ISO 900:1977 pdf download.Aluminium oxide primarily used for the production of aluminium Determination of titanium content — Diantipyrylmethane photometric method.
ISO 900 specifies a diantipyrylmethane photometric method for the determination of the titanium content of aluminium oxide primarily used for the production of aluminium.
The method is applicable to products having a titanium content, expressed as titanium dioxide (Ti02), equal to or greater than 0,00 1 % (rn/rn).
2 REFERENCES
ISO 802, Aluminium oxide primarily used for the production of aluminium — Preparation and storage of test samples.
ISO 804, Aluminium oxide primarily used for the production of aluminium — Preparation of sample solution for analysis — Method by alkaline fusion.
Allow to cool, immerse the dish and its contents in a beaker containing 95 ml of water and 5 ml of the same sulphuric acid solution and heat on a boiling water bath until the solution is completely clear.
Remove the platinum dish, wash it carefully with water, transfer the solution and the washings quantitatively to a 500 ml one-mark volumetric flask, dilute to the mark and mix.
Cool and transfer the solution quantitatively to d beakei of suitable capacity containing 100 ml of water. Add, drop by drop, approximately 0,1 N potassium permanganate solution until the colour of the solution is permanently pink. Transfer the solution quantitatively to a 500 ml one-mark volumetric flask, dilute to the mark and mix.
1 ml of this standard solution contains the equivalent of
0,400 mg of Ti02.
Add 25 ml of the sulphuric acid solution (4.4) to each tlask. Dilute with water to about /0 ml, add 3 ml of the ascorbic acid solution (4.5) and 3 drops of the copper(ll) sulphate solutIon (4.6) and mix. Allow to stand for 20 mm, add 10 ml of the diantipyrylmethane solution (4.7), dilute to the mark and mix.
6.3.2 Photometric measurements
After at least 40 mm, carry out the photometric measurements using the spectrophotometer (5.2) at a wavelength of about 420 nm or the photoelectric absorptiometer (5.3) fitted with suitable filters, after having adjusted the instrument to zero absorbance against the compensation solution.
NOTE — The absorbance of the solution is stable for about 24 h.
6.3.3 Plotting of the calibration graph
Plot a graph having, for example, the values of the masses, in milligrams, of titanium dioxide (Ti02) contained in 100 ml of standard colorimetric solution, as abscissae and the corresponding values of absorbance as ordinates.
to stand for 20 mm, add 10 ml of the diantipyrylmethane solution (4.7), dilute to the mark and mix.
6.4.2 Photometric measurement
After at least 40 mm, carry out the photometric measurement following the procedure specified in 6.3.2, after having adjusted the instrument to zero absorbance against water.
6.5 Blank test
6.5.1 Preparation of the blank test solution
Proceed in accordance with sub-clause 6.4.2 of ISO 804, replacing the nitric acid solution (4.5 of ISO 804) by the sulphuric acid solution (4.3) and diluting the solution to 250 ml.
6.5.2 Colour development
Proceed as specified in 6.4.1.ISO-900-1977