AU2020101474A4

AU2020101474A4 - A Method for Preparing Nano α-Fe2O3 from Solid Waste Containing Iron under Solvent-free

Info

Publication number: AU2020101474A4
Application number: AU2020101474A
Authority: AU
Inventors: Suqin LI; Shaojun LUO; Lihua Wang
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2020-08-27
Anticipated expiration: 2028-07-24

Abstract

The invention provides a method for preparing nano c-Fe203 from solid waste containing iron under solvent free condition, belonging to technical fields of high value utilization of secondary resources and preparation of nano materials. The method comprises the following steps of: mixing and grinding an iron source and anhydrous sodium carbonate, placing the iron source and anhydrous sodium carbonate into a stainless steel reaction kettle, raising the temperature to 100-200°C, crystallizing for 36-72 hours, and rapidly cooling, washing and drying a filter cake after crystallization to obtain nano a-Fe203. Among them, the iron source used is iron salt soluble in water or solid waste containing more than 95% iron. The method uses a solvent-free method, has no secondary pollution in the preparation process, and is green and environment-friendly. The invention applies a solvent-free method to a process for synthesizing nano c-Fe203 by taking solid waste containing iron as raw materials for the first time. In the invention, iron-containing solid waste is used as a raw material to synthesize nano c-Fe203 by a solvent-free method, and the process is simple, the added value of the product is high, and the application range is wide. The technology can not only alleviate the resource and environmental problems caused by solid waste, but also prepare high value-added products with both economic and ecological benefits. Drawings of Descriptions a-Fe20 3 20 30 40 50 60 70 20(degree) Figure 1 5,OkV 9 3mrm x100k SE(M) 500nmn Figure 2 1/1

Description

Drawings of Descriptions

a-Fe203

30 40 50 60 70 20(degree)

Figure 1

,OkV 9 3mrm x100k SE(M) 500nmn

Figure 2

1/1

Descriptions

A Method for Preparing Nano a -Fe2O 3 from Solid Waste Containing Iron under Solvent-free

Technical Field

[0001] The invention relates to the technical fields of high value utilization of secondary resources and nano material preparation, in particular to a method for preparing nano a-Fe203 from solid waste containing iron under solvent-free.

Background Technology

[0002] With the rapid development of nano-technology, nano-materials have played an important role in society, human life, production economy and scientific and technological progress. The special interface structure of nano-materials makes them have physical and chemical properties that traditional materials do not have, and are widely used in medical treatment, electronics, bioengineering and other fields. Nanometer a -Fe203 is an important narrow band gap n-type semiconductor material, which has the advantages of good stability, non-toxicity, low cost and easy availability. When the size range of iron oxide is 0.1-100nm, the proportion of surface atomic number to total atomic number increases sharply, which will show some special properties possessed by nanomaterials, such as unique optical, magnetic and electrical properties. Nanometer a -Fe203has outstanding performance in inorganic dyes, catalysts, gas and humidity sensors, anodes of photoelectrochemical cells, photocatalytic reactions, water treatment and lithium ion batteries. At present, researchers have prepared a -Fe203nanomaterials with various morphologies by different methods and found that their properties are closely related to their structures and sizes. Therefore, the preparation of Nano ferric oxide with special structures is particularly important for the development of target functional devices.

[0003] The narrow band width (- 2.1eV) of nano a-Fe203 can fully utilize the visible light part of the solar light, but its photogenerated carriers have a short diffusion free path and excited electrons and holes are easy to recombine, thus limiting its photocatalytic performance. The difference in particle size morphology of a-Fe203nanomaterials will make the internal forbidden band structure and specific surface area of the materials different, thus affecting the absorption efficiency of light sources, the adsorption of surface substances and the photocatalytic performance of the materials. Therefore, it is of great significance to conduct in-depth research on the growth mechanism of a-Fe203, develop a simple and green synthesis method, and be able to controllably prepare a-Fe203 nanomaterials with specific particle size and morphology, and study their photoelectrocatalytic properties.

[0004] Generally, the preparation methods of nano a -Fe2 03 in the invention are chemical precipitation method, hydrothermal method and sol-gel method. Precipitation method can well control and promote the hydrolysis of iron salt, but the control requirement on hydrolysis temperature is relatively high. If the temperature is too high, the water evaporates too fast, the concentration of the system is difficult to control, and the hydrolysis of iron salt will also accelerate, resulting in uneven nucleation. If the temperature is too low, it is not conducive to the hydrolysis reaction. The nano-particles prepared by sol-gel method are uniform in size and relatively small in particle size, but the process is complex, requires a large amount of organic solvents, and has high cost. Hydrothermal method is currently a common method for preparing a -Fe203.It can well control the reaction process and ensure the uniformity of nucleation. The products are all nanoparticles. Adding surfactants can synthesize a-Fe203 nanoparticles with different morphologies for a variety of high-end materials. However, hydrothermal method cannot completely avoid the use of solvents in the process of preparing a -Fe 203 nanoparticles, generate a large amount of alkali-containing wastewater and reduce the space utilization rate of a -Fe203 nanoparticles synthesis equipment. The solvent-free method of this invention refers to the preparation process of nanometer a - Fe203 without any solvent, which is directly placed into a reactor after mixing and grinding, and then sealing and standing synthesis under a certain temperature. This process is simple and has high utilization rate of equipment. It is proposed for the first time in preparation of nano a -Fe203, and there is no report on synthesis of nano a Fe203 from solid waste containing iron under solvent-free.

Invention Summary

[0005] The technical problems to be solved by the invention is to provide a method for preparing

nano a -Fe203 from solid waste containing iron under solvent-free.

[0006] The method comprises the following steps:

[0007] (1) Mixing iron source and anhydrous sodium carbonate according to a certain proportion, and then grinding for 1-10 minutes to obtain a mixture;

[0008] (2) Putting the mixture obtained in the step (1) into a stainless steel reaction kettle, heating to 100-200°C, crystallizing for 36-72 hours, rapidly cooling, washing and drying filter cakes after crystallization to obtain nano a -Fe203.

[0009] The ratio of iron source to anhydrous sodium carbonate in step (1) is: n(Fe 3*)/n(CO3 2 -) 0.3~1.0.

[0010]The iron source in step (1) is soluble iron salt or solid waste with an iron content of more than 95%.

[0011] Firstly, solid waste containing iron is purified by superconducting separation technology, and then the purified solid waste is modified and acid leached to crystallize into FeCl3 crystals.

[0012] The modification is that the iron containing substances enriched is treated by high temperature heating at 400-600°C for 1-3 hours. Dissolving the iron containing substances modified with acid, heating and concentrating, cooling and crystallizing, filtering and drying to obtain iron salt crystals, which are used as the iron sources for preparing nano a-Fe203.

[0013]The preparation process of the invention uses various iron salts soluble in water and iron containing solid wastes soluble in acid as raw materials: (1) With soluble salt iron as raw material, the experiment can be directly carried out without pretreatment of raw materials. (2) When taking iron-containing solid wastes as raw materials, the raw materials must be pretreated in advance, compounds containing iron elements and simple substances are purified to a purity of more than 95%, and then the iron oxides need to be modified at high temperature so that all kind of Fe in solid waste is transformed into the form of Fe.

[0014] The technical scheme of the invention has the following beneficial effects:

[0015] (1) The invention provides a brand-new method for synthesizing nano a -Fe203, expands the range of raw materials, and finds new uses for iron-containing solid wastes.

[0016] (2) According to the method of the invention, nano a -Fe203 is prepared, and the raw materials of the reaction mixture do not contain solvents. This method can improve the utilization rate of nano a -Fe203 synthesis equipment, reduce production cost and reduce pollution in the production process.

[0017] (3) The invention completes the utilization of iron-containing solid waste with high added value.

Brief Description of Drawings

[0018] Fig. 1 is an x-ray diffraction spectrum of nano a -Fe203 synthesized by the method for preparing nano a -Fe203 in Embodiment 1 of the present invention;

[0019] Fig. 2 is an electron microscope view of nano a -Fe203 synthesized by the method for preparing nano a -Fe203 in Embodiment 1 of the present invention.

Detailed Description of the Presently Preferred Embodiments

[0020] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the drawings and specific embodiments.

[0021] The invention provides a method for preparing nano a -Fe203.

[0022] The method comprises the following steps of: firstly, mixing an iron source and anhydrous sodium carbonate according to a certain proportion, and then grinding for 1~10 minutes to obtain a mixture; then placing the obtained mixture into a stainless steel reaction kettle, heating to 100-200°C, crystallizing for 36-72 hours, and rapidly cooling, washing and drying filter cakes after crystallization to obtain nano a-Fe203.

[0023] Embodiment 1

[0024] Using FeC3-6H20 as raw material, 1.35g FeC13-6H20 crystal and 1.59g Na2CO3 were mixed and ground for 5 minutes. The mixture was placed in a sealed stainless steel reaction kettle and heated to 150°C for 54 hours. After crystallization, the filter cake is rapidly cooled, washed and dried to obtain a crystallized product. X-ray diffraction (XRD) tests show that the product is a-Fe203, and the crystal size of a-Fe203 is 15-20nm. The XRD pattern and electron microscope pattern are shown in figs. 1 and 2.

[0025] Embodiment 2

[0026] Iron mud is taken as a raw material, is modified at high temperature and dissolved by hydrochloric acid, is heated and concentrated, is cooled and crystallized, and is dried to obtain ferric trichloride crystals; 1.35g FeCl3-6H20 crystals are added with 1.59g Na2CO3 to be mixed and ground for 5 minutes; and the mixture is put into a sealed stainless steel reaction kettle to be heated to 150°C, kept at a constant temperature and crystallized for 54 hours. After crystallization, the filter cake is rapidly cooled, washed and dried to obtain a crystallized product. X-ray diffraction (XRD) tests show that the product is a-Fe203, and the crystal size of a-Fe203 is -20nm.

[0027] Embodiment 3

[0028] Converter ash is used as a raw material, iron-containing substances are separated by superconducting equipment, the iron-containing substances are dissolved by hydrochloric acid after being modified at high temperature, heated and concentrated, cooled and crystallized, ferric chloride crystals are obtained after drying, 1.35g FeC13-6H20 crystals are added with 1.59g Na2CO3, mixed and ground for 5 minutes, and the mixture is placed in a sealed stainless steel reaction kettle, heated to 150°C, kept at constant temperature, and crystallized for 54 hours. After crystallization, the filter cake is rapidly cooled, washed and dried to obtain a crystallized product. X-ray diffraction (XRD) tests show that the product is a-Fe203, and the crystal size of a-Fe203 is 15-20nm.

[0029] The above is a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and embellishments can be made without departing from the principles of the present invention. These improvements and embellishments should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing nano a-Fe203 from solid waste containing iron under solvent-free is characterized by comprising the following steps:

(1) (2) Mixing iron source and anhydrous sodium carbonate according to a certain proportion, and then grinding for 1-10 minutes to obtain a mixture;

(2) Putting the mixture obtained in the step (1) into a stainless steel reaction kettle, raising the temperature to 100-200°C, crystallizing for 36-72 hours, and rapidly cooling, washing and

drying filter cakes after crystallization to obtain nano a-Fe203.

2. The method for preparing nano a-Fe203 according to claim 1, characterized in that: the

ratio of iron source to anhydrous sodium carbonate in the step (1) is: n(Fe 3+)/n(C032-)_

0.3~1.0.

3. The method for preparing nano a-Fe203 according to claim 1, characterized in that: the iron source in the step (1) is iron salt soluble in water or solid waste with an iron content of more than 95%.

4. The method for preparing nano a-Fe203 according to claim 3 is characterized in that: the solid waste containing iron is firstly purified by superconducting separation technology, and then the iron containing substance enriched is modified and acid leached to crystallize into FeCl3 crystals.

5. The method for preparing nano a-Fe203 according to claim 4 is characterized in that: the purified solid waste is modified by adopting a high-temperature heating mode. The modification treatment temperature is between 400-600°C, and the treatment time is 1-3 hours.

2020101474 Drawings of Descriptions

Figure 1

Figure 2

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