GB/T 7731.3-2008Ferrotungsten - Determination of copper content - Bis(cyclohexanone)oxalyldihydrazone photometric method and flame atomic absorption spectrometric method (English PDF)

3.1 Principle

Sample decomposition with hydrofluoric acid and nitric acid, perchloric acid treated white smoke, water soluble salts dissolved, separated after the majority of tungsten, lemon

Acid and ammonium hydroxide to adjust the acidity of the reaction after adding BCO 600nm wavelength measured absorbance, isolated from the calibration curve corresponding

The amount of copper.

3.2 Reagents and materials

Unless otherwise indicated in the analysis using only recognized as analytical grade reagents and distilled water or its equivalent purity water.

3.2.1

hydrofluoric acid, rho1.15g/mL.

3.2.2

perchloric acid, rho1.67g/mL.

3.2.3

nitric acid, 1 + 1.

3.2.4

Ammonium hydroxide, 1 + 1.

3.2.5 iron perchlorate solution

Weigh 0.5g electrolytic iron, placed in 300mL beaker, add 20mL hydrochloric acid (rho1.19g/mL), cover

Table dish, was added dropwise hydrogen peroxide (rho1.10g/mL) and then decomposed excess 5mL, heated and evaporated to a volume of about 5mL, cooled, diluted with 25mL

Hydrochloric acid (10 + 6) to move it to the 200mL separating funnel, add 30mL of methyl isobutyl ketone and shaken for about 1min, standing layer, the lower layer of water

Phase shifted original beaker. Was added to the separatory funnel 10mL water, then add 30mL of methyl isobutyl ketone and shaken for about 1min, standing stratification.

The aqueous phase shift in the original beaker was discarded and the organic phase, was added 10mL of hydrochloric acid (rho1.19g/mL), most of the volatile organic phase was heated in a solution,

Was added 5mL of nitric acid (rho1.42g/mL), 20mL of perchloric acid (rho1.67g/mL), is heated and evaporated to take the white smoke of concentrated perchloric acid, and heating was continued for about

3min to the clear solution was cooled, diluted with water to 100mL, and mix. This solution 1mL containing about 5mg iron.

3.2.6

citric acid solution, 200g/L.

3.2.7

bicyclic oxalyl two cyclohexanone hydrazone (BCO -) solution, 0.5g/L, 0.25gBCO weighed in a beaker, was added 20mL of methanol and several

Ml of water, with a glass rod side crushed BCO dissolved while heating, cooled to room temperature and transferred to 500mL volumetric flask, dilute to the mark with water, mix […]