GB/T 15923-2010Method for chemical analysis of nickel ores - Determination of nickel content (English PDF)

4.5 Hydrofluoric acid (rho

1.13 g/mL). Warning: Hydrofluoric acid is toxic and corrosive, so gloves shall be worn during operation to avoid contact with the skin!

4.6 Perchloric acid (rho

1.67 g/mL). Warning: Explosive, handle with care!

4.7 Absolute ethyl alcohol.

4.8 Aqua regia: [hydrochloric acid (4.3) + nitric acid (4.4)] = (3 + 1), freshly prepared.

4.9 Hydrochloric acid (1 + 1).

4.10 Nitric acid (1 + 1).

4.11 Sodium hydroxide solution (20 g/l).

4.12 Nickel standard solution: weigh 0.500 0 g of metal nickel (of mass fraction >= 99.99%); place into a 100 mL beaker; put on the watch glass; add 20 mL of nitric acid (4.10) along the beaker wall; heat to dissolve; and dry by distillation at low temperature. Use a small amount of water to purge the watch glass; add 5 mL of hydrochloric acid (4.3); dry by distillation at low temperature; and repeat once. Add 10 mL of hydrochloric acid (4.3) to dissolve nickel salt; cool down; use water to transfer into a 1 000 mL volumetric flask; dilute to volume; and shake up. Then the mass concentration of the solution nickel is

0.50 mg/mL.

5.2 Analytical balance: grade 3; sensitivity

0.1 mg. Place specimen (7.1) into corundum crucible; add 4 g of sodium peroxide (4.1); use 1 g of sodium hydroxide (4.2) to cover the top; place into a high temperature furnace whose temperature has been raised to 650°C; maintain the temperature until fully melted (about 10 min); and take out for cooling. Place the crucible into a 200 mL beaker; add 100 mL of warm water; put on the watch glass; after the drastic reaction stops, add several drops of absolute ethyl alcohol (4.7); boil on the electric furnace for 3 min ~ 5 min; and take down for cooling. Filter; use hot sodium hydroxide solution (4.11) to wash the beaker and crucible and precipitate for 6 times ~ 8 times; use hot hydrochloric acid (4.9) to dissolve and precipitate in the original beaker; wash out the crucible; and place the solution on the electric hot plate to evaporate to dryness. Add 5 mL of hydrochloric acid (4.9) and a small amount of water to dissolve salts; use water to transfer into a 50 mL volumetric flask; dilute to volume; and shake up.

7.5 Preparation of calibration solution series In a series of 50 mL volumetric flasks, add respectively

0.00 mL,

0.50 mL,

10.00 mL of nickel standard solution (4.12); add 10 mL of hydrochloric acid (4.9); use water to dilute to volume; and shake up. The mass concentrations of the serial solution nickels are respectively 0.00 µg/mL, 5.00 µg/mL, 10.00 µg/mL … 100.00 µg/mL.

7.6 Determination Warning: Ignite or extinguish air-acetylene flame in accordance with the instructions to use of the atomic absorption spectrometer, in order to avoid causing possible explosion hazards! Use the flame atomic absorption spectrometer to measure the absorbance of nickel in the calibration solution series, blank solution and test solution (

7.4.1 and 7.4.2), at the wavelength of 352.5 nm, in accordance with the operating conditions of the instrument (refer to Annex A).

7.7 Plotting of calibration curve Plot the calibration curve using the nickel content as the abscissa and the absorbance as the ordinate; and obtain the corresponding nickel content from the calibration curve.