Ningxia Orient Tantalum Industry Co., Ltd.

Wenfeng Shi

Yong Li

Xueqing Chen

Xudong Xi

Guoqi Yang

Zhongxiang Li

Xifang Bao

Zhangong Dong

Xiaoyan Yang

Tao Guo

Wei Wang

The present invention relates to the tantalum powder and the process for preparing the same, and also relates to the electrolytic capacitor anode made of the tantalum powder. More particularly, the present invention relates to the tantalum powder having a BET surface area not more than 0.530 m/g, Fisher mean particle size not less than 3.00 &#x3bc;m. The present invention relates to the process for preparing the tantalum powder, wherein the tantalum powder is prepared through reducing tantalum compound with a reducing agent, wherein the tantalum powder as seed is added during reduction, and said tantalum powder as seed is the tantalum powder that has been milled.

Method for preparing a tantalum powder

The present invention provides a process for preparing a tantalum powder with high specific capacity, which process comprising the steps of, in sequence, (1) a first reduction step: mixing tantalum oxide powder and a first reducing agent powder homogenously, and then carrying out reduction reaction in hydrogen and/or inert gas or vacuum atmosphere to obtain a tantalum suboxides powder; (2) a second reduction step: mixing the tantalum suboxides powder obtained from the step (1), in which impurities have been removed, and a second reducing agent powder homogenously, and then carrying out reduction reaction in hydrogen and/or inert gas or vacuum atmosphere to obtain a tantalum powder having high oxygen content; (3) a third reduction step: mixing the tantalum powder having high oxygen content obtained from the step (2), in which impurities have been removed, with a third reducing agent powder homogenously, and then carrying out reduction reaction in hydrogen and/or inert gas or vacuum atmosphere to obtain a tantalum metal powder suitable for capacitors; wherein after each reduction step, the oxidation product of reducing agent and the residual reducing agent are removed from the reaction product.

Process for preparing tantalum powder for capacitors

The present invention relates to a process for preparing powders of niobium suboxides or niobium, wherein the process comprising: mixing the niobium oxides as raw material with reducing agent, conducting a reaction at a temperature in the range of 600&#x2dc;1300&#xb0; C. in an atmosphere of vacuum or inert gas or hydrogen gas, leaching the reaction product to remove the residual reducing agent and the oxides of the reducing agent and other impurities, heat treating at a temperature of the range of 1000&#x2dc;1600&#xb0; C. in an atmosphere of vacuum or inert gas, and screening to obtain the powders of niobium suboxide or niobium of capacitor grade. According to the present invention, the niobium oxides were directly reduced into capacitor grade niobium suboxides or niobium with reducing agents which can be easily removed by mineral acids, wherein the speed of the reaction can be controlled and the reaction can directly reduce the niobium oxides into capacitor grade niobium suboxides or niobium powder. According to the present invention, the process is simple with high yield and high productivity. The products obtained have good flowability, low impurities, uniform distribution of oxygen, and have good electrical properties.

Process for preparing powder of niobium suboxides or niobium

Growing community of inventors

Shizuishan, China

Wenfeng Shi