阅读说明：本技术 一种金属铁及其制备方法 (Metallic iron and preparation method thereof ) 是由 黄博 谭喆 高俊云 佘威岑 于 2021-09-07 设计创作，主要内容包括：本发明公开一种金属铁及其制备方法,其中,一种金属铁的制备方法以γ-Fe-(2)O-(3)和碳为主要原料,制备获得金属铁,制备方法具体包括以下步骤,配入预设摩尔比的γ-Fe-(2)O-(3)和碳,将γ-Fe-(2)O-(3)和碳进行混料,充分混匀,将充分混匀的γ-Fe-(2)O-(3)和碳放入高温真空炉中进行保温和固相反应,反应完成后在惰性气体中进行冷却,以得到金属铁。该制备方法需要的温度条件远远低于现有技术中的1200℃,反应的温度要求越低,需要消耗的能源就越少,从而极大降低了能耗,且该反应减少了危险气体的排放量,减少对环境的污染。(The invention discloses metallic iron and a preparation method thereof, wherein the preparation method of the metallic iron is gamma-Fe 2 O 3 And carbon as main material to obtain iron metal, and the preparation process includes the following steps of compounding gamma-Fe in certain molar ratio 2 O 3 And carbon, with gamma-Fe 2 O 3 Mixing with carbon, mixing well, and mixing well gamma-Fe 2 O 3 And putting the carbon and the carbon into a high-temperature vacuum furnace for heat preservation and solid-phase reaction, and cooling in inert gas after the reaction is finished to obtain the metallic iron. The temperature condition required by the preparation method is far lower than 1200 ℃ in the prior art, and the lower the temperature requirement of the reaction is, the less energy is required to be consumed, so that the energy consumption is greatly reduced, the discharge amount of dangerous gas is reduced by the reaction, and the pollution to the environment is reduced.)

1. The preparation method of the metallic iron is characterized in that the preparation method uses gamma-Fe₂O₃And carbon as a main raw material, and preparing the metal iron, wherein the preparation method specifically comprises the following steps:

step 1: the gamma-Fe with a preset molar ratio is added₂O₃And the carbon;

step 2: subjecting said gamma-Fe to₂O₃Mixing the carbon and the mixture, and fully and uniformly mixing;

and step 3: mixing the gamma-Fe fully and uniformly₂O₃And putting the carbon into a high-temperature vacuum furnace for heat preservation and solid phase reaction;

and 4, step 4: after the reaction is completed, cooling is performed in an inert gas to obtain metallic iron.

2. The method according to claim 1, wherein the predetermined molar ratio of γ -Fe2O3 to carbon in step 1 is 1:50 to 1: 3.

3. The method for preparing metallic iron according to claim 1, wherein the mixing manner in the step 2 includes grinding, stirring, and ball milling.

4. The method for preparing metallic iron according to claim 1, wherein the incubation and reaction conditions in step 3 are as follows: keeping the temperature for 18 to 80 hours at the temperature of between 430 and 700 ℃.

5. The method for preparing metallic iron according to claim 1, wherein the incubation and reaction conditions in step 3 are as follows: keeping the temperature at 430 ℃ for 80 h.

6. The method for producing metallic iron according to claim 1, wherein the cooling conditions in step 4 are: cooling to 20-50 ℃ in inert gas.

7. The method according to claim 1, wherein the inert gas in the step 4 comprises nitrogen and/or nitrogen.

8. The method for preparing metallic iron according to claim 1, wherein the cooling in an inert gas after the completion of the reaction in the step 4 comprises:

and purging the reacted substances by using inert gas.

9. The preparation method of the metallic iron is characterized in that the metallic iron is prepared by taking Fe-MOF-74 as a raw material, and specifically comprises the following steps:

step 1: putting the Fe-MOF-74 into a high-temperature vacuum furnace for heat treatment for 18-80h, wherein the temperature of the heat treatment is in the temperature range of 430-700 ℃;

step 2: after the reaction is completed, cooling is performed in an inert gas to obtain metallic iron.

10. Metallic iron produced according to the method of any one of claims 1 to 8, wherein the metallic iron has an Fe content of 90% to 95%, Fe₂O₃The content is 3% -7%, and the carbon content is 3% -7%.

Technical Field

The invention relates to the technical field of ferroalloy, in particular to metallic iron and a preparation method thereof.

Background

The iron-making technology is a key technology for maintaining the steel industry, wherein blast furnace iron making with a blast furnace as equipment is also an important link of steel production. Blast furnace iron smelting is a method for continuously producing liquid pig iron in a vertical reactor-blast furnace by using coke, iron-containing ore and flux, the operating temperature of the blast furnace iron smelting needs to reach 1200 ℃, a large amount of energy needs to be consumed, the energy efficiency is low, and a large amount of dangerous gas can be generated in the production process, so that the discharge amount of the dangerous gas is high. Therefore, how to prepare the metallic iron at low temperature becomes a technical problem which needs to be solved urgently.

Disclosure of Invention

Therefore, there is a need for a metallic iron and a preparation method thereof, so as to solve the technical problems of the prior art that the metallic iron can be prepared at a high temperature and a large amount of energy is consumed.

The invention provides a preparation method of metallic iron, which uses gamma-Fe₂O₃And carbon as a main raw material, and preparing the metal iron, wherein the preparation method specifically comprises the following steps:

step 1: the gamma-Fe with a preset molar ratio is added₂O₃And the carbon;

step 2: subjecting said gamma-Fe to₂O₃Mixing the carbon and the mixture, and fully and uniformly mixing;

and step 3: mixing the gamma-Fe fully and uniformly₂O₃And putting the carbon into a high-temperature vacuum furnace for heat preservation and solid phase reaction;

and 4, step 4: after the reaction is completed, cooling is performed in an inert gas to obtain metallic iron.

Further, the gamma-Fe in step 1₂O₃And the preset molar ratio of the carbon is 1: 50-1: 3.

Further, the mixing mode in the step 2 comprises grinding, stirring and ball milling.

Further, the heat preservation and reaction conditions in step 3 are as follows: keeping the temperature for 18 to 80 hours at the temperature of between 430 and 700 ℃.

Further, the heat preservation and reaction conditions in step 3 are as follows: keeping the temperature at 430 ℃ for 80 h.

Further, the cooling conditions in step 4 are as follows: cooling to 20-50 ℃ in inert gas.

Further, the inert gas in step 4 comprises nitrogen and/or nitrogen.

Further, the cooling in an inert gas after the reaction in the step 4 comprises:

and purging the reacted substances by using inert gas.

In another embodiment, the invention further provides a preparation method of metallic iron, which takes Fe-MOF-74 as a raw material to prepare and obtain the metallic iron, and the preparation method specifically comprises the following steps:

step 1: putting the Fe-MOF-74 into a high-temperature vacuum furnace for heat treatment for 18-80h, wherein the temperature of the heat treatment is in the temperature range of 430-700 ℃;

step 2: after the reaction is completed, cooling is performed in an inert gas to obtain metallic iron.

In another embodiment, the invention also provides the metallic iron prepared by the method, wherein the prepared metallic iron contains 90-95% of Fe, 3-7% of Fe2O3 and 3-7% of carbon.

The invention provides a preparation method of metallic iron, which is to mix gamma-Fe with a preset molar ratio₂O₃Mixing with carbon, placing the mixture into a high-temperature vacuum furnace after fully mixing, carrying out heat preservation and solid-phase reaction, cooling in inert gas after the reaction is finished, thereby obtaining the metallic iron, carrying out the reaction in the high-temperature vacuum furnace, wherein the required temperature condition is far lower than 1200 ℃ in the prior art, the lower the temperature requirement of the reaction is, the less energy sources are required to be consumed, thereby greatly reducing the energy consumption, reducing the discharge amount of dangerous gases in the reaction, and reducing the pollution to the environment.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is an XRPD spectrum after heat treatment at 430 ℃ for various times in the examples of the present invention;

FIG. 2 is an XRPD spectrum obtained by refinement after heat treatment at 430 ℃ for 80h in example of the present invention;

FIG. 3 is an XRPD spectrum of a heat treatment at 200 deg.C, 300 deg.C, 400 deg.C for 36h in example of the present invention;

FIG. 4 is a TEM image of a heat treatment at 200, 300, 400 ℃ for 36 hours in an example of the present invention;

FIG. 5 is an XRPD spectrum of a heat treatment at 700 ℃ for 24h in example of the present invention;

FIG. 6 is a TEM image of a heat treatment at 700 ℃ for 24 hours in an example of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, "and/or" in the whole text includes three schemes, taking a and/or B as an example, including a technical scheme, and a technical scheme that a and B meet simultaneously; in addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The method for preparing metallic iron according to the present invention uses gamma-Fe₂O₃And carbon is used as a main raw material, the raw materials are uniformly mixed according to a preset proportion, the fully and uniformly mixed sample is placed into a high-temperature furnace for heat preservation and solid-phase reaction, and the reaction product is cooled in inert gas after the reaction is finished, so that the metallic iron is finally prepared. The method can convert gamma-Fe at low temperature₂O₃Reducing the iron into iron, greatly reducing the operation temperature and reducing the energy consumption compared with the blast furnace iron smelting technology in the prior art. Because the reaction is carried out in a milder environment, the produced harmful gas is less than that produced in blast furnace iron making in the prior art, and the harmful gas is easy to collect and treat, so that the pollution to the environment can be reduced. The method can improve the conversion rate of the ferric oxide, can reduce the production cost of the metallic iron, has higher commercial value, and is suitable for large-scale industrial production.

The method comprises the following steps:

step 1: the gamma-Fe with a preset molar ratio is added₂O₃And the carbon;

step 2: subjecting said gamma-Fe to₂O₃Mixing the carbon and the mixture, and fully and uniformly mixing;

and step 3: mixing the gamma-Fe fully and uniformly₂O₃And putting the carbon into a high-temperature vacuum furnace for heat preservation and solid phase reaction;

and 4, step 4: after the reaction is completed, cooling is performed in an inert gas to obtain metallic iron.

Specifically, the gamma-Fe is described in step 1₂O₃And the molar ratio of carbon is 1:50 to 1: 3. And 2, mixing the materials in a grinding, stirring and ball milling mode.

More specifically, the incubation and reaction conditions in step 3 are: keeping the temperature for 18 to 80 hours at the temperature of between 430 and 700 ℃. The heat preservation and reaction conditions in the step 3 are as follows: keeping the temperature at 430 ℃ for 80 h.

Further, the cooling conditions in step 4 are as follows: cooling to 20-50 ℃ in inert gas. The inert gas in step 4 comprises nitrogen and/or nitrogen. The cooling in the inert gas after the reaction in the step 4 comprises the following steps:

and purging the reacted substances by using inert gas. For example, the reaction-completed substance is purged with high-purity nitrogen gas.

Further, a method for preparing metallic iron, which takes Fe-MOF-74 as a raw material, and the method comprises the following steps:

step 1: putting the Fe-MOF-74 into a high-temperature vacuum furnace for heat treatment for 18-80h, wherein the temperature of the heat treatment is 430-700 ℃;

step 2: after the reaction is completed, cooling is performed in an inert gas to obtain metallic iron.

In particular, the gamma-Fe₂O₃And precursors of the carbon (comprising the metal organic framework MOF-74, MIL-101, MIL-100, MIL-88B, MIL-53, MOF-101, MOF-199, MOF-235, MOF-525, MOF-535, MOF-545, etc., and others, possibly converted to the gamma-Fe by various conditions₂O₃And the carbon), exemplified by MOF-74: anhydrous FeCl2(2.20g) and 1, 4-dihydroxyterephthalic acid (1.42g) were dissolved in 500ml of deoxygenated N, N-Dimethylformamide (DMF). The solution was reacted at 120 ℃ for 5 days under argon protection. The product was washed 3 times with deoxygenated DMF, soaked in deoxygenated methanol for 3 days, and the sample was vacuum dried at 60 ℃ to obtain the γ -Fe2O3 and the precursor of carbon.

In the metallic iron prepared by the method, the content of Fe is 90-95 percent, and the Fe₂O₃The content is 3% -7%, the carbon content is 3% -7%, and other trace elements can be ignored.

As shown in FIG. 1, the Fe-MOF-74 is subjected to heat treatment at 430 ℃ for 18-80h under vacuum condition, and the corresponding XRPD spectrum is obtained.

Can be analyzed by diffraction peak, and after 18h, the sample contains gamma-Fe₂O₃And Fe₃C, mixtures thereof. After 36h, Fe₃C disappears and alpha-Fe (body centered cubic lattice) appears. It is thus understood that gamma-Fe is produced by the thermal decomposition of Fe-MOF-74₂O₃Is one of Fe₃C-mediated Process, after 80 hours of Heat treatment, most of the gamma-Fe₂O₃Has been reduced to alpha-Fe.

As shown in FIG. 2, the XPRD spectrogram obtained at 80h is refined to obtain alpha-Fe and gamma-Fe₂O₃The weight ratio of (A) to (B) is 86.9: 13.1, thereby calculating Fe₂O₃The conversion to Fe was 91.2%.

Example 1

The Fe-MOF-74 is subjected to heat treatment at 200 ℃ and 300 ℃ respectively for 36 hours under vacuum conditions, and an XRPD spectrum (shown in figure 3) and a transmission electron microscope image (shown in figures 4a and b) are respectively obtained. Analysis of the XRPD pattern revealed that under both conditions, the crystal structure of the Fe-MOF-74 sample substantially disappeared (only weak diffraction peaks at individual positions). According to TEM images, no obvious particles exist at 200 ℃, and only a small amount of micro particles exist at 300 ℃, which is consistent with the result of spectrogram analysis.

Example 2

The Fe-MOF-74 was heat treated at 400 ℃ under vacuum for 36 hours to obtain an XRPD pattern (as shown in FIG. 3) and a transmission electron microscope image (as shown in FIG. 4 c). The analysis of XRPD spectrogram shows that gamma-Fe exists at 400 DEG C₂O₃Are present. From the TEM image, γ -Fe₂O₃Aggregates of NPs coexisted with the carbon remaining after decomposition of Fe-MOF-74, consistent with the results of the spectrum analysis, but alpha-Fe was not found.

Example 3

When Fe-MOF-74 is subjected to heat treatment at 700 ℃ for 24 hours under vacuum condition, the XRPD spectrum of the product (shown in figure 5) has obvious alpha-Fe existence, and the transmission electron microscope image shows that the alpha-Fe particle size is larger than 200nm (shown in figure 6).

Example 4

When Fe-MOF-74 is subjected to heat treatment for 36 hours at 600 ℃ under vacuum condition, the XRPD spectrum of the product shows that obvious alpha-Fe exists.

Example 5

When Fe-MOF-74 is subjected to heat treatment at 500 ℃ under vacuum for 48 hours, obvious alpha-Fe is also found in the XRPD pattern of the product.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.