Ningxia Orient Tantalum Industry Co., Ltd.

Luntao Pan

Jilin He

Yuewei Cheng

Aiguo Zheng

Yuezhong Ma

Guoqi Yang

Xueqing Zhang

Zhidao Wang

Xuecheng Dong

Bin Li

Baojun Zhu

Hongdong Liu

Chunxiang Wang

Yanping Wang

Shiping Zheng

Xingbang Li

Xiaoli Wen

Ningfeng Yuan

The present invention relates to valve metal particles uniformly containing nitrogen and a method for preparing the same, and a valve metal green pellet and a sintered pellet made from the particles, and an electrolytic capacitor anode. The present invention provides valve metal particles uniformly containing nitrogen, wherein the difference ratio of nitrogen contents of particles is 20% or less. The present invention provides a process for preparing said valve metal particles uniformly containing nitrogen, wherein the raw material particles of the valve metal were heated in a nitrogen-containing gas at a temperature of 200&#xb0; C. or less for 2 hours or more. The present invention also provides a valve metal green pellet made from said valve metal particles. The present invention also provides a valve metal sintered pellet.

Valve metal particles uniformly containing nitrogen and the method for preparing the same, the valve metal green pellets and sintered pellets, and the electrolytic capacitor anodes

A method for spherically granulating and agglomerating metal particles such as tantalum and/or niobium powders is described in the present invention, which includes the steps of: a). comminuting the metal particles to form fine particles having D50 less than 50 &#x3bc;m; b). granulating the comminuted metal particles comprising volatile liquid, for example, tantalum and/or niobium particles comprising volatile liquid, to form wet spherical particles; c). still drying the wet spherical particles and removing volatile liquid to form flowable pre-agglomerated particles with increased bulk density; d). heat treating the pre-agglomerated particles; e). screening the heat treated powder to obtain the flowable agglomerated particles. The present invention provides a flowable spherical agglomerated metal particles, and especially tantalum and/or niobium particles having improved properties. The present agglomerated tantalum powder have a flow rate of at least about 2.0 g/sec, a BET surface area of from about 0.2 to about 6.0 m/g, a FSSS of at least 1.0 &#x3bc;m, a Scott bulk density of from about 1.2 g/cmto about 5.5 g/cm. The present agglomerated niobium powder have a flow rate of at least about 1.0 g/sec, a BET surface area of from about 0.5 to about 8.0 m/g, a FSSS of at least 1.0 &#x3bc;m, a Scott bulk density of from about 0.7 g/cmto about 3.5 g/cm. Said tantalum and/or niobium metal particles have improved pore size distribution of the sintered anodes and increased pellet crush strength. The present invention further provides an electrolytic capacitor anodes made from the tantalum and/or niobium particles according to the present invention having a capacitance of from about 5,000 &#x3bc;FV/g to about 300,000 &#x3bc;FV/g.

Methods for spherically granulating and agglomerating metal particles, and the metal particles prepared thereby, anodes made from the metal patricles

A process of the production of high surface area tantalum and/or niobium powders via the reduction of the corresponding tantalum and/or niobium oxides is disclosed, wherein the reduction is carried out by reacting the tantalum and/or niobium oxides with at least one metal halide selected form the group consisting of halides of Mg, Ca, Sr, Ba and Ce, and an alkali metal at elevation temperature so as to form the tantalum and/or niobium powders. The process of the present invention has the advantages of: simple operation, the tantalum and/or niobium powders obtained have high surface area, high purity, good flowability, therefore are particularly suitable for manufacturing electrolytic capacitors.

Process for the production of high surface area tantalum and/or niobium powders

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Shizuishan, China

Luntao Pan