Earlier stage treatment process of raw material powder for preparing induction plasma capacitor level nano tantalum powder

Abstract

The invention relates to a pre-treatment technology of raw material powder used for preparing induction plasma capacitor grade nanometer tantalum powder. The technology comprises the steps as follows: a. tantalum powder with the granularity of 2-10micrometer which is prepared by sodium thermal reduction is used raw material; b. spheroidizing treatment is carried out on the raw material tantalum powder by an induction plasma powder synthesizing system, the technological parameters of the spheroidizing treatment are as follows: medium gas flux is 30 standard liter / min; sheath gas flux is 80-120 standard liter / min of argon and 0-10 standard liter / min of hydrogen; reaction chamber pressure is 50-120Kpa; plasma power is 30-60KW; powder feed rate is 2-15kg / h; cooling gas flux is 300-800 standard liter / min; the relative position of a powder feeder is arranged at the middle part of a plasma area; powder feeding gas flux is 8-20 standard liter / min; c. filtering treatment is that vibration filter is carried out by a 160-220 mesh screen mesh on a screen grader; d. air current grading treatment is that grading treatment is carried out on a cyclone separator, the technological parameters of the g rading treatment are as follows: power feed rate is 2-5kg / h, and the grading gas flux is 300-600 standard liter / min. The invention can carry out the continuous preparation of capacitor grade nanometer and submicron tantalum powder and ensures that the raw material is spherical by spheroidizing, filtering and grading treatment, and the powder with the granularity controlled within 2-5 micrometer takes more than 90 percent of the whole powder; and the invention improves the granularity distribution state, overcomes the aggregation and improves the collection efficiency of the tantalum powder, the utilization rate of energy and material and the electrical property.

Description

technical field [0001] The invention relates to a pre-treatment technology of raw material powder for the preparation of induction plasma capacitor grade nano tantalum powder. Background technique [0002] The invention relates to a process approach and related process parameters adopted in the pre-treatment technology of powder raw materials in the preparation process of induction plasma high specific capacitance capacitor grade tantalum powder. [0003] Tantalum capacitors are widely used in high-end electronic products such as automobiles and hearing aids due to their high capacity, high stability and good service status in harsh environments. As the size of electronic products becomes smaller and smaller, tantalum capacitors are required to develop in the direction of miniaturization and high capacity. Correspondingly, higher requirements are put forward for the specific capacitance of tantalum powder for tantalum capacitors. The capacity is closely related to the parti...

AI Technical Summary

Problems solved by technology

And the induction plasma technology is applied to the process of preparing nano-tantalum powder. The key problem in the preparation of nano-tantalum powder for capacitors is not only to prepare nano-scale capacitor-grade tantalum powder, but also to ensure that the prepared powder has good, Concentrated particle size distribution state prevents powder particle size distribution from wide range, resulting in powder performance degradation

In the powder development process, no matter what combination of plasma nano-powder synthesis process parameters is used, the preparation of capacitor-grade nano-tantalum powder still has the following problems: ① The raw material of tantalum powder that is currently available is tantalum prepared by sodium thermal reduction process Powder, this type of powder has a very wide particle size distribution state, and at the same time, the agglomeration phenomenon is serious. When such tantalum powder is sent into the plasma region, very complicated reactions will occur, such as the fusion and growth of powder agglomerates, different raw material powders The re-evaporation and cooling of particle size powder particles will cause a very complicated particle size distribution state; ②Using high-pressure powder prepared by carbon reduction method as raw material is another way to choose powder raw materials, but due to high-pressure powder With a very large average particle size, the collection rate of the prepared nano-tantalum powder is very low, only less than 10% of the raw material of the tantalum powder, the energy utilization rate and material utilization rate of the preparation process are extremely low, and the technical solution is not feasible; ③The particle size range of the tantalum powder Broad, it will also cause the nano-tantalum powder to be adsorbed on the surface of the micron tantalum powder, and the preparation of the capacitor needs to go through the subsequent high-temperature sintering process. This adsorption state will not only increase the specific capacity of the capacitor, but also increase the impurity content of the tantalum powder. , reducing the electrical properties of the powder

[0006] The key technology for the successful application of the induction plasma nano-powder preparation technology to the capacitor tantalum powder preparation process is the pre-treatment technology of the raw material powder used in the induction plasma preparation technology. At present, there are still the following difficult problems to solve: ① Patented technology of Canada Tekna Corporation Although an ultra-high temperature technology platform is provided, and some technical means can be used to adjust the degree of energy coupling between the powder and the plasma to achieve the refinement and nanometerization of the powder, the purpose of the nano powder preparation technology for capacitors Yes, it is not only necessary to realize the nano-size of the powder, but also to control the particle size distribution of the powder. The particle size control of the nano-powder is the difficulty of the current powder technology, and it is also the bottleneck of the application of the induction plasma nano-powder technology; ②Currently The tantalum powder raw material that can be obtained conveniently is tantalum powder prepared by sodium thermal reduction process. This type of powder has a very wide particle size distribution and serious agglomeration phenomenon. If such tantalum powder is sent into the plasma area, very complicated problems will occur. Reactions, such as the fusion and growth of powder agglomerates, the re-evaporation and cooling of powder particles of different particle sizes in the raw material powder, will result in a very complicated particle size distribution; ③Using high-pressure powder prepared by carbon reduction method as raw material , is another option for powder raw materials, but because the high-pressure powder has a very large average particle size, the collection rate of the prepared nano-tantalum powder is very low, only less than 10% of the raw material of the tantalum powder, and the energy utilization rate of the preparation process, The material utilization rate is extremely low, and the technical solution is not feasible; ④The wide range of tantalum powder particle size will also cause the nano-sized tantalum powder to be adsorbed on the surface of the micro-sized tantalum powder. Improve the specific capacity of the capacitor, but also increase the impurity level of the tantalum powder and reduce the electrical properties of the powder

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