YS/T 252.1-2007Methods for chemical analysis of nickel matte. Determination of nickel content. Dimethylglyoxime gravimetric method (English PDF)

3.1 Hydrochloric acid (rho1.19 g/mL).

3.2 Hydrochloric acid (1 + 1).

3.3 Hydrochloric acid (1 + 24).

3.4 Nitric acid (rho1.42 g/mL).

3.5 Nitric acid (1 + 1).

3.6 Sulfuric acid (rho1.83 g/mL).

3.7 Ammonia (1 + 1).

3.8 Chloroform.

3.9 Nitric acid-potassium chlorate saturated solution: Dissolve potassium chlorate in

nitric acid (3.4) until saturated.

3.10 Potassium sodium tartrate solution (200 g/L), filter it before use.

3.11 Ammonium acetate solution (200 g/L), filter it before use.

3.12 Sodium thiosulfate solution (200 g/L), filter it before use.

3.13 Dimethylglyoxime ethanol solution (10 g/L), filter it before use.

3.14 Dimethylglyoxime-sodium hydroxide solution (10 g/L): Dissolve 15 g of sodium

hydroxide in 100 mL of water. After cooling to room temperature, dissolve 1 g of

dimethylglyoxime in the solution. Mix well.

3.15 Ferric persulfate solution (50 g/L).

3.16 Nickel standard stock solution:

Weigh 0.1000 g of metallic nickel (the mass fraction of nickel is >= 99.95%). Place it in

a 400 mL beaker. Add 10 mL of nitric acid (3.5). Cover it with a watch glass. Dissolve

it completely at low temperature. Add 2 mL of sulfuric acid (3.6). Continue heating

until a large amount of white smoke is gone. Cool down. Rinse the watch glass and cup

wall with water. Heat to dissolve the salts. Cool to room temperature. Transfer to a 1000

mL volumetric flask. Use water to make the volume reach the mark. 1 mL of this

solution contains 100 µg of nickel.

3.17 Nickel standard solution:

Pipette 10.00 mL of nickel standard storage solution (3.16) into a 200 mL volumetric

flask. Use water to make the volume reach the mark. 1 mL of this solution contains 5

µg of nickel.

4.1 Spectrophotometer.

4.2 Electric constant temperature water bath.

4.3 Electric constant temperature drying oven.

4.4 Glass sand core crucible, G4 (pore diameter 7 µm ~ 16 µm/5 µm ~ 15 µm).

4.5 Suction filter bottle.

5.4.1 Collect the filtrate from 5.3.3. Cool it. Transfer it into a 500 mL or 1000 mL

volumetric flask depending on the volume. Use water to make the volume reach to the

mark.

5.4.2 Dispense 100.00 mL of the mixed filtrate (5.4.1) into a 250 mL separatory funnel.

Use hydrochloric acid (3.2) and ammonia water (3.7) to adjust the pH of the solution to

about 6.5. Add 15 mL of chloroform (3.8). Shake for 2 minutes. Let it stand for 5

minutes. After layering, move the organic phase into another separatory funnel. Add 15

mL of chloroform (3.8) to the aqueous phase, to repeat the extraction once. Combine

the organic phases. Discard the aqueous phase.

5.4.3 Add 15 mL hydrochloric acid (3.3) to the organic phase (5.4.2). Shake for 1 minute.

Let it stand for stratification. Transfer the organic phase into another separatory funnel.

Add 15 mL of hydrochloric acid (3.3) for back extraction once. Combine the aqueous

phase in a 100 mL beaker.

5.4.4 Heat the solution (5.4.3) in the beaker at low temperature, to evaporate to a volume

of about 2 mL. Remove to cool it. Add 2 mL of nitric acid (3.4). Continue heating and

evaporate to dryness. Cool it. Add hydrochloric acid (3.2) and heat slightly to dissolve

the salts. After cooling, transfer it into a 50 mL volumetric flask.

5.4.5 Add 5 mL of persulfate lock solution (3.15) and 5 mL of dimethylglyoxime-

sodium hydroxide solution (3.14). Mix well. Let it stand for 10 minutes. Use water to

make the volume reach to the mark.

5.4.6 Pipette part of the test solution (5.4.5) into a 1 cm cuvette. Use the reagent blank

as a reference, to measure the absorbance at the wavelength of 510 nm on the

spectrophotometer. Find out the corresponding nickel amount from the working curve.

5.4.7 Drawing of working curve:

Pipette 0.00 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL, 5.00 mL of nickel standard

solutions (3.17). Place them in a set of 50 mL volumetric flasks, respectively. Proceed

the following steps in accordance with (5.4.5). Using the reagent blank as a reference,

measure the absorbance at the wavelength of 510 nm with a spectrophotometer. Draw

a working curve, using the nickel amount as the abscissa and the absorbance as the

ordinate.

Note: The nickel content in the filtrate shall not exceed 0.20% of the nickel content in the

original sample.