A method for producing a low metal impurity metal

Abstract

A low metal impurity metal preparation method comprises the following steps: step 1, drying of chromium formate; step 2, mixing of the chromium formate and electrolytic chromium metal powder and pressing into a sheet; step 3, placing the pressed sheet-shaped compact into a joule heat flash firing mold and performing flash firing; step 4, taking out the product after flash firing and washing with deionized water until the washing liquid is clear to obtain a metal powder solid, and drying the metal powder solid. The present application uses a metal organic salt (chromium formate) with a purity of greater than or equal to 99.5% as a raw material, introduces high-purity metal seeds to induce directional nucleation, and realizes super-fast temperature rising pyrolysis reduction through joule heat flash firing, significantly reducing the introduction of exogenous metal impurities and internal impurity enrichment, and obtaining high-purity low-impurity metal powder.

Description

Technical Field

[0001] This invention relates to the field of metal material preparation and purification technology, and in particular to a method for preparing metals with low metal impurities. Background Technology

[0002] High-purity metallic materials have important applications in semiconductors, vacuum electronics, and corrosion-resistant alloys, requiring extremely low levels of metallic impurities, typically below the ppm level. Existing preparation processes, such as electrolysis and hydrogen reduction, generally suffer from complex procedures, introduce numerous impurity metals, and consume high energy, making it difficult to produce ultra-high-purity metallic products economically and efficiently.

[0003] Metal-organic salt precursors such as chromium formate have low decomposition temperatures and controllable reaction pathways, but traditional pyrolysis has defects such as slow heating, impurity enrichment and grain disorder, resulting in high metal impurity content in the product. Summary of the Invention

[0004] This invention provides a method for preparing metals with low metal impurities, which overcomes the shortcomings of the prior art, significantly reduces the introduction of exogenous metal impurities and the enrichment of internal impurities, and obtains high-purity, low-impurity metal powder.

[0005] In order to achieve the objectives of this invention, the following technologies are proposed: A method for preparing a metal with low metal impurities, comprising the following steps: Step 1, drying of chromium formate; Step 2: Chromium formate and electrolytic chromium metal powder are mixed and pressed into sheets; Step 3: Place the pressed sheet blank in a Joule heat flash calcination mold and flash calcinate it; Step 4: Remove the product after flash burning and wash it with deionized water until the washing solution is clear to obtain a solid metal powder, and then dry the solid metal powder.

[0006] Furthermore, the purity of chromium formate is ≥99.5%.

[0007] Furthermore, when drying chromium formate, it is dried at 120°C with forced air for 30 minutes, and then cooled to room temperature.

[0008] Furthermore, the amount of electrolytic chromium metal powder added is 1.5 wt%.

[0009] Furthermore, during flash burning, the temperature is increased to 1200°C at a rate of 200°C to 500°C / s under 10⁻¹ Pa, and held for 10 to 30 seconds.

[0010] Furthermore, the obtained metal powder is dried in a vacuum environment at 75°C.

[0011] Furthermore, the total impurity content of the dried metal powder is ≤0.03%, and the yield is ≥90%.

[0012] The advantages of the above technical solution are: This invention uses organometallic salts (chromium formate) with a purity of ≥99.5% as raw materials, introduces high-purity metal seeds to induce directional nucleation, and achieves ultra-fast heating and pyrolysis reduction through Joule thermal flash calcination, which significantly reduces the introduction of exogenous metal impurities and the enrichment of internal impurities, thereby obtaining high-purity, low-impurity metal powder. Attached Figure Description

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will now be described in further detail with reference to the accompanying drawings.

[0014] Figure 1 A finished product image of the pressed sheet compact is shown.

[0015] Figure 2 A picture of the finished product after drying the metal powder is shown. Detailed Implementation

[0016] Example 1 Weigh 5 g of chromium formate powder, add 1.5 wt% (0.075 g) of electrolytic chromium powder with a purity of 99.9%, mix and compress into tablets, then subject to Joule heat flash calcination, heating to 1000℃ at 250 ℃ / s and holding for 15 seconds. The theoretical chromium content is 1.4649 g, and the actual chromium content in the product is approximately 1.318 g, with a yield of approximately 90%. The elemental composition of the obtained metal powder is: Cr ≥96.5%, Fe 0.02%, Si 0.01%, Al 0.005%, O 1.1265%, C 1.2205%.

[0017] Example 2 8 g of chromium formate powder was weighed and added to 1.5 wt% (0.12 g) of electrolytic chromium powder with a purity of 99.9%. The mixture was then pressed into a tablet and subjected to Joule heat flash calcination, with the temperature increased from 500 ℃ / s to 1250 ℃ and held for 20 seconds. The theoretical chromium content was 2.3439 g, and the actual chromium content in the product was approximately 2.109 g, with a yield of approximately 90%. The elemental composition of the obtained metal powder was: Cr ≥ 97.3%, Fe 0.005%, Si 0.008%, Al 0.003%, O 0.7225%, C 0.8525%. The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method for preparing a metal with low metal impurities, characterized in that, Including the following steps: Step 1, drying of chromium formate; Step 2: Chromium formate and electrolytic chromium metal powder are mixed and pressed into sheets; Step 3: Place the pressed sheet blank in a Joule heat flash calcination mold and flash calcinate it; Step 4: Remove the product after flash burning and wash it with deionized water until the washing solution is clear to obtain a solid metal powder, and then dry the solid metal powder.

2. The method for preparing low-metallic-impurity metals according to claim 1, characterized in that, The purity of chromium formate is ≥99.5%.

3. The method for preparing low-metallic-impurity metals according to claim 1, characterized in that, When drying chromium formate, it is dried at 120°C with a forced air for 30 minutes, and then the chromium formate is cooled to room temperature.

4. The method for preparing a low-metallic-impurity metal according to claim 1, characterized in that, The amount of electrolytic chromium metal powder added is 1.5 wt%.

5. The method for preparing a low-metallic-impurity metal according to claim 1, characterized in that, During flash burning, the temperature is increased to 1200℃ at a heating rate of 200℃ to 500℃ / s under 10⁻¹ Pa, and held for 10 to 30 seconds.

6. The method for preparing a low-metallic-impurity metal according to claim 1, characterized in that, The obtained metal powder is dried in a vacuum environment at 75°C.

7. The method for preparing a low-metallic-impurity metal according to claim 1, characterized in that, The total impurity content of the dried metal powder is ≤0.03%, and the yield is ≥90%.

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