FeP flake powder, method for preparing same, and use thereof in catalytic degradation of azo dyes

Abstract

This invention provides FeP flake powder, its preparation method, and its application in the catalytic degradation of azo dyes. Essentially, this invention provides a novel short-process technology for preparing FeP flake powder by melting and reducing high-phosphorus iron ore. It utilizes the phosphorus (P) element in the high-phosphorus iron ore to promote electron transfer and enhance catalytic degradation performance, transforming harmful P elements in the high-phosphorus iron ore into beneficial elements, thus achieving high-value utilization of the high-phosphorus iron ore. Single-roller rotary quenching and ultra-fast solidification refines the grains and increases reactive sites such as grain boundaries. Simultaneously, ball milling increases the activation energy and surface defects. The prepared novel FeP flake powder can effectively catalyze the degradation of azo dyes, with a degradation rate more than six times that of commercial iron powder.

Description

Technical Field

[0001] This invention relates to the field of fine chemical technology, specifically to a FeP flake powder, its preparation method, and its application in the catalytic degradation of azo dyes. Background Technology

[0002] Azo dye wastewater has become one of the major industrial wastewaters in my country. It has high color intensity, strong chemical stability, is difficult to degrade, and poses risks of carcinogenicity, teratogenicity, and mutagenicity, thus posing a serious threat to ecosystems and public health.

[0003] Currently, the main methods for treating azo dye wastewater include physical adsorption, chemical reduction, and biodegradation. Among these, zero-valent iron (ZVFe) is widely used in azo dye wastewater treatment due to its low cost, abundant resources, and non-toxicity. ZVFe can generate Fe in azo dye wastewater. 2+ / Fe 3+ Subsequently, it catalyzes the generation of highly oxidizing hydroxyl radicals, which then oxidize and degrade pollutants. Therefore, commercial iron powder is a recognized high-efficiency treatment material in the field of azo dye degradation. However, the preparation of commercial iron powder generally uses industrial pure iron as raw material, and after induction melting and remelting, it is prepared by atomization to obtain micron-sized iron powder. The preparation of industrial pure iron requires complex processes such as blast furnace reduction and converter refining, which are separated from the subsequent atomization process for iron powder preparation. This results in the need for remelting after the molten steel solidifies, leading to high energy consumption, emissions, and production costs.

[0004] In addition, existing patent technologies also disclose cases of using amorphous alloy strips to catalyze the degradation of azo dyes. For example, patent document CN113546655A discloses an Fe-Co-PC amorphous alloy catalyst for efficient dye degradation, its preparation method and application. It uses iron, cobalt, carbon and iron-phosphorus alloys to remelt and alloy, and then uses single-roll spin quenching to prepare amorphous strips for degrading azo dyes. This method also has the problem of separating the raw material preparation and strip preparation processes; moreover, in order to form amorphous strips, it is usually necessary to add a high content of non-metallic elements, and the purity requirements of the raw materials are also high. Its production cost is 3 to 5 times that of commercial iron powder. Summary of the Invention

[0005] Therefore, it is necessary to provide a FeP flake powder, its preparation method, and its application in the catalytic degradation of azo dyes.

[0006] The present invention adopts the following technical solution: This invention provides a FeP flake powder, which is mainly prepared by forming ore agglomerates with high-phosphorus iron ore and carbon reducing agent, drying and then melting and reducing, forming strips by single-roll quenching, and ball milling; wherein, the high-phosphorus iron ore contains not less than 70 wt% Fe2O3 and not less than 0.8 wt% P, and the C / O ratio of the high-phosphorus iron ore and carbon reducing agent is 0.6~1.0.

[0007] Preferably, the average particle size of the FeP flake powder is 100~300 μm.

[0008] Preferably, the reducing agent is selected from one or more of carbon powder, coke, and biochar.

[0009] This invention also provides a method for preparing FeP flake powder, comprising the following steps: Obtain high-phosphorus iron ore and reducing agent, wherein the high-phosphorus iron ore has an Fe2O3 content of not less than 70 wt% and a P content of not less than 0.8 wt%, and the raw materials are mixed according to a C / O ratio of 0.6~1.0; The mixed raw materials are pressed into ore pellets, dried and dehydrated, and then melted and reduced to obtain molten iron containing phosphorus. The molten iron containing P is quenched and formed into strip by single-roll spin quenching; The strip was ball-milled to obtain FeP flake powder.

[0010] This invention essentially proposes a novel short-process technology for preparing FeP flake powder by melting and reducing high-phosphorus iron ore. The specific process is as follows: high-phosphorus iron ore is melted and reduced with carbon to obtain P-containing molten iron, which is then directly formed into alloy strips using single-roll quenching technology, and finally ball-milled to obtain FeP flake powder.

[0011] Preferably, the melting reduction temperature is 1550~1650 ℃ and the duration is 1~2 h.

[0012] Preferably, a binder is added during the step of forming the mineral agglomerate.

[0013] Preferably, the process parameters for the single-roll spin-quenching forming of the strip are: temperature 1350~1400℃, sprayed onto the surface of a copper roller with a rotation speed of 3000~5000 r / min, and rapidly cooled to obtain a strip with a thickness of 20~30 μm.

[0014] Preferably, the process parameters for the ball mill are: ball-to-material ratio (4~8):1, rotation speed 200~300 r / min, and duration 2~3h.

[0015] This invention provides the application of FeP flake powder as a catalytic degradation reagent for azo dye wastewater.

[0016] This invention provides a reagent for the catalytic degradation of azo dye wastewater, comprising FeP flake powder.

[0017] Compared with the prior art, the core advantage of this invention is: The method for preparing FeP flake powder of the present invention is a new short-process technology with the following advantages: (1) The molten reduction process has the advantages of strong raw material adaptability, low emissions and flexible operation, and can process complex high-phosphorus oolitic hematite to reduce it to obtain P-containing molten iron; (2) The single-roller quenching process has the advantages of one-time forming and high efficiency, which is suitable for large-scale production, and ultra-fast solidification (10 6 K / s) can refine grains, increase reactive sites such as grain boundaries, and improve catalytic degradation performance; (3) ball milling process has the advantages of simple equipment and low production cost, while it can improve the reaction activation energy of iron powder and increase surface defects, thereby improving catalytic performance.

[0018] Compared with existing commercial iron powder production processes, this invention prepares phosphorus-containing flake iron powder from high-phosphorus iron ore metallurgical materials through an integrated process, avoiding solidification and remelting, and has the advantages of energy saving and emission reduction. At the same time, it realizes the high-value utilization of high-phosphorus iron ore resources, has high catalytic activity, and can effectively degrade azo dye wastewater. Attached Figure Description

[0019] Figure 1 A schematic diagram of a new short-process technology for preparing FeP flake powder by melting and reducing high-phosphorus iron ore.

[0020] Figure 2 SEM images of commercially available iron powder (referred to as Comparative Example 1) and the product prepared in Example 1 are shown.

[0021] Figure 3 A statistical graph showing the reaction time-reaction concentration to initial concentration ratio in the azo dye degradation performance test of commercially available iron powder and the products prepared in Examples 1 and 2.

[0022] Figure 4 The graph shows the logarithm of the ratio of reaction time to initial concentration and its linear fit in the degradation performance test of commercially available iron powder, the products prepared in Examples 1 and 2, and azo dyes. Detailed Implementation

[0023] like Figure 1 As shown, the technical concept of this invention lies in providing a novel short-process technology for preparing FeP flake powder by melting and reducing high-phosphorus iron ore. This involves preparing phosphorus-containing molten iron through the melting reaction of high-phosphorus iron ore and a reducing agent, obtaining alloy strips through single-roll quenching, and then ball milling to obtain flake iron powder. The FeP flake iron powder prepared by this invention exhibits superior degradation performance against azo dyes.

[0024] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. The following embodiments are only used to illustrate the present invention, and are not intended to limit the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention. In the embodiments of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the embodiments of the present invention, unless specifically specified, the technical means used are conventional means well known to those skilled in the art.

[0025] During the testing, XRD (X-ray diffraction); SEM (scanning electron microscopy); ICP (inductively coupled plasma atomic emission spectrometry); and CS (carbon and sulfur analyzer) were used. k obs : Apparent degradation rate coefficient.

[0026] Explanation of the source of key materials: High-phosphorus iron ore, source: Hubei West High-phosphorus Iron Ore of Wuhan Iron and Steel Co., Ltd.

[0027] The content statistics after testing are shown in the table below: Table 1. Statistical table of main material composition of high-phosphorus iron ore The following example illustrates this.

[0028] Example 1 This embodiment provides a method for preparing FeP flake powder, including the following steps: (1) Raw material preparation: According to C / O=0.8 (the molar ratio of carbon in the reducing agent to oxygen in the iron oxide), accurately weigh 9.58 kg of high-phosphorus iron ore and 0.14 kg of carbon powder.

[0029] (2) Ore agglomeration preparation: The high-phosphorus iron ore and carbon powder are mixed evenly, and then moistened with a starch solution accounting for 2% of the total amount of high-phosphorus iron ore and carbon powder. The mixture is then pressed into ore pellets with a diameter of 10 mm and a height of 12 mm.

[0030] (3) Drying and reduction: After the ore pellets are dried at 105℃ for 12 hours, they are placed in an electric arc furnace and heated to a preset temperature of 1600℃. The temperature is maintained for 1-2 hours for melting and reduction to obtain molten iron containing phosphorus.

[0031] (4) Single-roll rotary quenching and ball milling: Molten iron containing phosphorus (P) is transferred to a spraying ladle, and the temperature is controlled at 1350~1400℃. It is then sprayed onto the surface of a high-speed rotating copper roller (3000~5000 r / min) for rapid cooling to obtain an alloy strip with a thickness of 20~30 μm. The obtained alloy strip is then placed in a ball mill and ball-milled at a ball-to-material ratio of (4~8):1 and a rotation speed of 200~300 r / min for 2~3 h to obtain FeP flake powder with a particle size of approximately 200 μm.

[0032] Using commercially available iron powder (referred to as Comparative Example 1) as a control, the product prepared in Example 1 was characterized for particle size and morphology, and the results are as follows: Figure 2 As shown.

[0033] Depend on Figure 2 It can be seen that the FeP flake powder obtained in this embodiment is a typical flake with a particle size of about 200 μm and a thickness of about 20 μm; the particle size of commercial iron powder is about 20 μm.

[0034] Example 2 This embodiment provides a method for preparing FeP flake powder, the process steps of which are basically the same as those in Example 1, the only difference being: In step (1), 9.39 kg of high-phosphorus iron ore and 0.15 kg of carbon powder are accurately weighed according to C / O=1.0 (the molar ratio of carbon in the reducing agent to oxygen in the iron oxide).

[0035] Tests showed that the FeP flake powder obtained in this embodiment had the same particle size and morphology as in Example 1.

[0036] The FeP flake powder prepared in Examples 1 and 2 was further tested for composition. The Fe and P contents were obtained by ICP test and the C contents were obtained by CS analyzer. The Fe yield was calculated based on the tested FeP flake powder composition.

[0037] The formula for calculating Fe recovery rate is: FeP flake powder mass × Fe mass percentage in FeP flake powder / high-phosphorus iron ore mass × Fe mass percentage in high-phosphorus iron ore.

[0038] The results are shown in Table 2 below: Table 2 Elemental composition and Fe yield statistics of FeP flake powder Using commercially available iron powder (referred to as Comparative Example 1) as a control, the azo dye degradation performance of the FeP flake powders prepared in Examples 1 and 2 was tested: Take 100 L of methyl orange solution with a concentration of 50 mg / L, add 0.2 kg of FeP flake powder, and shake at room temperature; after 1 h, the solution color becomes significantly lighter, and after 2 h, it becomes completely transparent; the degradation reaction performance is compared with commercial iron powder by UV spectrophotometer.

[0039] Test statistics results are as follows Figure 3 and Figure 4 As shown.

[0040] Depend on Figure 3 It can be seen that after 2 hours of degradation by commercial iron powder, the residual concentration of methyl orange exceeded 70%. The FeP flake powder prepared in the examples showed a significantly faster decrease in methyl orange concentration after catalytic degradation of the methyl orange solution. This indicates that the FeP flake powder prepared in the above examples is more effective than commercial iron powder in catalytic degradation of methyl orange azo dye. Furthermore, the degradation effect of Example 1 (FeP flake powder with C / O=0.8) is better than that of Example 2 (FeP flake powder with C / O=1.0).

[0041] Based on the analysis of the change in methyl orange solution concentration with degradation time, the degradation reaction conforms to the first-order reaction model in chemical reaction kinetics, as shown in the following expression: ln( c 0 / c t ) = k obs / t In the formula: c t The concentrations of methyl orange solutions at different degradation times; c 0 represents the initial concentration of the methyl orange solution; k obs The apparent degradation rate coefficient; t For different degradation times.

[0042] Linear fitting yielded k obs like Figure 4 As shown.

[0043] Depend on Figure 4 It can be seen that the FeP flake powder prepared in the above embodiments... k obs The degradation rate of FeP flakes with C / O = 0.8 was significantly larger than that of commercial iron powder. The degradation rate of FeP flakes with C / O = 0.8 in Example 1 was 10.9 times that of commercial iron powder, and the degradation rate of FeP flakes with C / O = 1.0 in Example 2 was 6.7 times that of commercial iron powder.

[0044] Example 3 Following the process steps of Example 1, this example investigates the effects of different C / O ratios (0.6, 0.7, 0.8, 0.9, and 1.0) in the mixing of high-phosphorus iron ore and carbon powder raw materials on the iron yield in the preparation of FeP flake powder and on the degradation performance of azo dyes. The results are shown in Table 3 below: Table 3. Statistical table of FeP flake powder prepared under different C / O ratio conditions. As can be seen from the table above, with the increase of C / O ratio, the yield of Fe in FeP flake powder increases, the C content increases, and the degradation efficiency decreases.

[0045] Example 4 Referring to the process steps of Example 1, this example investigates the effects of high-phosphorus iron ore and different carbon reducing agents (coke, biomass) on the yield of FeP flake iron powder and its degradation performance on azo dyes.

[0046] The experimental results show that, under the same C / O ratio, the type of reducing agent has little effect on the Fe yield and degradation performance.

[0047] Example 5 Referring to the process steps (1) to (3) of Example 1, this example further uses an atomization device to directly prepare the obtained P-containing molten iron into spherical powder, resulting in a smaller powder particle size.

[0048] However, tests showed that the catalytic degradation performance of methyl orange azo dye was worse than that of ball-milled flake powder.

[0049] Through the above experimental examples, the research team found that: 1. The FeP flake powder process of this invention requires controlling parameters such as the phosphorus content, melting and reduction temperature, and carbon-oxygen ratio during the high-phosphorus iron ore carbon-based molten reduction process. This invention proposes using high-phosphorus iron ore to prepare FeP flake powder for efficient catalytic degradation of azo dyes, one of the key points being the use of phosphorus in high-phosphorus iron ore to enhance the catalytic degradation effect.

[0050] 2. The short-process preparation process of FeP flake powder proposed in this invention first uses single-roller rotary quenching technology to prepare an extremely thin strip from the molten reduction mother liquor of high-phosphorus iron ore, and then uses ball milling to crush it into flake powder. The new process integrates two mature technologies and has the advantages of high efficiency, low cost and easy operation.

[0051] 3. The FeP flake powder of this invention exhibits significant advantages in catalytic degradation of azo dyes, with a fast reaction rate and simple operation. Fe in the FeP flake powder reacts with the azo dye solution to produce Fe... 2+ / Fe 3+Catalyzing the generation of hydroxyl radicals (·OH), ·OH oxidizes the azo bonds (-N=N-) in azo dye molecules, causing them to break and degrade into harmless small molecules; P element promotes Fe by accelerating electron transfer. 2+ / Fe 3+ Cycle to improve catalytic efficiency.

[0052] It should be noted that the above embodiments are only for further elaboration and explanation of the technical solution of the present invention, and are not intended to further limit the technical solution of the present invention. The method of the present invention is only a preferred embodiment and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A FeP flake powder, characterized in that, It is prepared by forming ore agglomerates with high-phosphorus iron ore and reducing agent, drying and then melting and reducing, forming strip by single-roll quenching, and ball milling; wherein, the high-phosphorus iron ore contains not less than 70 wt% Fe2O3 and not less than 0.8 wt% P, and the C / O ratio of the high-phosphorus iron ore to the reducing agent is 0.6~1.

0.

2. The FeP flake powder according to claim 1, characterized in that, The average particle size of FeP flake powder is 100~300 μm.

3. The FeP flake powder according to claim 1, characterized in that, The reducing agent is selected from one or more of carbon powder, coke, and biochar.

4. A method for preparing FeP flake powder, characterized in that, Includes the following steps: Obtain high-phosphorus iron ore and reducing agent, wherein the high-phosphorus iron ore has an Fe2O3 content of not less than 70 wt% and a P content of not less than 0.8 wt%, and the raw materials are mixed according to a C / O ratio of 0.6 to 1.0; The mixed raw materials are pressed into ore pellets, dried and dehydrated, and then melted and reduced to obtain molten iron containing phosphorus. The molten iron containing P is quenched and formed into strip by single-roll spin quenching; The strip was ball-milled to obtain FeP flake powder.

5. The method for preparing FeP flake powder according to claim 4, characterized in that, The melting and reduction process takes place at a temperature of 1550~1650 ℃ for 1~2 h.

6. The method for preparing FeP flake powder according to claim 4, characterized in that, A binder is added during the process of forming the mineral clusters.

7. The method for preparing FeP flake powder according to claim 4, characterized in that, The process parameters for the single-roll spin-quenching forming of the strip are: temperature 1350~1400℃, sprayed onto the surface of a copper roller with a rotation speed of 3000~5000 r / min, and cooled to obtain a strip with a thickness of 20~30 μm.

8. The method for preparing FeP flake powder according to claim 4, characterized in that, The process parameters for the ball mill are: ball-to-material ratio (4~8):1, rotation speed 200~300 r / min, and duration 2~3 h.

9. The application of the FeP flake powder according to any one of claims 1 to 3 as a catalytic degradation reagent for azo dye wastewater.

10. A reagent for the catalytic degradation of azo dye wastewater, characterized in that, Contains the FeP flake powder according to any one of claims 1 to 3.

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