide yellow. When the pH of the system is controlled at around 6, a mixed oxide of ferrous and ferric ions may be generated simultaneously during the reaction, ultimately forming magnetite (Fe₃O₄) or a stable black iron oxide under these conditions, yielding iron oxide black. Through the above technical solution, the embodiments of this application achieve the goal of flexibly producing iron oxide pigments of different colors by simply adjusting the pH parameter in the same process unit.

[0032] In some embodiments, the separation of coarse solid particles from fine particle suspensions is achieved using hydrocyclones and / or high-frequency vibrating screens. Since the titanium-rich solids (synthetic rutile precursors) are coarser after the corrosion reaction, while the iron oxide pigment particles are finer, separation based on particle size difference is highly efficient and feasible. Hydrocyclones utilize centrifugal force to separate coarse and fine particles, while high-frequency vibrating screens achieve separation through mechanical sieving. Both can be used individually or in series for better separation results.

[0033] In some embodiments, the waste liquid after the rusting reaction is recycled in the method as a rusting agent or as feed water. After the rusting reaction is completed and the solid products are separated, the remaining liquid phase still contains unconsumed acid, soluble iron salts, and other ions. Recycling this waste liquid as a diluent for the rusting agent in the next batch of reaction, or as feed water for preparing crystal nucleation suspensions and adjusting pH, can minimize the consumption of fresh water and acid, achieving near-zero wastewater discharge. This not only reduces production costs but also completely solves the environmental problems of high difficulty and cost in treating acidic iron-containing wastewater in traditional processes.

[0034] In some implementations, post-processing includes filtration, drying, etc.

[0035] This application also proposes an artificial rutile prepared by the above method. This artificial rutile is derived directly from coarse-grained solid particles after a corrosion reaction. After washing and drying, its TiO2 content is significantly increased, for example, reaching over 86%, which meets the product standards for artificial rutile.

[0036] This application also proposes an iron oxide pigment prepared by the above method. This iron oxide pigment is derived directly from fine particles in the suspension after the rust reaction. After solid-liquid separation, washing, drying, and pulverization, its color, tinting strength, particle size, and other indicators all meet the requirements of commercial iron oxide pigments, such as the iron oxide red, yellow, and black pigments shown in the embodiments.

[0037] The following specific examples provide further details.

[0038] In the following examples and comparative examples, the reduced ilmenite was obtained from the ilmenite reduction process, and its main components (mass percentage) included: titanium dioxide TiO2 60.67%, total iron TFe 34.9% (metallic iron Mfe 31.29%).

[0039] Example 1 Crystal nucleus suspension A was prepared at room temperature by dissolving 162g of 7H2O·FeSO4 in 2.7L of water and 49g of sodium hydroxide in 0.28L of water. The mixture was stirred and air was bubbled in at a low speed, and the reaction was allowed to proceed for 1 hour until it became gelatinous and brown. 200g of reduced ilmenite was taken and 600g of 0.3% hydrochloric acid was added. Then, 0.7L of nucleus suspension A, 50g of ferrous salt, 0.2g of sodium oxalate, and 0.3g of aluminum sulfate were added sequentially. Air was bubbled in at a flow rate of 1L / min, and the pH of the solution was adjusted to 4.5. The corrosion reaction temperature was maintained at 95℃, resulting in a mixture consisting of coarse solid particles and a fine suspension.

[0040] The coarse solid particles and fine suspension in the mixture after the corrosion reaction were separated by a hydrocyclone and then filtered and dried to obtain artificial rutile and iron oxide red pigments.

[0041] Testing revealed that the TiO2 content in the synthetic rutile was 87.38%, and the resulting iron oxide red pigment had a hue close to 180 / 190.

[0042] Example 2 Nucleus suspension A was prepared at room temperature by dissolving 162g of 7H2O·FeSO4 in 2.7L of water and 49g of sodium hydroxide in 0.28L of water. The mixture was stirred and air was bubbled in at a low speed, and the reaction was allowed to proceed for 1 hour until it began to gel and turn brown. 200g of reduced ilmenite was then added to 600g of 0.3% hydrochloric acid, followed by 0.7L of nucleus suspension A, 50g of ferrous salt, 0.1g of aluminum sulfate, and 0.4g of manganese dioxide. Air was bubbled in at a flow rate of 1L / min, and the pH of the solution was adjusted to 4. The corrosion reaction was carried out at 95℃, resulting in a mixture consisting of coarse solid particles and a fine suspension.

[0043] The coarse solid particles and fine suspension in the mixture after the corrosion reaction were separated by a hydrocyclone and then filtered and dried to obtain artificial rutile and iron oxide red pigments.

[0044] Testing revealed that the TiO2 content in the synthetic rutile was 88.02%, and the resulting pigment was iron oxide red with a color close to 190.

[0045] Example 3 Crystal nucleation suspension B was prepared at room temperature by dissolving 5g of FeCl22O3 in 3.2L of water and 50g of sodium hydroxide in 0.33L of water. The mixture was then bubbled with low-speed air and reacted for 3 hours until it gelled and turned yellow. 200g of reduced ilmenite was then added to 0.7L of the above crystal nucleation suspension B, 0.1g of sodium oxalate, 0.2g of aluminum sulfate, 0.2g of manganese dioxide, and 600g of 0.8% hydrochloric acid. Air was bubbled in at a flow rate of 1L / min, the pH of the system was controlled at 3, and the temperature of the rusting system was maintained at 70℃, resulting in a mixture comprising coarse solid particles and a fine suspension.

[0046] The coarse solid particles and fine suspension in the mixture after the rust reaction were separated by a high-frequency vibrating screen, and then filtered and dried to obtain artificial rutile and iron oxide yellow pigments.

[0047] Testing revealed that the TiO2 content in the synthetic rutile was 87.06%, and the resulting iron oxide yellow pigment achieved a coloring rate of 91.66%, which is far superior to that of natural iron oxide yellow 316.

[0048] Example 4 Take 200g of reduced ilmenite, add 600g of rust-etching solution, adjust the pH of the rust-etching solution to 6, add 0.5g of sodium tripolyphosphate, adjust the air flow rate to 1L / min, and control the temperature of the rust-etching system at 70~80℃ until the rust-etching system turns black.

[0049] First, a hydrocyclone and then a high-frequency vibrating screen are used to separate the coarse solid particles and fine suspension in the mixture after the rust reaction. The mixture is then filtered and dried to obtain artificial rutile and iron oxide black pigments.

[0050] Testing revealed that the synthetic rutile TiO2 content was 86.79%, and the resulting iron oxide black pigment achieved a coloring rate of 116% compared to 330 and 125% compared to natural iron oxide black 710.

[0051] Example 5 Take 200g of reduced ilmenite, add 600g of rust-etching solution, adjust the pH of the rust-etching solution to 6, adjust the air flow rate to 1L / min, and control the temperature of the rust-etching system at 70~80℃ until the rust-etching system turns black.

[0052] First, a hydrocyclone and then a high-frequency vibrating screen are used to separate the coarse solid particles and fine suspension in the mixture after the rust reaction. The mixture is then filtered and dried to obtain artificial rutile and iron oxide black pigments.

[0053] Testing revealed that the synthetic rutile TiO2 content was 87.21%, and the resulting iron oxide black pigment achieved a coloring rate of 115.4% compared to 330, and 123.8% compared to natural iron oxide black 710.

[0054] Comparative Example 1 Take 200g of reduced ilmenite, add 600g of 0.3% hydrochloric acid, introduce air at a flow rate of 1L / min, adjust the pH of the solution system to 4.5, and set the corrosion reaction temperature at 95℃ to obtain a mixture.

[0055] The obtained mixture was subjected to X-ray diffraction analysis, and the results are as follows: Figure 2 As shown. From Figure 2 It can be seen that the mixture contains hydrated iron oxide, and the color does not conform to iron oxide red. Comparative Example 2 Take 200g of reduced ilmenite, add 600g of 0.3% hydrochloric acid, add catalyst (acetic acid + AEO), introduce air at a flow rate of 1L / min, adjust the pH of the solution system to 4.5, and set the corrosion reaction temperature at 95℃ to obtain a mixture.

[0056] The obtained mixture was subjected to X-ray diffraction analysis, and the results are as follows: Figure 3 As shown. From Figure 3 It can be seen that the mixture includes hydrated iron oxide.

[0057] As can be seen from Examples 1-5 and Comparative Examples 1-2, when a crystal form promoter and / or a nucleation suspension are added to the corrosion system and the pH is controlled within a specific range, not only can titanium be effectively enriched to obtain high-grade synthetic rutile, but high-performance iron oxide pigments (red, yellow, and black) can also be obtained simultaneously and directly. This is because the introduction of the crystal form promoter and the nucleation suspension effectively regulates the precipitation and crystallization path of iron oxides, allowing it to skip the intermediate stage of forming amorphous hydrated iron oxide and directly form iron oxide particles with stable crystal forms and pigment properties. In contrast, the comparative examples lacked these regulatory mechanisms, resulting only in a normal corrosion reaction, and the product was an amorphous substance unusable as a pigment. This demonstrates the key role and significant advantages of the proposed method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite in achieving the co-production of synthetic rutile and high-quality iron oxide pigments.

[0058] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for co-producing synthetic rutile and iron oxide pigments using reduced ilmenite, characterized in that, Includes the following steps: A rusting system is obtained by mixing reduced ilmenite containing 30% to 40% metallic iron with a rusting agent. A crystal form promoter and / or crystal nucleus suspension are added to the rusting system, air is introduced, the pH value of the system is adjusted to 2.0 to 6.0, the reaction temperature is controlled at 70 to 95°C, and the rusting reaction is carried out to obtain a mixture including coarse solid particles and fine suspension particles. The coarse solid particles and fine suspension in the mixture are separated and post-processed to obtain artificial rutile and iron oxide pigments, respectively. The rust-causing agent includes hydrochloric acid with a concentration of 0.3% to 1%, and the solid-liquid mass ratio of the reduced ilmenite to the rust-causing agent is 1:1 to 3.

2. The method as described in claim 1, characterized in that, The amount of the crystal form promoter added is 5‰~2% of the amount of iron oxide pigment obtained; The amount of the crystal nucleus suspension added is 10% to 25% of the amount of iron oxide pigment obtained.

3. The method as described in claim 1, characterized in that, The crystal form promoter is selected from one or more of phosphates, silicates, nitrates, oxalates, polyethylene glycol, manganese dioxide, aluminum salts, sodium dodecylbenzenesulfonate, and EDTA.

4. The method as described in claim 1, characterized in that, The crystal nucleus suspension is prepared by the following method: ferrous salt is dissolved in water, alkali solution is added, and the mixture is reacted until gelation occurs.

5. The method as described in claim 1, characterized in that, The reduced ilmenite has a particle size of 40μm to 300μm.

6. The method as described in claim 1, characterized in that, The color of the iron oxide pigment is controlled by adjusting the pH value of the rusting reaction: when the pH is controlled at 4~4.5, iron oxide red pigment is obtained; when the pH is controlled at less than 4, iron oxide yellow pigment is obtained; and when the pH is controlled at 6, iron oxide black pigment is obtained.

7. The method as described in claim 1, characterized in that, The separation of the coarse solid particles from the fine particle suspension is performed using a hydrocyclone and / or a high-frequency vibrating screen.

8. The method as described in claim 1, characterized in that, The waste liquid after the rusting reaction is recycled in the method as a rusting agent or as water for mixing ingredients.

9. A synthetic rutile, characterized in that, It is prepared by the method described in any one of claims 1 to 8, which utilizes reduced ilmenite to co-produce artificial rutile and iron oxide pigments.

10. An iron oxide pigment, characterized in that, It is prepared by the method described in any one of claims 1 to 8, which utilizes reduced ilmenite to co-produce artificial rutile and iron oxide pigments.

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