KR20210066329A - Method for selectively preparing iron oxide from mixed metal chlorides including iron - Google Patents

Abstract

The present application relates to a method for selectively preparing iron oxide from mixed metal chlorides including iron, and specifically, to a method for selectively preparing iron oxide, which comprises: a step for adding carbonate and/or a base as a precipitation additive to an aqueous iron-containing mixed metal chloride solution; and performing a hydrothermal reaction to obtain iron oxide.

Description

Method for the selective production of iron oxide from iron-containing mixed metal chlorides {METHOD FOR SELECTIVELY PREPARING IRON OXIDE FROM MIXED METAL CHLORIDES INCLUDING IRON}

The present application relates to a method for selectively producing iron oxide from iron-containing mixed metal chlorides. Specifically, it relates to a selective method for producing iron oxide, comprising adding a carbonate and/or a base as a precipitation additive to an aqueous iron-containing mixed metal chloride solution and performing a hydrothermal reaction to obtain iron oxide.

Mixed metal chloride aqueous solution with high iron content produced incidentally in industrial processes can be roughly divided into two types. One is a mixed metal chloride separated as cyclone dust in the process of producing _{TiCl 4} through a chlorination process using _{ilmenite, FeTiO 3} , which is a main component of iron and titanium, and the other is , is a high concentration of iron chloride contained in the wastewater solution generated from the pickling process of steel using hydrochloric acid as a cleaning agent. Since the concentration of metal ions other than iron is low in the solution discharged from the latter pickling process, it is converted into low-purity iron oxide and chlorine gas through a conventional roasting or fluidized roasting process. However, in the case of the mixed metal chloride produced in the ilmenite chlorination process, in addition to iron, manganese (Mn), aluminum (Al), magnesium (Mg), chromium (Cr), calcium (Ca), vanadium (V) Since impurities such as , niobium (Nb), and cobalt (Co) are contained in a weight ratio of up to 10%, iron cannot be utilized through a direct conversion method like the pickling process. Therefore, it is very important to separate only the iron component contained in the cyclone dust and convert it into a useful high-purity material. In addition, since the by-product contained in cyclone dust has a high acidity of pH 4 or less, it is not economical to treat these mixed metal chlorides directly as waste without a regeneration process because the cost burden is very high.

In this context, there is a need for developing a process for converting iron contained in the chlorination process by-product into a product such as iron oxide or iron chloride that can be utilized for commercial use.

US Patent No. 5,407,650 discloses a method of dissolving cyclone dust in dilute hydrochloric acid, _{using CaCO 3} as a neutralizing agent, selectively precipitating impurities contained in cyclone dust, separating and discarding as a solid, and obtaining a relatively pure remaining iron chloride solution. has been Here, the neutralizing agent was administered to the solution over the first and second rounds, and was carried out at a reaction temperature of 70°C. The method can be used to purify the iron chloride solution, but _{even if an excess of CaCO 3} is added as a neutralizing agent, the concentration of residual manganese in the solution is high, and above all, the amount of calcium increases by about 30 times.

US Patent No. 7,144,455 discloses a method for preparing α-FeOOH powder having high chromaticity from _{divalent FeCl 2} or FeSO ₄ by first making an α-FeOOH seed crystal and using it as a nuclide capable of growing the crystal. This is disclosed. In the above process, CaCO ₃ was used as a precipitating agent, and air was used as an oxidizing agent. The above process has the disadvantage that the amount of residual calcium in the product α-FeOOH powder is high, the reaction must proceed at 60° C. or higher, and above all, a mother crystal is required. However, it has the advantage of being able to manufacture α-FeOOH having a relatively high color coordinate.

US Patent No. 4,867,795 discloses a method for obtaining iron oxide containing a small amount of manganese and aluminum through a hydrothermal synthesis method using a precursor containing _{FeSO 4} as a main component and Al(OH) ₃ , KMnO ₄ , and NaAlO _{2 .} has been Although the iron oxide produced by this method has excellent particle homogeneity, there is a problem in that the synthesis temperature is high.

_{Japanese Patent Application Laid-Open No. 55-154319 discloses a method of manufacturing α-Fe 2} O ₃ as red iron oxide in an aqueous alkali solution together with an oxidizing agent after manufacturing magnetite through hydrothermal synthesis using iron ore or the like as a raw material.

US Patent No. 5,421,878 discloses a method for preparing _{α-Fe 2} O ₃ using an aqueous precipitation method using nanoparticles _{of γ-Fe 2} O _{3 or γ-FeOOH as seeds.} However, the method has a limitation in producing _{α-Fe 2} O ₃ nanoparticles having a particle size of 100 nm or less.

The Penniman method is disclosed in US Patent Nos. 1,327,061 and 1,368,748 as a method for preparing iron oxide red pigments by dissolving and oxidizing iron metal by adding iron oxide nuclei.

European Patent Publication EP 1106577A discloses a modified example of the Penniman method. This method involves the formation of iron oxide nanoparticles by the action of dilute nitric acid on metallic iron at high temperature. Although the production method does not have a mechanical mixing process of reactants, it has a long reaction time and low yield, and although it is an efficient method for producing iron oxide with excellent color and color through a wet process, It has a disadvantage of discharging a large amount _{of NO x} , which is a nitric oxide gas.

According to the Republic of Korea Patent Publication No. 10-2019-0094608 filed by the present inventors, a precipitate in the form of Fe(OH) _{3 is primarily obtained by using CaCO 3 as a precipitant in a mixed metal chloride aqueous solution, and after separating the precipitate} FeOOH can be obtained through additional dehydration and drying processes, and Fe ₂ O ₃ (hematite) can be obtained through high temperature heat treatment. However, this method has a problem in that additional heat treatment is required to obtain iron oxide and it is difficult to control the shape of the particles.

The present application seeks to provide a method for selectively preparing iron oxide from iron-containing mixed metal chlorides. Specifically, an object of the present invention is to provide a selective method for preparing iron oxide, comprising adding a carbonate and/or a base as a precipitation additive to an aqueous iron-containing mixed metal chloride solution and performing a hydrothermal reaction to obtain iron oxide.

However, the problems to be solved by the present application are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

One aspect of the present disclosure provides a method for selectively preparing iron oxide, comprising adding a carbonate and/or a base as a precipitation additive to an aqueous iron-containing mixed metal chloride solution and performing a hydrothermal reaction to obtain iron oxide

According to embodiments of the present application, after dissolving the mixed metal chlorides containing an iron component in water, an inexpensive carbonate and/or a base comprising a metal oxide and/or a metal hydroxide is added directly to the solution as a precipitation additive, By performing a hydrothermal reaction, high-purity iron oxide can be directly manufactured without separation and sintering processes in a single reaction vessel in which the reactants are added, thereby implementing a highly economical process.

According to the embodiments of the present application, in a single reaction vessel, size and shape are controlled through direct reaction of iron ions in the mixed metal chloride aqueous solution with the precipitation additive without additional addition of a reagent for controlling the shape and size. It is possible to manufacture high-purity iron oxide.

According to the embodiments of the present application, in the case of the hydrothermal synthesis method using a hydrothermal reactor, there is an advantage that not only the size and shape of the particles can be controlled, but also high-purity iron oxide can be manufactured without an additional separation or heat treatment process. Specifically, the size and shape of the obtained iron oxide particles can be controlled by adjusting the reaction conditions, in particular, temperature, pressure, and/or concentration of reactants. The selective production method of iron oxide according to the embodiments of the present application is much more economical because iron oxide can be produced in a single reactor compared to conventionally known methods that have to go through several steps.

According to the embodiments of the present application, a fairly high purity iron oxide can be obtained, and when ICP-MS analysis is performed after the reaction, metal ions other than iron contained in the initial mixed metal chloride aqueous solution are hardly detected. It is a fairly effective invention in In addition, in the case of iron oxide obtained according to the conventional method, it is difficult to control the size, and it is difficult to obtain iron oxide having a uniform color because the chromaticity or saturation of the iron oxide changes greatly depending on the size of the particles. Accordingly, according to the selective manufacturing method of iron oxide of the embodiments of the present application, high-quality iron oxide having a uniform shape and size controllable can be manufactured.

1 is an exemplary and schematic flowchart of a method for selectively producing iron oxide according to embodiments of the present application.
2 is an X-ray powder diffraction spectrum of _{iron oxide (Fe 2} O ₃ ) particles prepared according to Example 1 of the present application.
3 is an X-ray powder diffraction spectrum of _{iron oxide (Fe 2} O ₃ ) particles prepared according to Example 2 of the present application.
4A, 4B, and 4C are X-ray powder diffraction spectra of _{iron oxide (Fe 2} O ₃ ) particles, which are products prepared according to Examples 9, 14, and 15 of the present application, respectively.
5 is an electron micrograph _{of the iron oxide (Fe 2} O ₃ ) particles produced according to Example 1 of the present application.
6a and 6b are electron micrographs _{of iron oxide (Fe 2} O ₃ ) particles prepared according to Examples 12 and 13 with a shorter reaction time than Example 1 of the present application, respectively.
7a and 7b are electron micrographs _{of iron oxide (Fe 2} O ₃ ) particles prepared according to Example 9 and Example 11 in which the concentration of the mixed metal chloride aqueous solution was adjusted higher than in Example 1 of the present application; .

Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily carry out. However, the present application may be embodied in several different forms and is not limited to the embodiments and examples described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout this specification, when a part is "connected" to another part, this includes not only the case of being "directly connected", but also the case of being "electrically connected" with another element interposed therebetween. do.

Throughout this specification, when a member is said to be located “on” another member, this includes not only a case in which a member is in contact with another member but also a case in which another member is present between the two members.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

As used herein, the terms "about," "substantially," and the like are used in or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid in the understanding of the present application. It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable manner.

As used throughout this specification, the term “step of doing” or “step of” does not mean “step for”.

Throughout this specification, the term "combination(s) of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, It means to include one or more selected from the group consisting of the above components.

Throughout this specification, reference to “A and/or B” means “A or B, or A and B”.

Hereinafter, embodiments of the present application have been described in detail, but the present application may not be limited thereto.

A first aspect of the present application provides a method for selectively preparing iron oxide, comprising adding a carbonate and/or a base as a precipitation additive to an aqueous iron-containing mixed metal chloride solution and performing a hydrothermal reaction to obtain iron oxide.

In one embodiment of the present application, the iron oxide obtained by the manufacturing method may be iron oxide or iron hydroxide, for example, Fe ₂ O ₃ , Fe ₃ O ₄ , and may include one or more selected from FeOOH. However, it may not be limited thereto.

In one embodiment of the present application, the iron-containing mixed metal chloride aqueous solution is Mn, Al, Mg, Cr, Ca, V, Co, Mo, Nb, Ta, Bi, Si, Ti, Ni, Cu, and one or more metal ions selected from Zn, but may not be limited thereto.

In one embodiment of the present application, the iron content in the iron-containing mixed metal chloride aqueous solution is about 50 parts by weight to 100 parts by weight of the metal other than iron included in the iron-containing mixed metal chloride aqueous solution. It may be about 100 parts by weight, but may not be limited thereto. For example, the content of iron in the iron-containing mixed metal chloride aqueous solution is about 50 parts by weight or more, about 60 parts by weight or more based on 100 parts by weight of a metal other than iron included in the iron-containing mixed metal chloride aqueous solution. , about 70 parts by weight or more, about 80 parts by weight or more, about 90 parts by weight or more, about 50 parts by weight to about 100 parts by weight, about 50 parts by weight to about 90 parts by weight, about 50 parts by weight to about 80 parts by weight, about 50 parts by weight to about 70 parts by weight, about 50 parts by weight to about 60 parts by weight, about 60 parts by weight to about 100 parts by weight, about 60 parts by weight to about 90 parts by weight, about 60 parts by weight to about 80 parts by weight, about 60 parts by weight to about 70 parts by weight, about 70 parts by weight to about 100 parts by weight, about 70 parts by weight to about 90 parts by weight, about 70 parts by weight to about 80 parts by weight, about 80 parts by weight to about 100 parts by weight, about It may be 80 parts by weight to about 90 parts by weight, or about 90 parts by weight to about 100 parts by weight, but may not be limited thereto.

In one embodiment of the present application, the carbonate is Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , BeCO ₃ , CaCO ₃ , MgCO ₃ , and Al ₂ (CO ₃ ) _{3 It} contains at least one selected from may be, but may not be limited thereto.

In one embodiment of the present application, the base may include, but may not be limited to, a metal oxide and/or a metal hydroxide. For example, the metal oxide _{may include at least one selected from CaO, MgO, and Al 2} O ₃ , and the metal hydroxide is LiOH, NaOH, KOH, Ca(OH) ₂ , and Al(OH) _It may include one or more selected from 3, but may not be limited thereto.

In one embodiment of the present application, the precipitation additive may be added in a solid state or a liquid state, but is not limited thereto. Specifically, the base of the precipitation additive may be added as a solid state, but may not be limited thereto.

In one embodiment of the present application, the manufacturing method may be performed in a single reaction vessel. For example, the single reaction vessel may mean a single hydrothermal reactor.

In one embodiment of the present application, as shown in FIG. 1 , a carbonate CaCO ₃ or a base CaO, LiOH, KOH, or NaOH is added to the iron-containing mixed metal chloride aqueous solution as the precipitation additive, and hydrothermal reaction (hydrothermal reaction) reaction) to obtain high-purity iron oxide using a single reaction vessel or a single hydrothermal reactor without an additional separation and heat treatment process, but may not be limited thereto. For example, the iron oxide may be prepared according to the following process, but may not be limited thereto:

(a) preparing an iron-containing mixed metal chloride aqueous solution;

_{(b) adding CaCO 3 as} a carbonate or a base CaO, LiOH, KOH, or NaOH with an equivalent ratio to the iron-containing mixed metal chloride aqueous solution and mixing in a hydrothermal reactor; and

(c) obtaining iron oxide by hydrothermal reaction.

In one embodiment of the present application, the selective production method of the iron oxide comprises adding a carbonate and/or a base in a solid state as the precipitation additive to the iron-containing mixed metal chloride aqueous solution, so that the iron component in the metal chloride is subjected to a hydrothermal reaction. It may be preferentially crystallized by, but may not be limited thereto.

In one embodiment of the present application, the selective manufacturing method of the iron oxide may include selectively obtaining the iron oxide crystals whose size and/or shape are controlled by the manufacturing method, but may not be limited thereto. .

In one embodiment of the present application, the selective production method of iron oxide can obtain iron oxide with size and/or shape controlled in a single reaction vessel with high purity without adding a shape control reagent such as a surfactant through direct reaction in a single reaction vessel, This may not be limited.

In one embodiment of the present application, the crystal size of the obtained iron oxide may be controlled according to the concentration of the iron-containing mixed metal chloride. For example, the lower the concentration of the iron-containing mixed metal chloride is, the slower the precipitate is formed, so the crystal size of the iron oxide may be reduced, and the higher the concentration of the iron-containing mixed metal chloride is, the more the precipitate is formed. Since the rate is fast, the crystal size of the iron oxide may be increased, but may not be limited thereto.

In one embodiment of the present application, the type and yield of the obtained iron oxide may be controlled according to the concentration of the iron-containing mixed metal chloride aqueous solution and the amount of the precipitation additive added. For example, if the addition equivalent ratio of the precipitation additive is low compared to the concentration of the iron-containing mixed metal chloride, the iron oxide may not be formed as a precipitate, and the precipitation compared to the concentration of the iron-containing mixed metal chloride When the addition equivalent ratio of the additive is high, the iron oxide and other metal oxides may be formed together, but the present invention may not be limited thereto.

In one embodiment of the present application, the concentration of the mixed metal chloride aqueous solution may be about 0.1 M to about 5 M, but may not be limited thereto. For example, the concentration of the aqueous mixed metal chloride solution is about 0.1 M to about 5 M, about 0.1 M to about 4.5 M, about 0.1 M to about 4 M, about 0.1 M to about 3.5 M, about 0.1 M to about 3 M M, about 0.1 M to about 2.5 M, about 0.1 M to about 2 M, about 0.1 M to about 1.5 M, about 0.1 M to about 1 M, about 0.1 M to about 0.5 M, about 0.5 M to about 5 M, about 0.5 M to about 4.5 M, about 0.5 M to about 4 M, about 0.5 M to about 3.5 M, about 0.5 M to about 3 M, about 0.5 M to about 2.5 M, about 0.5 M to about 2 M, about 0.5 M to about 1.5 M, about 0.5 M to about 1 M, about 1 M to about 5 M, about 1 M to about 4.5 M, about 1 M to about 4 M, about 1 M to about 3.5 M, about 1 M to about 3 M, about 1 M to about 2.5 M, about 1 M to about 2 M, about 1 M to about 1.5 M, about 1.5 M to about 5 M, about 1.5 M to about 4.5 M, about 1.5 M to about 4 M, about 1.5 M to about 3.5 M, about 1.5 M to about 3 M, about 1.5 M to about 2.5 M, about 1.5 M to about 2 M, about 2 M to about 5 M, about 2 M to about 4.5 M, about 2 M to about 4 M, about 2 M to about 3.5 M, about 2 M to about 3 M, about 2 M to about 2.5 M, about 2.5 M to about 5 M, about 2.5 M to about 4.5 M, about 2.5 M to about 4 M, about 2.5 M to about 3.5 M, about 2.5 M to about 3 M, about 3 M to about 5 M, about 3 M to about 4.5 M, about 3 M to about 4 M, about 3 M to about 3.5 M, about 3.5 M to about 5 M, about 3.5 M to about 4.5 M, about 3.5 M to about 4 M, about 4 M to about 5 M, about 4 M to about 4.5 M, or from about 4.5 M to about 5 M, but may not be limited thereto. When the concentration of the mixed metal chloride aqueous solution is less than 0.1 M, the production rate of iron oxide may be too slow, and when the concentration of the mixed metal chloride aqueous solution is more than 5 M, the production rate of iron oxide is fast, but selective precipitation of iron oxide It may be difficult, and there may be problems in that it is difficult to control the size and/or shape of the iron oxide, but may not be limited thereto.

In one embodiment of the present application, the crystal size of the iron oxide obtained according to the manufacturing method may be about 100 nm to about 5 μm, but may not be limited thereto. For example, the crystal size of the iron oxide obtained according to the preparation method is about 100 nm to about 5 μm, about 100 nm to about 4 μm, about 100 nm to about 3 μm, about 100 nm to about 2 μm, about 100 nm to about 1 μm, about 100 nm to about 900 nm, about 100 nm to about 800 nm, about 100 nm to about 700 nm, about 100 nm to about 600 nm, about 100 nm to about 500 nm, about 100 nm to about 400 nm, about 100 nm to about 300 nm, about 100 nm to about 200 nm, about 200 nm to about 5 μm, about 200 nm to about 4 μm, about 200 nm to about 3 μm, about 200 nm to about 2 μm, about 200 nm to about 1 μm, about 200 nm to about 900 nm, about 200 nm to about 800 nm, about 200 nm to about 700 nm, about 200 nm to about 600 nm, about 200 nm to about 500 nm , about 200 nm to about 400 nm, about 200 nm to about 300 nm, about 300 nm to about 5 μm, about 300 nm to about 4 μm, about 300 nm to about 3 μm, about 300 nm to about 2 μm, about 300 nm to about 1 μm, about 300 nm to about 900 nm, about 300 nm to about 800 nm, about 300 nm to about 700 nm, about 300 nm to about 600 nm, about 300 nm to about 500 nm, about 300 nm to about 400 nm, about 400 nm to about 5 μm, about 400 nm to about 4 μm, about 400 nm to about 3 μm, about 400 nm to about 2 μm, about 400 nm to about 1 μm, about 400 nm to about 900 nm, about 400 nm to about 800 nm, about 400 nm to about 700 nm, about 400 nm to about 600 nm, about 400 nm about 500 nm, about 500 nm to about 5 μm, about 500 nm to about 4 μm, about 500 nm to about 3 μm, about 500 nm to about 2 μm, about 500 nm to about 1 μm, about 500 nm to about 900 nm, about 500 nm to about 800 nm, about 500 nm to about 700 nm, about 500 nm to about 600 nm, about 600 nm to about 5 μm, about 600 nm to about 4 μm, about 600 nm to about 3 μm , about 600 nm to about 2 μm, about 600 nm to about 1 μm, about 600 nm to about 900 nm, about 600 nm to about 800 nm, about 600 nm to about 700 nm, about 700 nm to about 5 μm, about 700 nm to about 4 μm, about 700 nm to about 3 μm, about 700 nm to about 2 μm, about 700 nm to about 1 μm, about 700 nm to about 900 nm, about 700 nm to about 800 nm, about 800 nm to about 5 μm, about 800 nm to about 4 μm, about 800 nm to about 3 μm, about 800 nm to about 2 μm, about 800 nm to about 1 μm, about 800 nm to about 900 nm, about 900 nm to about 5 μm, about 900 nm to about 4 μm, about 900 nm to about 3 μm, about 900 nm to about 2 μm, about 900 nm to about 1 μm, about 1 μm to about 5 μm, about 1 μm to about 4 μm , about 1 μm to about 3 μm, about 1 μm to about 2 μm, about 2 μm to about 5 μm, about 2 μm to about 4 μm, about 2 μm to about 3 μm, about 3 μm to about 5 μm, about 3 μm to about 4 μm, or about 4 μm to about 5 μm, but may not be limited thereto.

In one embodiment of the present application, the pH of the mixed metal chloride aqueous solution may be adjusted to about 1 or more or about 2 or more, but may not be limited thereto.

In one embodiment of the present application, the selective manufacturing method of the iron oxide may further include separating and drying the obtained iron oxide, but may not be limited thereto. In one embodiment of the present application, separating and drying the obtained iron oxide may further include the steps of filtration, washing, and drying, but may not be limited thereto.

In one embodiment of the present application, the reaction temperature of the hydrothermal reaction may be about 150 °C to about 250 °C, but may not be limited thereto. The reaction temperature may be a temperature at which the iron oxide is formed, but may not be limited thereto. For example, the reaction temperature of the hydrothermal reaction is from about 150 °C to about 250 °C, from about 150 °C to about 230 °C, from about 150 °C to about 210 °C, from about 150 °C to about 200 °C, from about 150 °C to about 180 °C , from about 150 °C to about 160 °C, from about 160 °C to about 250 °C, from about 160 °C to about 230 °C, from about 160 °C to about 210 °C, from about 160 °C to about 200 °C, from about 160 °C to about 180 °C, about 180 °C to about 250 °C, about 180 °C to about 230 °C, about 180 °C to about 210 °C, about 180 °C to about 200 °C, about 200 °C to about 250 °C, about 200 °C to about 230 °C, about 200 °C to about 210 °C, about 210 °C to about 250 °C, about 210 °C to about 230 °C, or about 230 °C to about 250 °C, but may not be limited thereto.

Following the exemplary embodiment of the present application, the reaction time of the hydrothermal reaction may be performed within about 1 hour to about 20 hours, but may not be limited thereto. For example, the reaction time of the hydrothermal reaction is about 1 hour to about 20 hours, about 1 hour to about 18 hours, about 1 hour to about 16 hours, about 1 hour to about 15 hours, about 1 hour to about 14 hours , about 1 hour to about 12 hours, about 1 hour to about 10 hours, about 1 hour to about 8 hours, about 1 hour to about 6 hours, about 1 hour to about 5 hours, about 1 hour to about 4 hours, about 1 hour to about 2 hours, about 2 hours to about 20 hours, about 2 hours to about 18 hours, about 2 hours to about 16 hours, about 2 hours to about 15 hours, about 2 hours to about 14 hours, about 2 hours to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 2 hours to about 6 hours, about 2 hours to about 5 hours, about 2 hours to about 4 hours, about 4 hours to about 20 hours, about 4 hours to about 18 hours, about 4 hours to about 16 hours, about 4 hours to about 15 hours, about 4 hours to about 14 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours , about 4 hours to about 8 hours, about 4 hours to about 6 hours, about 4 hours to about 5 hours, about 5 hours to about 20 hours, about 5 hours to about 18 hours, about 5 hours to about 16 hours, about 5 hours to about 15 hours, about 5 hours to about 14 hours, about 5 hours to about 12 hours, about 5 hours to about 10 hours, about 5 hours to about 8 hours, about 5 hours to about 6 hours, about 6 hours to about 20 hours, about 6 hours to about 18 hours, about 6 hours to about 16 hours, about 6 hours to about 15 hours, about 6 hours to about 14 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 20 hours, about 8 hours to about 18 hours, about 8 hours hours to about 16 hours, about 8 hours to about 15 hours, about 8 hours to about 14 hours, about 8 hours to about 12 hours, about 8 hours to about 10 hours, about 10 hours to about 20 hours, about 10 hours to about 18 hours, about 10 hours to about 16 hours, about 10 hours to about 15 hours, about 10 hours to about 14 hours, about 10 hours to about 12 hours, about 12 hours to about 20 hours, about 12 hours to about 18 hours hours, about 12 hours to about 16 hours, about 12 hours to about 15 hours, about 12 hours to about 14 hours, about 14 hours to about 20 hours, about 14 hours to about 18 hours, about 14 hours to about 16 hours, about 14 hours to about 15 hours, about 15 hours to about 20 hours, about 15 hours to about 18 hours, about 15 hours to about 16 hours, about 16 hours to about 20 hours, about 16 hours to about 18 hours, or about It may be 18 hours to about 20 hours, but may not be limited thereto. Here, if the reaction time is less than 1 hour, the particle size of the obtained iron oxide may be small and the yield may be low, and if the reaction time is more than 20 hours, the particle size of the obtained iron oxide may be large and the yield may be high, The reaction time may be a measure of the iron oxide crystallization process, but may not be limited thereto.

In one embodiment of the present application, by controlling the gas atmosphere in the single reaction vessel or hydrothermal reactor in the selective production method of iron oxide, the phase of the iron oxide particles is red Fe ₂ O ₃ and black Fe ₃ O ₄ , but may be manufactured separately, but may not be limited thereto. Specifically, when the heat treatment is performed in the internal gas that is an oxidizing atmosphere in the single reaction vessel or the hydrothermal reactor, Fe ₂ O _{3 as} red iron oxide is generated, and nitrogen or argon, which is an internal gas that is a reducing atmosphere, or hydrogen-containing atmosphere When reacted, Fe ₃ O ₄ phase may be generated together, but may not be limited thereto.

In one embodiment of the present application, the purity of the iron oxide obtained by the manufacturing method may be about 90% or more, but may not be limited thereto. For example, the purity of the iron oxide obtained by the above preparation method is about 90% or more, about 91% or more, about 92% or more, about 93% or more, about 94% or more, about 95% or more, about 96% or more. , about 97% or more, about 98% or more, or about 99% or more, but may not be limited thereto.

Hereinafter, the present application will be described in more detail using examples, but the following examples are only illustrative to help the understanding of the present application, and the content of the present application is not limited to the following examples.

[ Example ]

< Example 1>

_{After preparing carbon tetrachloride (TiCl 4} ) by the chlorination process of ilmenite ore, an aqueous chloride solution was prepared according to the composition of the mixed metal produced as a by-product after the chlorination process. Based on the ICP-MS analysis data of ferrite titanite, the weight ratio of metals contained in the aqueous solution was Fe (26.99%), Mn (0.99%), Al (0.77%), Mg (0.50%), and Cr, respectively. (0.42%). All standard solutions prepared based on the above weight ratio were prepared by dissolving anhydrous chloride of the corresponding metal in distilled water. Metal chlorides used in the preparation of the standard solution are FeCl ₃ , MnCl ₂ , AlCl ₃ , MgCl ₂ and CrCl ₂ . The concentration of the metal chloride standard solution was adjusted to 1.2 M. Then, 90 mL of distilled water was added to 10 mL of the standard solution to adjust the total volume of the solution to 100 mL. _{Then, 0.5 equivalent of calcium carbonate (CaCO 3} ) was added to 100 mL of the final solution, followed by stirring for 30 minutes, and the pH before and after addition of calcium carbonate was checked. Before adding the calcium carbonate, the pH of the mixed chloride aqueous solution was 1 or less, and after stirring for 30 minutes, the pH of the mixed chloride aqueous solution was increased to 1 or more. The color of the mixed chloride aqueous solution changed from dark brown to red. As soon as calcium carbonate was added to the mixed chloride aqueous solution, a large amount of carbon dioxide (CO ₂ ) was generated. The mixed aqueous chloride solution was placed in a hydrothermal synthesis reaction vessel and reacted at 150° C. to 200° C. for 10 hours. After completion of the reaction, the red precipitate was separated using a centrifuge and washed 3 times each with distilled water and ethanol. A crystal phase of the produced iron oxide was analyzed through an X-ray powder diffraction method ( FIG. 2 ), and the crystal structure of the iron oxide was confirmed to have _{Fe 2} O _{3 (hematite) through the analysis result.} In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles with an average size of 1 μm (distribution: in the range of 0.8 μm to 1.2 μm) through a scanning electron microscope ( FIG. 5 ). As a result of analyzing the composition of the obtained iron oxide through ICP-MS, the purity was analyzed to be about 99% or more. The amount of produced Fe ₂ O ₃ is 0.802 g and the yield is 91.2% based on iron.

< Example 2>

In the preparation of an aqueous chloride solution containing mixed metals, trace elements Ca (0.20%), V (0.12%), Nb (0.082%), and Co (0.0073%) based on ICP-MS analysis data of iron dioxide Iron oxide was synthesized in the same manner as in Example 1, except that , was additionally added. The crystal phase of the produced iron oxide was analyzed through X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ ( FIG. 3 ). In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.804 g and the yield is 91.3% based on iron.

< Example 3>

Iron oxide was synthesized in the same manner as in Example 1, except that calcium oxide (CaO) was used instead of calcium carbonate (CaCO _{3 ).} Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. The crystal phase of the produced iron oxide was analyzed by X-ray diffraction method, and it was confirmed that the crystal structure of the iron oxide had Fe ₂ O ₃ through the analysis result. In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.812 g and the yield is 92.3% based on iron.

< Example 4>

Iron oxide was synthesized in the same manner as in Example 1, except that potassium hydroxide (KOH) was used instead of calcium carbonate (CaCO _{3 ).} Specifically, 1 equivalent of potassium hydroxide was added to an aqueous chloride solution containing a mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. The crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ . In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.798 g and the yield is 90.8% based on iron.

< Example 5>

Iron oxide was synthesized in the same manner as in Example 1, except that lithium hydroxide (LiOH) was used instead of calcium carbonate (CaCO _{3 ).} Specifically, 1 equivalent of lithium hydroxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. The crystal phase of the produced iron oxide was analyzed by X-ray diffraction method, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ . In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.802 g and the yield is 91.2% based on iron.

< Example 6>

Iron oxide was synthesized in the same manner as in Example 1, except that sodium hydroxide (NaOH) was used instead of calcium carbonate (CaCO _{3 ).} Specifically, 1 equivalent of sodium hydroxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. The crystal phase of the produced iron oxide was analyzed by X-ray diffraction method, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ . In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.805 g and the yield is 91.6% based on iron.

< Example 7>

Iron oxide was synthesized in the same manner as in Example 1, except that a 1.2 M single iron chloride aqueous solution was prepared and used using only _{FeCl 3} as the metal chloride during the preparation of the standard solution. It was confirmed that the pH of the single iron chloride aqueous solution prepared as described above was 1 or less, and after adding 0.5 equivalent of calcium carbonate and stirring for 30 minutes, it was confirmed that the pH of the single chloride aqueous solution was 2 or more. A crystal phase of the produced iron oxide was analyzed by an X-ray diffraction method, and it was confirmed that the crystal structure had Fe ₂ O ₃ through the analysis result. The amount of produced Fe ₂ O ₃ is 0.808 g and the yield is 91.9% based on iron.

< Example 8>

Iron oxide was synthesized in the same manner as in Example 1, except that 10 mL of a 2.4 M standard solution was used and a mixed chloride aqueous solution having a double concentration was used. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. A crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ . In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles with an average size of 2 μm through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.802 g and the yield is 91.2% based on iron.

< Example 9>

Iron oxide was synthesized in the same manner as in Example 1, except that a 4-fold higher concentration of a mixed chloride aqueous solution was used using 10 mL of a 4.8 M standard solution. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. A crystal phase of the produced iron oxide was analyzed by X-ray diffraction method (FIG. 4a), and the crystal structure of the iron oxide was confirmed to have _{Fe 2} O _{3 through the analysis result.} In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles with an average size of 4 μm through a scanning electron microscope. The amount of produced Fe ₂ O ₃ was 0.809 g and the yield was 92.0% based on iron.

< Example 10>

Iron oxide was synthesized in the same manner as in Example 1, except that a mixed chloride aqueous solution having a low concentration of 1/2 was used using 10 mL of a 0.6 M standard solution. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or higher. A crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ . In addition, it was confirmed that the particles were synthesized into non-uniform cube-shaped particles with a size of 800 nm to 1.5 μm through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.812 g and the yield is 92.3% based on iron.

< Example 11>

Iron oxide was synthesized in the same manner as in Example 1, except that a mixed chloride aqueous solution having a low concentration of 1/4 was used using 10 mL of a 0.3 M standard solution. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. A crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ . In addition, it was confirmed that the particles were synthesized into particles with a size of 300 nm to 1 μm in the shape of a non-uniform cube through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.813 g and the yield is 92.5% based on iron.

< Example 12>

Iron oxide was synthesized in the same manner as in Example 1, except that the reaction time was reduced to 2 hours. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. A crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ . In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles having an average size of 600 nm through a scanning electron microscope (FIG. 6a). The amount of produced Fe ₂ O ₃ is 0.820 g and the yield is 92.3% based on iron.

< Example 13>

Iron oxide was synthesized in the same manner as in Example 1, except that the reaction time was reduced to 1 hour. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. The crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed that the crystal structure of the iron oxide had Fe ₂ O ₃ through the analysis result. In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles with an average size of 300 nm through a scanning electron microscope (FIG. 6b). The amount of produced Fe ₂ O ₃ is 0.817 g and the yield is 92.9% based on iron.

< Example 14>

Iron oxide was synthesized in the same manner as in Example 1, except that the reaction time was changed to 4 hours at a reaction temperature of 140°C. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was around 1 to 2. The crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ ( FIG. 4b ). In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles with an average size of 1.5 μm through a scanning electron microscope. The amount of produced Fe ₂ O ₃ was 0.809 g and the yield was 92.0% based on iron.

< Example 15>

Iron oxide was synthesized in the same manner as in Example 1, except that the reaction time was changed to 2 hours at a reaction temperature of 220°C. Specifically, 0.5 equivalent of calcium oxide was added to the aqueous chloride solution containing the mixed metal prepared in the same manner as in Example 1, and after stirring for 30 minutes, it was confirmed that the pH was 2 or more. The crystal phase of the produced iron oxide was analyzed by X-ray diffraction, and it was confirmed through the analysis result that the crystal structure of the iron oxide had Fe ₂ O ₃ ( FIG. 4c ). In addition, it was confirmed that the particles were synthesized into uniform cube-shaped particles through a scanning electron microscope. The amount of produced Fe ₂ O ₃ is 0.892 g and the yield ratio is 99.6% based on iron.

< Experimental example 1>

The oxide was synthesized in the same manner as in Example 1, and water was evaporated from the supernatant separated using a centrifuge in the process to obtain a precipitate. The crystal phase of the precipitate was analyzed through X-ray diffraction method, and it was confirmed that calcium chloride hydrate (CaCl ₂ (H ₂ O) ₄ ) was generated through the analysis result.

The above result is an analysis of the chemical species present in the supernatant except iron oxide prepared by the hydrothermal reaction. When the hydrothermal reaction is performed using calcium carbonate as a precipitation additive from iron-containing mixed metal chloride, iron oxide and calcium chloride form means obtained.

The foregoing description of the present application is for illustration, and those of ordinary skill in the art to which the present application pertains will understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and likewise components described as distributed may also be implemented in a combined form.

The scope of the present application is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present application. .

Claims (14)

adding a carbonate and/or a base as a precipitation additive to an aqueous iron-containing mixed metal chloride solution and performing a hydrothermal reaction to obtain iron oxide
A method for selectively producing iron oxide, comprising a.
The method of claim 1,
The iron oxide obtained by the above production method is Fe ₂ O ₃ , Fe ₃ O ₄ , and FeOOH, the selective method for producing iron oxide comprising at least one selected from.
The method of claim 1,
The iron-containing mixed metal chloride aqueous solution contains at least one metal selected from Mn, Al, Mg, Cr, Ca, V, Co, Mo, Nb, Ta, Bi, Si, Ti, Ni, Cu, and Zn in addition to iron ions. A method for selectively producing iron oxide, which further comprises ions.
4. The method of claim 3,
The content of the iron contained in the iron-containing mixed metal chloride aqueous solution is 50 parts by weight to 100 parts by weight based on 100 parts by weight of the metal other than iron contained in the iron-containing mixed metal chloride aqueous solution, iron oxide selective manufacturing method.
The method of claim 1,
The carbonate is Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , BeCO ₃ , CaCO ₃ , MgCO ₃ , and Al ₂ (CO ₃ ) ₃ The selective preparation of iron oxide comprising at least one selected from Way.
The method of claim 1,
Wherein the base comprises a metal oxide and/or a metal hydroxide, the selective method for producing iron oxide.
7. The method of claim 6,
The metal oxide is CaO, MgO, and Al ₂ O _{3 A} method for selectively producing iron oxide comprising at least one selected from the group consisting of.
7. The method of claim 6,
The metal hydroxide is LiOH, NaOH, KOH, Ca(OH) ₂ , and Al(OH) _{3 A} method for selectively producing iron oxide comprising at least one selected from the group consisting of.
The method of claim 1,
The method for the selective production of iron oxide, wherein the production method is carried out in a single reaction vessel.
The method of claim 1,
A method for selectively producing iron oxide, comprising selectively obtaining the crystals of the iron oxide whose size and/or shape are controlled by the production method.
The method of claim 1,
The method for selectively producing iron oxide, wherein the crystal size of the obtained iron oxide is controlled according to the concentration of the iron-containing mixed metal chloride.
The method of claim 1,

The selective production method of iron oxide, the type and yield of the iron oxide obtained is controlled according to the concentration of the iron-containing mixed metal chloride aqueous solution and the amount of the precipitation additive added.
The method of claim 1,
The iron-containing mixed metal chloride aqueous solution has a concentration of 0.1 M to 5 M, a selective method for producing iron oxide.
The method of claim 1,
The crystal size of the iron oxide obtained according to the production method is 100 nm to 5 μm, the selective production method of iron oxide.

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