GB/T 6150.7-2008Methods for chemical analysis of tungsten concentrates - Determination of tantalum content and niobium content - Inductively coupled plasma emission spectrometry and spectrophotometry (English PDF)

3.1

nitrate (rho1.42g/mL), pure class distinctions.

3.2

hydrofluoric acid (rho1.14g/mL), pure class distinctions.

3.3

metatungstate (AMT) .( AMT) >=99.99%.

3.4 tantalum standard stock solution

Weigh 0.1000g pure tantalum [(Ta) >=99.9%], placed in 100mL teflon beaker, add

5mL nitric acid (3.1), 5mL of hydrofluoric acid (3.2), cover sheet pan, over low heat until completely dissolved tantalum, removed, cooled to room temperature, transferred to

100mL plastic volumetric flask, dilute with water to volume, and mix. Store in plastic bottle. This solution 1mL containing 1.0mg tantalum.

3.5 niobium standard stock solution

Weigh 0.1000g pure niobium [(Nb) >=99.9%], placed in 100mL teflon beaker, add

5mL nitric acid (3.1), 5mL of hydrofluoric acid (3.2), cover sheet pan, over low heat until completely dissolved niobium, removed, cooled to room temperature, transferred to

100mL plastic volumetric flask, dilute with water to volume, and mix. Store in plastic bottle. This solution 1mL containing 1.0mg niobium.

3.6

tantalum and niobium mixed standard solution A. Pipette 10.00mL tantalum standard stock solution (3.4), 10.00mL niobium standard stock solution (3.5),

In 100mL plastic flask supplemented with 5mL of hydrofluoric acid (3.2) diluted with water to volume, and mix. Store in plastic bottle. This solution

1mL each containing 100µg and 100µg of tantalum and niobium.

3.7 tantalum and niobium mixed standard solution B

Pipette 10.00mL tantalum and niobium mixed standard solution A (3.6), in 100mL plastic flask, supplemented

5mL of hydrofluoric acid (3.2), diluted with water to volume, and mix. Store in plastic bottle. This solution 1mL containing 10µg respectively, and tantalum

10µg niobium.

5.1

Sample size of less than 0.074mm.

5.2

sample was pretreated at 105 °C ~ 110 °C drying 2h, placed in a desiccator to cool to room temperature.