Tantalum powder and preparation method therefor

A tantalum powder prepared by a method comprising:

• 1) reducing a tantalum fluoride salt with a reducing agent in a molten diluent to obtain a raw tantalum powder, wherein the raw tantalum powder contains boron in an amount of 30˜300 ppm and has a specific surface area of 5˜13 m2/g;
• 2) granulating the tantalum powder to obtain a pre-agglomerated powder, wherein the pre-agglomerated powder has a bulk density of 1˜1.5 g/cm3;
• wherein granulating comprises:
• mixing raw tantalum powder with water to obtain a powder mixed with water;
• drying the powder mixed with water to obtain a dried powder;
• and crushing and sieving the dried powder, wherein the mesh number of the screen for sieving is 120˜470 mesh, and powder that passes through the screen is pre-agglomerated powder;
• 3) sequentially subjecting the pre-agglomerated powder to one or more of the following steps:
• heat treatment, sieving, oxygen reduction treatment, and nitrogen doping;
• and
• 4) sequentially subjecting the powder obtained in 3) to one or more of the following steps:
• acid washing, water washing, drying and sieving, to obtain a tantalum powder product;
• wherein the tantalum powder product has an oxygen content of from 10000 to 31000 ppm;
• a nitrogen content of from 2000 to 3300 ppm;
• a potassium content of from 10 to 50 ppm;
• a boron content of from 20 to 150 ppm;
• and a phosphorous content of from 200 to 400 ppm;
• wherein the tantalum powder product has a specific surface area of 5˜12 m2/g;
• and the ratio of the boron content of the tantalum powder to the specific surface area of the tantalum powder is from 4˜13, the boron content being measured in units of ppm by weight, and the specific surface area being measured in units of m2/g;
• wherein, more than 85% of the total weight of the tantalum powder product can pass through 170 mesh;
• from 5 to 40% of the total weight of the tantalum powder product can pass through a 400 mesh screen;
• and
• the powder that can pass through 170 mesh but not pass through 400 mesh in the tantalum powder product accounts for 60% to 80% of the total weight of the tantalum powder product.