A method for preparing flaky nano-tungsten oxide

Abstract

The present invention belongs to the technical field of tungsten smelting, and specifically relates to a method for preparing flaky nano-tungsten oxide. The method comprises the following steps: adding a reserved tungstate solution to reserved hydrochloric acid by dropwise addition, adding sulfuric acid dropwise while adding the hydrochloric acid, and stirring. After the dropwise addition is completed, the solution is filtered and washed. The tungstic acid after filtration and washing is roasted and sieved to obtain flaky nano-tungsten oxide. By adding a control substance in the dropwise addition step of the preparation process and precisely controlling the added amount, not only can the purity of the obtained product reach a high-purity standard, but flaky nano-tungsten oxide with controllable morphology can also be prepared, and the industrialization prospect is broad.

Description

Technical Field

[0001] The invention belongs to the technical field of tungsten smelting, and in particular relates to a method for preparing disk-shaped nano tungsten oxide. Background Art

[0002] Tungsten is a strategic resource, a plentiful element and a protected mineral in my country. As a major exporter, accelerating the research and development of tungsten materials and transforming tungsten products from primary to high-tech, high-value-added products is imperative. Therefore, research into the preparation technology of high-performance tungsten materials is of great practical significance.

[0003] With the advent of nanotechnology, nano-tungsten oxide has broad application prospects. Recent research indicates that compared to conventional tungsten oxide, nano-tungsten oxide offers two advantages: 1. A larger surface area provides more reactive surfaces for physical and chemical reactions; 2. The quantum confinement effect caused by its small particle size significantly impacts charge transport and optical properties. Material performance depends not only on particle size and surface area, but also on the micromorphology of the material. The controllable morphology of nanomaterials plays an indelible role in the research and development of their properties. Therefore, developing a method for producing nano-tungsten oxide with controllable morphology is particularly important. Summary of the Invention

[0004] To address the problems of the prior art, the main purpose of the present invention is to propose a method for preparing flaky nano-tungsten oxide. By adding a control substance during the dropwise addition step of the preparation process and precisely controlling the amount of addition, not only can the purity of the obtained product reach high-purity standards, but flaky nano-tungsten oxide can also be prepared with controllable morphology, which has broad prospects for industrialization.

[0005] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0006] A method for preparing flaky nano-tungsten oxide comprises the following steps:

[0007] S1. Prepare tungstate solution for later use;

[0008] S2. Prepare hydrochloric acid, the volume of which is 1.2 to 2.0 times the volume of the tungstate solution;

[0009] S3. Prepare sulfuric acid, the volume of which is 1 / 10 to 1 / 5 of the volume of hydrochloric acid;

[0010] S4. The spare tungstate solution was added dropwise to the spare hydrochloric acid, and sulfuric acid was added dropwise while the hydrochloric acid was added, and stirred;

[0011] S5. After the addition is complete, filter and wash;

[0012] S6. The filtered and washed tungstic acid is calcined at 550-850°C and sieved to obtain flaky nano-tungsten oxide.

[0013] As a preferred embodiment of the method for preparing flaky nano-tungsten oxide according to the present invention, in step S1, the tungstate solution has a concentration of 200 to 300 g / L in terms of tungsten trioxide.

[0014] As a preferred embodiment of the method for preparing flaky nano-tungsten oxide according to the present invention, in step S2, the concentration of the hydrochloric acid is 15-36 wt%.

[0015] As a preferred embodiment of the method for preparing flaky nano-tungsten oxide according to the present invention, in step S3, the concentration of sulfuric acid is 16-18 mol / L.

[0016] As a preferred embodiment of the method for preparing flaky nano-tungsten oxide according to the present invention, in step S4, the dropping time is 1 to 2 hours.

[0017] As a preferred embodiment of the method for preparing flaky nano-tungsten oxide according to the present invention, in step S4, the tungstate solution is added dropwise through a separatory funnel.

[0018] As a preferred embodiment of the method for preparing flaky nano-tungsten oxide described in the present invention, in step S4, sulfuric acid is placed in a container, compressed air is filled into the container to generate a certain pressure, and sulfuric acid is added dropwise through a pneumatic regulating valve.

[0019] As a preferred embodiment of the method for preparing flaky nano-tungsten oxide according to the present invention, in step S6, the calcination time is 2 to 4 hours, and the sieve used for sieving is 120 to 160 meshes.

[0020] A disc-shaped nano-tungsten oxide is prepared by using the above-mentioned method for preparing disc-shaped nano-tungsten oxide.

[0021] The beneficial effects of the present invention are as follows:

[0022] The present invention provides a method for preparing flaky nano-tungsten oxide. The method comprises the following steps: adding a reserved tungstate solution to a reserved hydrochloric acid solution by dropwise addition; adding sulfuric acid dropwise while adding the hydrochloric acid and stirring; filtering and washing the solution after the dropwise addition; calcining the filtered and washed tungstic acid, and sieving the solution to obtain flaky nano-tungsten oxide. By adding a control substance in the dropwise addition step of the preparation process and precisely controlling the amount of the substance added, not only can the purity of the obtained product reach a high-purity standard, but flaky nano-tungsten oxide with controllable morphology can also be prepared, which has broad prospects for industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 This is an SEM image of the disc-shaped nano-tungsten oxide prepared in Example 1 of the present invention;

[0025] Figure 2 This is an SEM image of the disc-shaped nano-tungsten oxide prepared in Example 2 of the present invention;

[0026] Figure 3 This is a SEM image of nano-tungsten oxide prepared in Comparative Example 1 of the present invention;

[0027] Figure 4 This is the SEM image of nano-tungsten oxide prepared in Comparative Example 2 of the present invention.

[0028] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0029] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0030] The main purpose of the present invention is to propose a method for preparing flaky nano-tungsten oxide. By adding a control substance during the dropwise addition step of the preparation process and precisely controlling the added amount, not only can the purity of the obtained product reach high-purity standards, but flaky nano-tungsten oxide can also be prepared with controllable morphology, which has broad prospects for industrialization.

[0031] According to one aspect of the present invention, the present invention provides the following technical solutions:

[0032] A method for preparing flaky nano-tungsten oxide comprises the following steps:

[0033] S1. Prepare tungstate solution for later use;

[0034] S2. Prepare hydrochloric acid, the volume of which is 1.2 to 2.0 times the volume of the tungstate solution;

[0035] S3. Prepare sulfuric acid, the volume of which is 1 / 10 to 1 / 5 of the volume of hydrochloric acid;

[0036] S4. The spare tungstate solution was added dropwise to the spare hydrochloric acid, and sulfuric acid was added dropwise while the hydrochloric acid was added, and stirred;

[0037] S5. After the addition is complete, filter and wash;

[0038] S6. The filtered and washed tungstic acid is calcined at 550-850°C and sieved to obtain flaky nano-tungsten oxide.

[0039] Preferably, in step S1, the tungstate solution has a concentration of 200 to 300 g / L, calculated as tungsten trioxide. Specifically, the concentration, calculated as tungsten trioxide, can be, for example but not limited to, any one of 200 g / L, 210 g / L, 220 g / L, 230 g / L, 240 g / L, 250 g / L, 260 g / L, 270 g / L, 280 g / L, 290 g / L, and 300 g / L, or a range between any two thereof;

[0040] Preferably, in step S2, the concentration of the hydrochloric acid is 15-36 wt%. Specifically, the concentration of the hydrochloric acid can be, for example, but not limited to, any one of 15 wt%, 18 wt%, 21 wt%, 24 wt%, 27 wt%, 30 wt%, 33 wt%, 36 wt%, or a range between any two thereof; the volume of the hydrochloric acid can be, for example, but not limited to, any one of 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times the volume of the tungstate solution, or a range between any two thereof;

[0041] Preferably, in step S3, the concentration of the sulfuric acid is 16-18 mol / L. Specifically, the concentration of the sulfuric acid can be, for example but not limited to, any one of 16 mol / L, 16.5 mol / L, 17 mol / L, 17.5 mol / L, 18 mol / L, or a range between any two thereof; the volume of the sulfuric acid can be, for example but not limited to, any one of 1 / 10, 1 / 8, 3 / 20, 7 / 40, 1 / 5, or a range between any two thereof of the volume of the hydrochloric acid;

[0042] Preferably, in step S4, the dropping time is 1 to 2 hours. The dropping time can be, for example but not limited to, any one of 1 hour, 1.25 hours, 1.5 hours, 1.75 hours, 2 hours, or a range between any two of them;

[0043] Preferably, in step S4, the tungstate solution is added dropwise through a separatory funnel;

[0044] Preferably, in step S4, sulfuric acid is placed in a container, compressed air is introduced into the container to generate a certain pressure, and sulfuric acid is added dropwise through a pneumatic regulating valve. Further preferably, the pressure is 0.5 to 2.0 MPa. Specifically, the pressure can be, for example but not limited to, any one of 0.5 MPa, 1.0 MPa, 1.5 MPa, 2.0 MPa, or a range between any two of the following:

[0045] Preferably, in step S6, specifically, the roasting temperature can be, for example, but not limited to, any one of 550° C., 600° C., 650° C., 700° C., 750° C., 800° C., 850° C., or a range between any two thereof; the roasting time is 2 to 4 hours, and the sieving is performed using a 120-160 mesh sieve; specifically, the roasting temperature can be, for example, but not limited to, any one of 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, or a range between any two thereof;

[0046] A disc-shaped nano-tungsten oxide is prepared by using the above-mentioned method for preparing disc-shaped nano-tungsten oxide.

[0047] The technical solution of the present invention is further described below with reference to specific embodiments.

[0048] Example 1

[0049] A method for preparing flaky nano-tungsten oxide comprises the following steps:

[0050] S1. Prepare a tungstate solution for later use; the tungstate solution is a solution with a concentration of 250 g / L in terms of tungsten trioxide;

[0051] S2. Prepare hydrochloric acid, the volume of which is 2.0 times the volume of the tungstate solution; the concentration of hydrochloric acid is 30wt%;

[0052] S3. Take sulfuric acid as a standby, the volume of sulfuric acid is 1 / 10 of the volume of hydrochloric acid; the concentration of sulfuric acid is 18mol / L;

[0053] S4. The standby tungstate solution is added dropwise to the standby hydrochloric acid, the standby tungstate is placed in a separatory funnel, sulfuric acid is placed in a container, and compressed air is filled into the container to generate a pressure of 0.5 MPa. Sulfuric acid is added dropwise through a pneumatic regulating valve, and stirring is performed during the addition process; the addition time is 1 h;

[0054] S5. After the addition is complete, filter and wash;

[0055] S6. The filtered and washed tungstic acid was calcined at 700°C for 3h and passed through a 120-mesh sieve to obtain a disc-shaped nano-tungsten oxide. Figure 1 shown.

[0056] Example 2

[0057] A method for preparing flaky nano-tungsten oxide comprises the following steps:

[0058] S1. Prepare a tungstate solution for standby use; the tungstate solution is a solution having a concentration of 300 g / L in terms of tungsten trioxide;

[0059] S2. Prepare hydrochloric acid, the volume of which is 1.5 times the volume of the tungstate solution; the concentration of hydrochloric acid is 15wt%;

[0060] S3. Take sulfuric acid as a spare, the volume of sulfuric acid is 1 / 5 of the volume of hydrochloric acid; the concentration of sulfuric acid is 16mol / L;

[0061] S4. Place the spare tungstate in a separatory funnel, add the spare tungstate solution dropwise to the spare hydrochloric acid, place sulfuric acid in a container, and fill the container with compressed air to generate a pressure of 2.0 MPa. Add sulfuric acid dropwise through a pneumatic regulating valve, stirring during the addition process; the addition time is 2 h;

[0062] S5. After the addition is complete, filter and wash;

[0063] S6. The filtered and washed tungstic acid was calcined at 850°C for 2h and passed through a 160-mesh sieve to obtain a disk-shaped nano-tungsten oxide, such as Figure 2 shown.

[0064] Example 3

[0065] A method for preparing flaky nano-tungsten oxide comprises the following steps:

[0066] S1. Prepare a tungstate solution for standby use; the tungstate solution is a solution with a concentration of 200 g / L in terms of tungsten trioxide;

[0067] S2. Prepare hydrochloric acid, the volume of which is 1.2 times the volume of the tungstate solution; the concentration of hydrochloric acid is 36wt%;

[0068] S3. Take sulfuric acid as a spare, the volume of sulfuric acid is 1 / 5 of the volume of hydrochloric acid; the concentration of sulfuric acid is 17mol / L;

[0069] S4. The spare tungstate is placed in a separatory funnel, the spare tungstate solution is added dropwise to the spare hydrochloric acid, sulfuric acid is placed in a container, and compressed air is filled into the container to generate a pressure of 1.0 MPa, sulfuric acid is added dropwise through a pneumatic regulating valve in coordination with stirring during the addition process; the addition time is 1.5 h;

[0070] S5. After the addition is complete, filter and wash;

[0071] S6. The filtered and washed tungstic acid was calcined at 550°C for 4 hours and passed through a 120-mesh sieve to obtain flaky nano-tungsten oxide.

[0072] Comparative Example 1

[0073] A method for preparing nano tungsten oxide comprises the following steps:

[0074] S1. Prepare a tungstate solution for later use; the tungstate solution is a solution with a concentration of 250 g / L in terms of tungsten trioxide;

[0075] S2. Prepare hydrochloric acid, the volume of which is 2.0 times the volume of the tungstate solution; the concentration of hydrochloric acid is 30wt%;

[0076] S3. Take sulfuric acid as a spare, the volume of sulfuric acid is 1 / 5 of the volume of hydrochloric acid; the concentration of sulfuric acid is 17mol / L;

[0077] S4. The spare tungstate was placed in a separatory funnel, added dropwise to the spare hydrochloric acid, sulfuric acid was added in coordination, and stirred; the addition time was 1h;

[0078] S5. After the addition is complete, filter and wash;

[0079] S6. The filtered and washed tungstic acid was calcined at 700°C for 3h and passed through a 120-mesh sieve to obtain nano tungsten oxide, such as Figure 3 As shown in the figure, the morphology of the prepared nano-tungsten oxide is disordered and the morphology cannot be controlled.

[0080] Comparative Example 2

[0081] A method for preparing nano tungsten oxide comprises the following steps:

[0082] S1. Prepare a tungstate solution for later use; the tungstate solution is a solution with a concentration of 250 g / L in terms of tungsten trioxide;

[0083] S2. Prepare hydrochloric acid, the volume of which is 2.0 times the volume of the tungstate solution; the concentration of hydrochloric acid is 30wt%;

[0084] S3. The spare tungstate was placed in a separatory funnel and added dropwise to the spare hydrochloric acid, and stirred; the addition time was 1h;

[0085] S4. After the addition is completed, filter and wash;

[0086] S5. The filtered and washed tungstic acid was calcined at 700°C for 3h and passed through a 120-mesh sieve to obtain nano tungsten oxide, such as Figure 4 As shown, the morphology of the prepared nano-tungsten oxide cannot be controlled.

[0087] The present invention adds a reserved tungstate solution to a reserved hydrochloric acid by dropwise addition, adds sulfuric acid dropwise while adding the hydrochloric acid, and stirs. After the dropwise addition is completed, the solution is filtered and washed. The filtered and washed tungstic acid is roasted and sieved to obtain flaky nano-tungsten oxide. By adding a control substance in the dropwise addition step of the preparation process and accurately controlling the added amount, not only can the purity of the obtained product reach a high-purity standard, but flaky nano-tungsten oxide with controllable morphology can also be prepared, and the industrialization prospect is broad.

[0088] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing flaky nano-tungsten oxide, characterized in that: The steps include: S1. Prepare a tungstate solution for later use; the tungstate solution is a solution with a concentration of 200-300 g / L in terms of tungsten trioxide; S2. Prepare hydrochloric acid, wherein the concentration of the hydrochloric acid is 16 to 36 wt %, and the volume of the hydrochloric acid is 1.2 to 2.0 times the volume of the tungstate solution; S3. Take sulfuric acid for use, the concentration of the sulfuric acid is 15~18mol / L, the volume of sulfuric acid is 1 / 10~1 / 5 of the volume of hydrochloric acid; S4. The standby tungstate solution is added dropwise to the standby hydrochloric acid, and sulfuric acid is added dropwise while the hydrochloric acid is added, and stirred; the addition time is 1 to 2 hours; the sulfuric acid is placed in a container, and compressed air is filled into the container to generate a pressure of 0.5 to 2.0 MPa, and sulfuric acid is added dropwise in coordination with the pneumatic control valve; S5. After the addition is complete, filter and wash; S6. The filtered and washed tungstic acid is calcined at 550-850°C and sieved to obtain flaky nano-tungsten oxide.

2. The method for preparing flaky nano-tungsten oxide according to claim 1, wherein: In the step S4, the tungstate solution is added dropwise through a separatory funnel.

3. The method for preparing flaky nano-tungsten oxide according to claim 1, wherein: In step S6, the calcination time is 2 to 4 hours.

4. The method for preparing flaky nano-tungsten oxide according to claim 1, wherein: In step S6, a 120-160 mesh sieve is used for sieving.

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