Preparation method of high-purity platinum powder
By introducing inert gas carbon dioxide during the reduction process and performing ultrasonic treatment, combined with gradient heating calcination, the problem of preparing high-purity platinum powder using traditional methods has been solved, and the preparation of high-purity platinum powder has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI CHANGCHI NEW MATERIAL TECHNOLOGY CO LTD
- Filing Date
- 2026-02-26
- Publication Date
- 2026-05-01
AI Technical Summary
The traditional ammonium chloroplatinate precipitation method is difficult to meet the high purity requirements of modern industry for high-purity platinum powder.
The reduction process involves introducing an inert gas containing carbon dioxide and ultrasonic treatment, combined with gradient heating and calcination, and controlling the pH value of the reduction environment to ensure reaction uniformity and dispersion.
This significantly improves the purity of platinum powder, reaching greater than 99.99%, and avoids the problem of local over-acidity affecting the reduction rate in traditional methods.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of platinum group metal purification technology, specifically to a method for preparing high-purity platinum powder. Background Technology
[0002] High-purity platinum powder, due to its excellent chemical stability, high electrical conductivity, and thermal conductivity, is widely used in semiconductor devices, electronic components, defense, and pharmaceuticals. As the requirements for material purity continue to increase, the traditional ammonium chloroplatinate precipitation method is no longer sufficient to meet the needs of modern industry; therefore, new purification processes need to be developed. Summary of the Invention
[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art and to provide a method for preparing high-purity platinum powder.
[0004] The technical solution of the present invention is as follows: A method for preparing high-purity platinum powder includes the following steps: S1: After filtering and washing the ammonium chloroplatinate precipitate, add deionized water, adjust the pH to 1-3 with acid, and reduce it to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide is introduced, and ultrasound is performed at the same time as the inert gas is introduced. S2: Wash the sponge-like platinum powder repeatedly with pure water at 60-90℃ until no chloride ions remain; S3: The spongy platinum powder treated by S2 is dried under vacuum or inert atmosphere to obtain fine black platinum powder; S4: Fine black platinum powder is calcined by gradient heating to obtain high-purity platinum powder.
[0005] As a preferred embodiment of the present invention, in step S1, the ultrasound is performed in three temperature ranges: a first temperature range of 50-65°C, a second temperature range of 65-70°C, and a third temperature range of 70-85°C; each temperature range is performed for 5-10 minutes, and the ultrasonic frequency is 3-8 kHz.
[0006] As a preferred embodiment of the present invention, the inert gas contains 5-10% carbon dioxide by volume during the first temperature range; The inert gas in the second temperature range contains 10-20% carbon dioxide by volume; The inert gas in the third temperature range contains 20-30% carbon dioxide by volume.
[0007] As a preferred embodiment of the present invention, in step S1, the reducing agent is hydrazine hydrate.
[0008] As a preferred embodiment of the present invention, in step S1, the ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 25-30:1 (ml / g).
[0009] As a preferred embodiment of the present invention, in step S1, the acid solution is hydrochloric acid with a concentration of 0.1-0.3 mol / L.
[0010] As a preferred embodiment of the present invention, in step S1, the mass ratio of ammonium chloroplatinate to reducing agent is 1:0.1-0.5.
[0011] As a preferred embodiment of the present invention, the gradient heating calcination in step S4 is specifically as follows: Initial stage: Increase the temperature to 200-400℃ at a rate of 3-5℃ / min to remove water of crystallization and adsorbates; Intermediate stage: Decompose organic components by increasing the temperature to 500-600℃ at a rate of 7-10℃ / min; Final stage: Metallization is completed by increasing the temperature to 600-800℃ at a rate of 20-30℃ / min.
[0012] The present invention also discloses a high-purity platinum powder, which is prepared by the preparation method described above.
[0013] As a preferred embodiment of the present invention, the purity of the platinum powder is greater than 99.99%.
[0014] The beneficial effects of this invention are: This invention utilizes an inert gas containing carbon dioxide during the reduction of platinum powder to stably control the pH of the reduction environment, preventing localized over-acidity from affecting the reduction rate. Furthermore, the introduction of the inert gas further homogenizes the reactants, resulting in a more uniform reaction and significantly improving the purity of the platinum powder. Additionally, the combination with ultrasound allows the vibrations to accelerate the mixing and diffusion between the inert gas and carbon dioxide, leading to a more uniform gas composition and better control over the pH of the reduction atmosphere, as well as the dispersion of reactants and products. Moreover, the ultrasound is conducted in multiple temperature ranges. At lower temperatures, the material exhibits fragmented dispersion, while at higher temperatures, molecular motion intensifies, resulting in short-range homogeneous dispersion. Combined with the cavitation effect of ultrasound, this further enhances the dispersion effect. Adjusting the carbon dioxide content at different temperature ranges, combined with the dispersion motion of ultrasound, further improves the control of the pH of the reduction environment, avoiding the problem of localized over-acidity that can occur with traditional strong acid control, thus affecting the reduction process. Detailed Implementation
[0015] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.
[0016] In the following examples, the inert gas is nitrogen.
[0017] Example 1 A method for preparing high-purity platinum powder includes the following steps: S1: After filtering and washing the ammonium chloroplatinate precipitate, deionized water is added, the pH is adjusted to 1.5 with acid, and then it is reduced to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide is introduced, and ultrasound is performed at the same time as the inert gas is introduced. The ultrasound is performed in three temperature ranges: a first temperature range of 55°C, a second temperature range of 70°C, and a third temperature range of 85°C. Each temperature range lasts for 5 minutes, and the ultrasonic frequency is 7 kHz.
[0018] In the first temperature range, the inert gas contains 8% carbon dioxide by volume. The inert gas in the second temperature range contains 15% carbon dioxide by volume. The inert gas in the third temperature range contains 25% carbon dioxide by volume.
[0019] The reducing agent used is hydrazine hydrate.
[0020] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0021] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0022] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0023] S2: Wash the sponge-like platinum powder repeatedly with pure water at 80℃ until no chloride ions remain; S3: The spongy platinum powder treated by S2 is dried under vacuum or inert atmosphere to obtain fine black platinum powder; S4: Fine black platinum powder is calcined by gradient heating to obtain high-purity platinum powder.
[0024] In step S4, the gradient heating calcination is specifically as follows: Initial stage: Increase the temperature to 300℃ at a rate of 4℃ / min and hold for 10min; Intermediate stage: Increase the temperature to 550℃ at a rate of 8℃ / min and hold for 25 minutes; Final stage: Increase the temperature to 800℃ at a rate of 25℃ / min and hold for 30 minutes.
[0025] Example 2 A method for preparing high-purity platinum powder includes the following steps: S1: After filtering and washing the ammonium chloroplatinate precipitate, deionized water is added, the pH is adjusted to 1.5 with acid, and then it is reduced to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide is introduced, and ultrasound is performed at the same time as the inert gas is introduced. The ultrasound is performed in three temperature ranges: a first temperature range of 50°C, a second temperature range of 65°C, and a third temperature range of 80°C. Each temperature range lasts for 6 minutes, and the ultrasonic frequency is 8kHz.
[0026] In the first temperature range, the inert gas contains 8% carbon dioxide by volume. The inert gas in the second temperature range contains 15% carbon dioxide by volume. The inert gas in the third temperature range contains 25% carbon dioxide by volume.
[0027] The reducing agent used is hydrazine hydrate.
[0028] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0029] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0030] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0031] S2: Wash the sponge-like platinum powder repeatedly with pure water at 80℃ until no chloride ions remain; S3: The spongy platinum powder treated by S2 is dried under vacuum or inert atmosphere to obtain fine black platinum powder; S4: Fine black platinum powder is calcined by gradient heating to obtain high-purity platinum powder.
[0032] In step S4, the gradient heating calcination is specifically as follows: Initial stage: Increase the temperature to 300℃ at a rate of 4℃ / min and hold for 10min; Intermediate stage: Increase the temperature to 550℃ at a rate of 8℃ / min and hold for 25 minutes; Final stage: Increase the temperature to 800℃ at a rate of 25℃ / min and hold for 30 minutes.
[0033] Example 3 A method for preparing high-purity platinum powder includes the following steps: S1: After filtering and washing the ammonium chloroplatinate precipitate, deionized water is added, the pH is adjusted to 1.5 with acid, and then it is reduced to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide is introduced, and ultrasound is performed at the same time as the inert gas is introduced. The ultrasound is performed in three temperature ranges: a first temperature range of 55°C, a second temperature range of 70°C, and a third temperature range of 85°C. Each temperature range lasts for 5 minutes, and the ultrasonic frequency is 7 kHz.
[0034] In the first temperature range, the inert gas contains 5% carbon dioxide by volume. The inert gas in the second temperature range contains 20% carbon dioxide by volume. The inert gas in the third temperature range contains 30% carbon dioxide by volume.
[0035] The reducing agent used is hydrazine hydrate.
[0036] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0037] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0038] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0039] S2: Wash the sponge-like platinum powder repeatedly with pure water at 80℃ until no chloride ions remain; S3: The spongy platinum powder treated by S2 is dried under vacuum or inert atmosphere to obtain fine black platinum powder; S4: Fine black platinum powder is calcined by gradient heating to obtain high-purity platinum powder.
[0040] In step S4, the gradient heating calcination is specifically as follows: Initial stage: Increase the temperature to 300℃ at a rate of 4℃ / min and hold for 10min; Intermediate stage: Increase the temperature to 550℃ at a rate of 8℃ / min and hold for 25 minutes; Final stage: Increase the temperature to 800℃ at a rate of 25℃ / min and hold for 30 minutes.
[0041] Example 4 A method for preparing high-purity platinum powder includes the following steps: S1: After filtering and washing the ammonium chloroplatinate precipitate, deionized water is added, the pH is adjusted to 1.5 with acid, and then it is reduced to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide is introduced, and ultrasound is performed at the same time as the inert gas is introduced. The ultrasound is performed in three temperature ranges: a first temperature range of 50°C, a second temperature range of 65°C, and a third temperature range of 80°C. Each temperature range lasts for 6 minutes, and the ultrasonic frequency is 8kHz.
[0042] In the first temperature range, the inert gas contains 8% carbon dioxide by volume. The inert gas in the second temperature range contains 15% carbon dioxide by volume. The inert gas in the third temperature range contains 25% carbon dioxide by volume.
[0043] The reducing agent used is hydrazine hydrate.
[0044] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0045] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0046] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0047] S2: Wash the sponge-like platinum powder repeatedly with pure water at 80℃ until no chloride ions remain; S3: The spongy platinum powder treated by S2 is dried under vacuum or inert atmosphere to obtain fine black platinum powder; S4: Fine black platinum powder is calcined by gradient heating to obtain high-purity platinum powder.
[0048] In step S4, the gradient heating calcination is specifically as follows: Initial stage: Increase the temperature to 300℃ at a rate of 4℃ / min and hold for 10min; Intermediate stage: Increase the temperature to 550℃ at a rate of 8℃ / min and hold for 25 minutes; Final stage: Increase the temperature to 800℃ at a rate of 25℃ / min and hold for 30 minutes.
[0049] Example 5 A method for preparing high-purity platinum powder includes the following steps: S1: After filtering and washing the ammonium chloroplatinate precipitate, deionized water is added, the pH is adjusted to 1.5 with acid, and then it is reduced to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide is introduced, and ultrasound is performed at the same time as the inert gas is introduced. The ultrasound is performed in three temperature ranges: a first temperature range of 55°C, a second temperature range of 70°C, and a third temperature range of 85°C. Each temperature range lasts for 10 minutes, and the ultrasonic frequency is 3 kHz.
[0050] In the first temperature range, the inert gas contains 5% carbon dioxide by volume. The inert gas in the second temperature range contains 10% carbon dioxide by volume. The inert gas in the third temperature range contains 20% carbon dioxide by volume.
[0051] The reducing agent used is hydrazine hydrate.
[0052] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0053] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0054] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0055] S2: Wash the sponge-like platinum powder repeatedly with pure water at 80℃ until no chloride ions remain; S3: The spongy platinum powder treated by S2 is dried under vacuum or inert atmosphere to obtain fine black platinum powder; S4: Fine black platinum powder is calcined by gradient heating to obtain high-purity platinum powder.
[0056] In step S4, the gradient heating calcination is specifically as follows: Initial stage: Increase the temperature to 300℃ at a rate of 4℃ / min and hold for 10min; Intermediate stage: Increase the temperature to 550℃ at a rate of 8℃ / min and hold for 25 minutes; Final stage: Increase the temperature to 800℃ at a rate of 25℃ / min and hold for 30 minutes.
[0057] Comparative Example 1 Unlike Example 1, only carbon dioxide gas is introduced; S1 is as follows: after filtering and washing the ammonium chloroplatinate precipitate, deionized water is added, the pH is adjusted to 1.5 with acid, and then it is reduced to sponge-like platinum powder with a reducing agent. During the reduction process, carbon dioxide gas is introduced and ultrasound is performed at the same time. The ultrasound is performed in three temperature ranges: a first temperature range of 55°C, a second temperature range of 70°C, and a third temperature range of 85°C. Each temperature range lasts for 5 minutes, and the ultrasonic frequency is 7 kHz.
[0058] The reducing agent used is hydrazine hydrate.
[0059] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0060] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0061] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0062] The rest is the same as in Example 1.
[0063] Comparative Example 2 Unlike Example 1, ultrasound was not performed. Specifically, S1 is as follows: S1: After filtering and washing the ammonium chloroplatinate precipitate, deionized water was added, the pH was adjusted to 1.5 with acid, and then it was reduced to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing 25% carbon dioxide gas by volume was introduced.
[0064] The reducing agent used is hydrazine hydrate.
[0065] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0066] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0067] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0068] The rest is the same as in Example 1.
[0069] Comparative Example 3 Unlike Example 1, the ultrasound was performed at the same temperature. Specifically, S1 is as follows: After filtering and washing the ammonium chloroplatinate precipitate, deionized water was added, the pH was adjusted to 1.5 with acid, and then it was reduced to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing 25% carbon dioxide gas by volume was introduced, and ultrasound was performed while the inert gas was introduced. The ultrasound was performed at 65°C for 25 minutes, with an ultrasound frequency of 7 kHz.
[0070] The reducing agent used is hydrazine hydrate.
[0071] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0072] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0073] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0074] The rest is the same as in Example 1.
[0075] Comparative Example 4 Unlike Example 1, the same amount of carbon dioxide was introduced into different temperature ranges of the ultrasound. Specifically, S1 is as follows: After filtering and washing the ammonium chloroplatinate precipitate, deionized water was added, the pH was adjusted to 1.5 with acid, and then it was reduced to spongy platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide was introduced, and ultrasound was performed simultaneously with the introduction of the inert gas. The ultrasound is performed in three temperature ranges: a first temperature range of 55°C, a second temperature range of 70°C, and a third temperature range of 85°C. Each temperature range lasts for 5 minutes, and the ultrasonic frequency is 7 kHz.
[0076] All three inert gases contain 25% carbon dioxide by volume.
[0077] The reducing agent used is hydrazine hydrate.
[0078] The ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 30:1 (ml / g).
[0079] The acid solution is hydrochloric acid with a concentration of 0.1 mol / L.
[0080] The mass ratio of ammonium chloroplatinate to reducing agent is 1:0.3.
[0081] The rest is the same as in Example 1.
[0082] The performance of the samples from the examples and comparative examples was tested, and the test results are shown in Table 1.
[0083] Table 1 Performance test results of the examples and comparative examples
[0084] As can be seen from the table above, the platinum powder of this invention has a high purity, all exceeding 99.99%. The main reason for this is likely that the introduction of an inert gas containing carbon dioxide can stably control the pH of the reduction environment, preventing localized over-acidity from affecting the reduction rate. Furthermore, the introduction of inert gas can further homogenize the reactants, making the reaction more uniform and significantly improving the purity of the platinum powder. Additionally, the combination with ultrasound, where the vibrations of ultrasound may accelerate the mixing and diffusion between the inert gas and carbon dioxide, results in a more uniform gas composition, better regulating the pH of the reduction atmosphere and dispersing the reactants and products. Moreover, the ultrasound is conducted in multiple temperature ranges. At lower temperatures, the material exhibits fragmented dispersion, while at higher temperatures, molecular motion intensifies, resulting in short-range homogeneous dispersion. Combined with the cavitation effect of ultrasound, this leads to even better dispersion. Furthermore, adjusting the carbon dioxide content at different temperature ranges, combined with the dispersive motion of ultrasound, further improves the control of the pH of the reduction environment, avoiding the problem of localized over-acidity that occurs with traditional strong acid control, which affects the reduction process.
[0085] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing high-purity platinum powder, characterized in that, Includes the following steps: S1: After filtering and washing the ammonium chloroplatinate precipitate, add deionized water, adjust the pH to 1-3 with acid, and reduce it to sponge-like platinum powder with a reducing agent. During the reduction process, an inert gas containing carbon dioxide is introduced, and ultrasound is performed at the same time as the inert gas is introduced. S2: Wash the sponge-like platinum powder repeatedly with pure water at 60-90℃ until no chloride ions remain; S3: The spongy platinum powder treated by S2 is dried under vacuum or inert atmosphere to obtain fine black platinum powder; S4: Fine black platinum powder is calcined by gradient heating to obtain high-purity platinum powder.
2. The method for preparing high-purity platinum powder according to claim 1, characterized in that, In step S1, the ultrasound is performed in three temperature ranges: a first temperature range of 50-65℃, a second temperature range of 65-70℃, and a third temperature range of 70-85℃. Each temperature range is performed for 5-10 minutes, and the ultrasound frequency is 3-8kHz.
3. The method for preparing high-purity platinum powder according to claim 2, characterized in that, In the first temperature range, the inert gas contains 5-10% carbon dioxide by volume. The inert gas in the second temperature range contains 10-20% carbon dioxide by volume; The inert gas in the third temperature range contains 20-30% carbon dioxide by volume.
4. The method for preparing high-purity platinum powder according to claim 1, characterized in that, In step S1, the reducing agent is hydrazine hydrate.
5. The method for preparing high-purity platinum powder according to claim 1, characterized in that, In step S1, the ratio of the volume of deionized water to the mass of ammonium chloroplatinate solid is 25-30:1 (ml / g).
6. The method for preparing high-purity platinum powder according to claim 1, characterized in that, In step S1, the acid solution is hydrochloric acid with a concentration of 0.1-0.3 mol / L.
7. The method for preparing high-purity platinum powder according to claim 1, characterized in that, In step S1, the mass ratio of ammonium chloroplatinate to reducing agent is 1:0.1-0.
5.
8. The method for preparing high-purity platinum powder according to claim 1, characterized in that, In step S4, the gradient heating calcination is specifically as follows: Initial stage: Increase the temperature to 200-400℃ at a rate of 3-5℃ / min to remove water of crystallization and adsorbates; Intermediate stage: Decompose organic components by increasing the temperature to 500-600℃ at a rate of 7-10℃ / min; Final stage: Metallization is completed by increasing the temperature to 600-800℃ at a rate of 20-30℃ / min.
9. A high-purity platinum powder, characterized in that, It is prepared by any one of the preparation methods described in claims 1-8.
10. The high-purity platinum powder according to claim 9, characterized in that, The platinum powder has a purity greater than 99.99%.