A method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4

Abstract

This invention discloses a method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4, comprising: (1) uniformly mixing multiple typical niobium minerals with a sulfiding agent, a reducing agent, and a modifier to obtain a mixture; and (2) reacting the mixture at 1050~1350℃ under a protective atmosphere until complete to obtain a product containing FeNb2S4. The mineral raw materials of this invention are widely available, the process route is simple, suitable for large-scale production, and the production cost is lower than existing methods. The process is highly adaptable to resource diversity, providing an economically feasible new path for the industrial production of niobium-based electrocatalysts.

Description

Technical Field

[0001] This invention relates to the fields of metallurgy and mineral processing, and in particular to a method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4. Background Technology

[0002] Niobium is a strategically critical metal, widely used in high-end alloys due to its excellent physicochemical properties. The main minerals in which niobium is found in nature include calcite, columbite, pyrochlore, and niobite.

[0003] FeNb2S4 is a promising electrocatalyst for the electrocatalytic nitrogen reduction to ammonia (NRR). As a typical two-dimensional transition metal sulfide, FeNb2S4 exhibits excellent nitrogen adsorption energy and low reaction overpotential due to its unique [FeS6]-[NbS6] alternating layered structure and exposed metal active sites, making it a highly valuable NRR electrocatalyst material. Currently, there are two processes for preparing FeNb2S4: (1) preparing Nb2Fe alloy by combining niobium powder and carbonyl iron powder, and then obtaining FeNb2S4 by sulfidation; (2) preparing FeNb2S4 in one step by adding a reducing agent and a sulfiding agent using Nb2O5 as raw material. However, the above methods are complex to operate, and the requirements for equipment and production costs are relatively high.

[0004] Therefore, based on the occurrence state of niobium in minerals, developing a simple and low-cost production method for FeNb2S4 has considerable market prospects and economic benefits. Summary of the Invention

[0005] This invention provides a method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4, thereby solving the technical problems of complex operation and high cost in existing FeNb2S4 production methods.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 includes the following steps: (1) Mix a variety of typical niobium minerals with a sulfiding agent, a reducing agent and a fluorine-containing modifier to obtain a mixture; the variety of typical niobium minerals include at least two of columbite, calcite, pyrochlore and niobium calcium ore; the sulfiding agent is an iron-containing sulfiding agent; (2) The mixture is reacted at 1050~1350℃ under a protective atmosphere until complete to obtain a product containing FeNb2S4.

[0008] The reaction principle of the above technical solution is as follows: ; .

[0009] As a further preferred embodiment of the above technical solution, in step (1), the mass ratio of the various typical niobium minerals to the sulfiding agent, reducing agent and modifier is 1:(1~3):(0.2~0.8):(0.01~0.05), and the various typical niobium minerals can be arbitrarily proportioned.

[0010] As a further preferred embodiment of the above technical solution, the sulfiding agent includes at least one of pyrite, pyrrhotite, ferrous disulfide, ferrous sulfide, ferric trisulfide, and pyrrhotite.

[0011] As a further preferred embodiment of the above technical solution, the reducing agent includes at least one of coke powder, coke, charcoal, anthracite, bituminous coal, peat, middlings, graphite, and biomass.

[0012] As a further preferred embodiment of the above technical solution, the modifier includes at least one of NaF, CaF2, KF, and Na3AlF6. The inventors discovered that certain silicate gangues exist in minerals. These silicate gangues possess the ability to form a silicon-oxygen network structure, exhibiting strong structural strength. This results in poor overall fluidity of the reaction system, leading to higher conversion temperatures and thus affecting the efficiency of the conversion reaction. This invention addresses this by adding a fluorine-containing additive, which, during the reaction process, […]. - Ions have a strong ability to disrupt the silicon-oxygen network structure, breaking long Si-O-Si chains to form shorter Si-F bonds or [SiF6]. 2- The formation of complexed ions significantly reduces the structural strength and flow resistance of the slag, while accelerating the internal mass transfer rate (diffusion of ions and molecules). Simultaneously, the low viscosity of the slag allows Nb to... 3+ Fe 2+ With S 2- Better contact. Therefore, at the same temperature, the addition of fluorine-containing modifiers can effectively improve the conversion rate of synergistic transformation of multiple niobium minerals.

[0013] As a further preferred embodiment of the above technical solution, in step (1), the mixture is made into pellets, blocks or granules and then used in step (2).

[0014] As a further preferred embodiment of the above technical solution, in step (2), the reaction time of the mixture is greater than or equal to 30 min.

[0015] As a further preferred embodiment of the above technical solution, in step (2), the protective atmosphere is nitrogen or argon.

[0016] The present invention has the following beneficial effects: This invention systematically solves the core problems of "expensive raw materials, complex processes, and high costs" in the existing FeNb2S4 preparation through mineral synergistic conversion. The mineral raw materials are widely available, which is in line with the short-process conversion of niobium resources "from ore to material", reducing tailings discharge and resource waste. The process route is simple and suitable for large-scale production. It is expected to reduce production costs by about 40% compared with existing methods, with outstanding market prospects and economic benefits. At the same time, the mineral ratio can be flexibly adjusted according to the niobium mineral composition of different mining areas, compatible with multiple raw material combinations, and adaptable to the efficient utilization of ores of different qualities. This enhances the process's adaptability to resource diversity and achieves multiple technical effects such as significant reduction in production costs, simplified operation, and improved resource utilization. It provides an economically feasible new path for the industrial production of niobium-based electrocatalysts. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is an SEM image of the conversion product of Example 1; Figure 3 The XRD pattern of the conversion product of Example 1; Figure 4 The energy spectrum of the FeNb2S4 phase of the conversion product of Example 1; Figure 5 The energy spectrum of the FeS phase of the conversion product of Example 1; Figure 6 The energy spectrum of the cerium-containing phase of the conversion product of Example 1 is shown. Figure 7 This is an SEM image of the conversion product of Example 2; Figure 8 This is an SEM image of the conversion product of Example 3; Figure 9 SEM image of the conversion product of Comparative Example 1; Figure 10 Energy spectrum of the FeNb2S4 phase of the conversion product of Comparative Example 1; Figure 11 The energy spectrum of the FeS phase of the conversion product of Comparative Example 1 is shown. Figure 12 The image shows the energy spectrum of the unreacted phase of the conversion product of Comparative Example 1. Detailed Implementation

[0018] The present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0019] Example 1: like Figure 1As shown, the method for the synergistic conversion of various typical niobium minerals into FeNb2S4 in this embodiment includes the following steps: (1) Take 5g of a mixture of easily calcified ore and columbite (mass ratio 1:1), add 10g of pyrite, 0.05g of sodium fluoride and 2g of coke, and mix thoroughly to obtain a mixture. (2) The mixture was placed directly in a tube furnace and reacted at 1350°C for 30 min in an argon atmosphere. After cooling with the furnace, the conversion product was obtained. The SEM and XRD patterns of the conversion product are shown below. Figure 2 and Figure 3 As shown, the niobium-containing phase is FeNb₂S₄. The energy dispersive spectroscopy (EDS) spectra of the FeNb₂S₄ phase, the FeS phase, and the cerium-containing phase are shown below. Figure 4-6 As shown, the conversion rate of various typical niobium minerals to FeNb2S4 is 97.24%.

[0020] Example 2: like Figure 1 As shown, the method for the synergistic conversion of various typical niobium minerals into FeNb2S4 in this embodiment includes the following steps: (1) Take 5g of a mixture of calcite, columbite and pyrochlore (mass ratio 1:1:1), add 10g of pyrrhotite, 0.25g of calcium fluoride and 2g of coke, mix thoroughly and then press into tablets using a press and a mold to obtain the mixture. (2) The mixture was placed directly in a tube furnace and reacted at 1050°C for 60 min in an argon atmosphere. After cooling with the furnace, the conversion product was obtained. The SEM image of the conversion product is shown below. Figure 7 As shown, the niobium-bearing phase is FeNb2S4, and the conversion rate of various typical niobium minerals to FeNb2S4 is 92.21%.

[0021] Example 3: like Figure 1 As shown, the method for the synergistic conversion of various typical niobium minerals into FeNb2S4 in this embodiment includes the following steps: (1) Take 5g of a mixture of calcite, columbite, pyrochlore and niobium calcium ore (mass ratio 1:1:1), add 12g of pyrite, 0.15g of sodium fluoride and 2g of coke, and mix thoroughly to obtain a mixture. (2) The mixture was placed directly in a tube furnace and reacted at 1200°C for 50 min in an argon atmosphere. After cooling with the furnace, the conversion product was obtained. The SEM image of the conversion product is shown below. Figure 8 As shown, the niobium-bearing phase is FeNb2S4, and the conversion rate of various typical niobium minerals to FeNb2S4 is 96.18%.

[0022] Comparative Example 1: The difference from the example is that sodium fluoride was not added; all other conditions were the same as in Example 1. The SEM image of the conversion product is shown below. Figure 9 As shown, the energy dispersive spectroscopy (EDS) spectra of the FeNb₂S₄ phase, FeS phase, and unreacted phase are respectively as follows: Figure 10-12 As shown, the conversion rate to FeNb2S4 was 53.64%.

[0023] Comparative Example 2: The difference from the example is that calcium fluoride was not added; all other conditions were the same as in Example 2. The conversion rate to FeNb2S4 was 40.93%.

[0024] Comparative Example 3: The difference from the example is that sodium fluoride was not added; all other conditions were the same as in Example 3. The conversion rate to FeNb2S4 was 58.15%.

[0025] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

[0026] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4, characterized in that, Includes the following steps: (1) Mix a variety of typical niobium minerals with a sulfiding agent, a reducing agent and a fluorine-containing modifier to obtain a mixture; the variety of typical niobium minerals include at least two of columbite, calcite, pyrochlore and niobium calcium ore; the sulfiding agent is an iron-containing sulfiding agent; (2) The mixture is reacted at 1050~1350℃ under a protective atmosphere until complete to obtain a product containing FeNb2S4.

2. The method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 according to claim 1, characterized in that, In step (1), the mass ratio of the various typical niobium minerals to the sulfiding agent, reducing agent and modifier is 1: (1~3): (0.2~0.8): (0.01~0.05).

3. The method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 according to claim 1, characterized in that, The sulfiding agent includes at least one of pyrite, pyrrhotite, ferrous disulfide, ferrous sulfide, ferric trisulfide, and pyrrhotite.

4. The method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 according to claim 1, characterized in that, The reducing agent includes at least one of coke powder, coke, charcoal, anthracite, bituminous coal, peat, middlings, graphite, and biomass.

5. The method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 according to claim 1, characterized in that, The modifier includes at least one of NaF, CaF2, KF, and Na3AlF6.

6. The method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 according to any one of claims 1-5, characterized in that, In step (1), the mixture is formed into pellets, blocks or granules before being used in step (2).

7. The method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 according to any one of claims 1-5, characterized in that, In step (2), the reaction time of the mixture is greater than or equal to 30 min.

8. The method for the synergistic conversion of multiple typical niobium minerals into FeNb2S4 according to any one of claims 1-5, characterized in that, In step (2), the protective atmosphere is nitrogen or argon.

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