ISO 900:1977 download.Aluminium oxide primarily used for the production of aluminium — Determination of titanium content — Diantipyrylmethane photometric method.
1 SCOPE AND FIELD OF APPLICATION
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.
3 PRINCIPLE
Alkaline fusion of a test portion and extraction of the fused mass with sulphuric acid solution. Formation of the titan ium-d iantipyrylmethane complex in approximately 4,6 N sulphuric acid solution.
Photometric measurement of the coloured complex at a wavelength of approximately 420 nm.
4 REAGENTS
During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity.
4.1 Sodium carbonate, anhydrous.
4.2 Boric acid (H3B03). or
4.2.1 Sodium tetraborate, anhydrous (Na2 B407).
4.3 Sulphuric acid, approximately 8 N solution.
4.4 Sulphuric acid, approximately 18 N solution.
4.5 Ascorbic acid. 30 g/l solution. Use a freshly prepared solution.
4.6 Copper(ll) sulphate pentahydrate (CuSO4 .5H20),
50 g/l solution.
4.7 Diantipyrylmethane, 509/I hydrochloric acid solution.
Dissolve 5 g of 4,4’-methylenediantipyrine (diantipyrylmethane) (C23 H24N402) in 100 ml of approximately 1 N hydrochloric acid solution.
4.8 Titanium, standard solution corresponding to 0.400 g of titanium dioxide (Ti02) per litre.
Prepare the solution by either of the following two methods:
4.8.1 In a platinum dish of suitable capacity, weigh, to the nearest 0,000 1 g, 0,601 5 g of dipotassium hexafluorotitanate (K2TiF6) previously dried at about 50 °C and cooled in a desiccator. Moisten the product with a few drops of water arid then add 15 ml of sulphuric acid solution, p approximately 184 g/ml. Evaporate carefully almost to dryness in a well-ventilated fume cupboard. Repeat the operation until the fluorine is completely expelled, using each time 5 to 6 ml of the same sulphuric acid solution. Finally, add 3 ml of the same sulphuric acid solution and heat until the residue is completely dissolved.
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.
1 ml of this standard solution contains the equivalent of
0,400 mg of Ti02.
4.8.2 Weigh, to the nearest 0,000 1 g, 0,886 5 g of
dipotassium titanyl dioxalate dihydrate I K2TiO(C2 04 )2•
2H201 and place in a Kjeldahl flask of capacity about
100 ml. Add 080 g of ammonium sulphate and 10 ml of
sulphuric acid solution, p approximately 1,84 gIml. Heat
carefully until the reaction subsides and then boil for
10 mm.
Cool and transfer the solution quantitatively to a beaket 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
0,400mg of Ti02.
NOTE — If dlpotassium hcxofluorotitonote or dipotassium titanyl dioxalate dihydrete is not available, the following alternative procedure may be adopted:
In a platinum crucible of suitable capacity, we4. to the nearest 0,000 1 g, 0,200 Og of titanium dioxide (Ti02) previously calcined at 1 200°C and cooled in a desiccator. Add 4 g of potassium pryosulphate (K2S207) and fuse carefully at about 1 200°C. Allow to cool and place the crucible end contents in a beaker of suitable capacity. Add 100 ml of the sulphuric acid soluhon (4.4) and heat gently to dissolve the melt. Remove the crucible and wash it with hot water, collecting the washings in the beaker. Transfer the solution and the washings quantItatlvel to a 500 ml onu.nik volumetric flask, dilute to the mark and mix.
4.9 Titanium0 standard solution corresponding to 0.040 g of titanium dioxide (Ti02) per litre.
Transfer 50,0 ml of the standard titanium solution (4.8) to
a 500 ml one-mark volumetric flask, dilute to the mark and
mix.
1 ml of ISO 900 solution contains the equivalent of
0.040 mg of Ti02.
Prepare this solution at the time of use.
4.10 Titanium, standard solution corresponding to 0.0 10 g of titanium dioxide (Ti02) per litre.
Transfer 25,0 ml of the standard titanium solution (4.9) to a 100 ml one-mark volumetric flask, dilute to the mark and mix.
1 ml of this standard solution contains the equivalent of
0.010mg of Ti02.
Prepare this solution at the time of use.
5 APPARATUS
Ordinary laboratory apparatus and
5.1 Burette, graduated in 005 ml, complying with the
requirements of ISO/R 385.
5.2 Spectrophotometer, or
5.3 Photoelectric absorptiometer, fitted with suitable filters, having maximum absorption at about 420 nm.
6 PROCEDURE
6.1 Preparation of the test solution (principal solution P)
Proceed in accordance with sub-clauses 6.1, 6.2 and 6.3 of ISO 804, replacing the nitric acid solution (45 of ISO 804) by the sulphuric acid solution (4.3) and diluting the principal solutions to 250 ml.
6.2 Test portion
Place 50,0 ml of the test solution (6.1), containing 1.000 g
of the dried sample (see wb-clause 3.3 of ISO 802), in a
100 ml one-mark volumetric flask.
NOTE — If the Ti02 content is greater than 001 % (rn/rn). reduce the test portion proportionately and take this into account In the calculation of the results.
6.3 Preparation of the calibration graph
6.3.1 Preparation of the standard colorimetric solutions, for photometric measurements using 4 cm cells
Into a series of seven 100 ml one-mark volumetric flasks transfer, by means of the burette (5.1), the volumes of the standard titanium solution (4.10) shown in the following tdble
Add 25 ml of the sulphuric acid solution (4.4) to each tlask. Dilute with water to about 70 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.
6.4 Determination
6.4.1 Colour development
To the test portion (6.2) placed in the 100 ml one-mark volumetric flask, add 20 ml of the sulphuric acid solution (4.4), 3 ml of the ascorbic acid solution (4.5) and 3 drops
of the copper(II) 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.
6.4.2 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.
6.5.3 Photometric measurement
Aftei at least 40 mm, c,iy OUt 1lit photometric measurement following the procedure specified in 6.3.2, after having adjusted the instrument to zero ahcnrbance against water.
7 EXPRESSION OF RESULTS
From the calibration graph (see 6.3.3), determine the masses of titanium dioxide (Ti02) corresponding to the absorbance of the test solution and to that of the blank test solution.
m0 is the mass, in grams, of thc test portion used for the preparation of the test solution (6.1);
m1 is the mass, in milligrams, of titanium dioxide found in the aliquot portion of the test solution (6.1);
m2 is the mass, in milligrams. of titanium dioxide found in a corresponding aliquot portion of the blank test solution.
8 TEST REPORT
The test report shall include the following particulars
a) the reference of the method used;
b) the results and the method of expression used;
c) any unusual features noted during the determination;
d) any operation not included in ISO 900 or in the International Standards to which reference is made, or regarded as optional.
ISO 802 Preparation and storage of test samples.
ISO 803 — Determination of loss of mass at 300 °C (conventional nioisture.
ISO 804 — Preparation of solution for analysis — Method by alkaline fusion.
ISO 805— DeterminatIon of Iron content — 1,10•Ptienanihrollne photometric method.
ISO 806 Determination of loss of mass at 1 000 and 1 200 °C.
ISO 900 — Determination of titanium content — Diantipyrylmethane photometric method.
ISO 901 — Determination of absolute density — Pyknometer method.
ISC) 902 — Mase,rment of the angle of repose.
ISO 903 — Determination of untamped density.
ISO 1232 — Determination of silica content — Reduced molybdosilicate spectrophotometric method.
ISO 1617 — Determination of sodium content — Flame emissiuil spectrc,piiuiomelric method.
ISO 1618 — Determination of vanadium content — N-BenzoylN-phenylhydroxylamine photometric method.
ISO 2069 — Determination of calcium content — Flame atomic absorption method.
ISO/H 2070 — Determination of calcium content — Spectrophotometric method using naphthalhydroxamic acid.
ISO 2071 — Determination of zinc content — Flame atomic absorption method.
ISO/A 2072 — Determination of zinc content — PAN photometric method.
ISO 2073 — Preparation of solution for analysis — Method by hydrochloric acid attack under pressure.
ISO 2828 — Determination of fluorine content – Alizarin complexone and lanthanum chloride spcctrophotometric mcthod
ISO 2829 — Determination of phosphorus content — Reduced phosphomolybdate spectrophotonietric method.
ISO 2865 — Determination of boron content — Curcumirt spectrophotometric method.
ISO 2928 — Particle size analysis — Sieving method.
ISO 2927 — Sampling.
ISO 2961 — Determination of an adsorption index.
ISO 3390 — Determination of manganese Content — Flame atomic absorption method.