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Method for preparing cathode block of capacitor-grade powder through fused salt electrolytic oxide

A technology of molten salt electrolysis and oxide, which is applied in the field of metallurgy, can solve the problems of not being able to meet the requirements of capacitor grade powder, not suitable for the production of capacitor grade powder, and not easy to produce metals with low oxygen content, and achieve easy crushing powder treatment, low cost, The effect of less gas impurities

Inactive Publication Date: 2012-07-18
NAT ENG RES CENT FOR SPECIAL METAL MATERIALS OF TANTALUM & NIOBIUM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At the same time, this method will have some impact on the quality of the electrolysis product.
[0006] Capacitor-grade powders against gases such as O 2 , N 2 、H 2 and C have strict requirements, and the cathode prepared by the above method has a high impurity content, which cannot meet the requirements of capacitor grade powder
[0007] Chinese patent 200910104204.9 proposes that the metal oxide raw material is directly placed in a corundum crucible of a certain shape, heated and melted by microwaves, and then cooled to prepare the cathode. The cathode obtained by this method is a solid and dense oxide. During the electrolysis process, the oxidation The migration of oxygen ions inside the product is difficult, it is not easy to obtain metals with low oxygen content, and at the same time the efficiency of electrolysis is reduced. The product is blocky and not suitable for the production of metal powder.
[0008] Obviously, the existing cathode preparation technology is not suitable for producing capacitor-grade powder, so it is very necessary to invent a cathode preparation technology that can produce capacitor-grade powder

Method used

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  • Method for preparing cathode block of capacitor-grade powder through fused salt electrolytic oxide
  • Method for preparing cathode block of capacitor-grade powder through fused salt electrolytic oxide
  • Method for preparing cathode block of capacitor-grade powder through fused salt electrolytic oxide

Examples

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Effect test

Embodiment 1

[0024] Take 15g of high-purity tantalum oxide powder 99.99% and mix it with 1.5g of ammonium carbonate, mold it under 20MP pressing pressure, and put it into a vacuum sintering furnace with a vacuum degree of 3.2X10 -3 Pa, sintered at 250°C for 1 hour, and then sintered at 1250°C for 3 hours to make an electrolytic cathode block. The electrolytic oxide method was used to carry out molten salt electrolysis. After 10 hours of electrolysis, the product after electrolysis was pickled, crushed, followed by subsequent treatment, and analyzed for oxygen content, tantalum powder purity, and specific surface area (Table 1), SEM ( figure 1 ), TEM( figure 2 ). The above-mentioned powder is used for electrical performance testing. 0.10g of tantalum powder is used to press a cylinder with a diameter of Φ3mm, and a tantalum wire is pressed in the middle, which is used as a lead wire for electrical monitoring after sintering. Then sinter at 1200-1300°C for 10min to make a porous sintered ...

Embodiment 2

[0026] Take 10g of high-purity tantalum oxide powder 99.99% and mix it with 0.8g of urea, mold it under 15MP pressing pressure, put it into a vacuum sintering furnace with a vacuum degree of 4.1X10 -3 Pa, sintered at 250°C for 0.5 hours, and then sintered at 1150°C for 5 hours to make an electrolytic cathode block. The electrolytic oxide method was used for molten salt electrolysis. After 8 hours of electrolysis, the electrolyzed product was pickled, crushed, and subsequently processed to analyze oxygen content, tantalum powder purity, and specific surface (see Table 1). The above-mentioned powder is used for electrical performance testing. 0.10g of tantalum powder is used to press a cylinder with a diameter of Φ3mm, and a tantalum wire is pressed in the middle, which is used as a lead wire for electrical monitoring after sintering. Then sinter at 1200-1300°C for 10min to make a porous sintered body, place the sintered body in 0.1 (Wt%)H 3 PO 4 In 16v energization, at 30 (wt...

Embodiment 3

[0030] Take 10g of high-purity tantalum oxide powder 99.9% and mix it with 1.5g of polyvinyl butyral (PVB), mold it under 10MP pressing pressure, put it into a vacuum sintering furnace with a vacuum degree of 8.6X10-4 Pa, and sinter at 350°C for 1 After 4 hours, an electrolytic cathode block was fabricated after sintering at 1150 °C for 4 hours. The electrolytic oxide method is used for molten salt electrolysis. After electrolysis for 10 hours, the product is pickled, and the oxygen content of niobium monoxide is measured and calculated to be 14.9% by oxygen weight gain method. Using the same capacitance detection method as tantalum powder, the specific volume is 105120μF·V / g, and the leakage current is 2.5x10-4μA / μF·V.

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Abstract

The invention relates to a method for preparing a cathode block of capacitor-grade powder through a fused salt electrolytic oxide. A metallic oxide for preparing a capacitor and a pore-forming agent are mixed, formed by pressing and then subjected to low temperature sintering in a vacuum state and high temperature sintering to obtain the cathode block. The method adopts a metallic oxide raw material to be mixed with the pore-forming agent which is resolved easily at low temperature and is not reacted with the oxide, the metallic oxide raw material is formed by pressing and subjected to the low temperature sintering in the vacuum state for a period of time, the pore-forming agent is removed, and then the metallic oxide raw material is subjected to the high temperature sintering to obtain the high-strength and high-electrolytic-efficiency cathode block for electrolysis suitable for preparation of the capacitor-grade powder. The method is simple in process, strong in operability and low in cost, the prepared electrolysis cathode is large in strength and high in porosity, metal powder with low oxygen content can be prepared in the electrolytic process within a short period of time, the electrolytic process is high, and electrolytic products are high in purity, large in specific surface area, few in gaseous impurities and easily treated in a pulverized mode.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a method for preparing a cathode block for preparing capacitor grade powder by electrolyzing oxides from molten salt. Background technique [0002] The process of electrolyzing metal oxides in molten salt to prepare metal and its alloy powder is different from the traditional molten salt electrolysis process. This process was discovered in 1997 by Fray, Farthing and Chen, professors of the University of Cambridge in England, when they were studying how to remove the oxide film on the surface of Ti, so it is also called the FFC Cambridge process. The core of the FFC Cambridge process is to make a solid oxide cathode, and under the conditions of a temperature lower than the melting point of the metal and a molten salt decomposition voltage, the metal oxide is electrolytically reduced, and oxygen ions enter the molten salt and migrate to the anode for discharge. At the cathode t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25C7/02C25C5/04H01G9/042C04B35/495C04B35/622
Inventor 孙本双王东新李军义赵勇
Owner NAT ENG RES CENT FOR SPECIAL METAL MATERIALS OF TANTALUM & NIOBIUM