Phosphoric acid for industrial use (including foodstuffs) — Determination of oxides of nitrogen cont...
Applicable to products having a content, expressed as N, equal to or more than 0.2 mg/kg. Consists in oxidation of nitrous nitrogen to nitric nitrogen by potassium permanganate and reaction of nitrogen(V) with 3,4-xylenol under specified conditions to form a nitrate derivative. Subsequent destillation of the nitrate derivative and absorption in sodium hydroxide solution. Spectrophotometric…
Aluminium oxide primarily used for the production of aluminium — Determination of vanadium content —...
The method is applicable to products having vanadium contents between 0,0003 % (m/m) and 0,016 % (m/m), provided that the content of chromic oxide and titanic oxide does not exceed 0,002 % (m/m) and 0,006 % (m/m), respectively. The principle consists in a previous oxidation of the vanadium contained in the test sample to vanadium(V) by patassium permanganate in sulphuric acid solution. Formation…
Cryolite, natural and artificial — Determination of silica content — Reduced molybdosilicate spectro...
Specifies methods of test for natural and synthetic materials having a molar ratio sodium fluoride/aluminium trifluoride between 3 and 1,7 approximately. The method is applicable to products the phosphorus pentoxide content of which does not exceed 0,02 % (m/m). The procedure consists in alkaline fusion of a test portion by means of a mixture of sodium carbonate and boric acid. Dissolution of the…
Aluminium oxide primarily used for the production of aluminium — Preparation and storage of test sam...
Specifies the preparation of laboratory samples, crude samples for the determination of certain geometric properties and physical and pysico-chemical tests including the determination of moisture content and dried samples. The principle consists in grinding and sieving of the sample until passing completely through a sieve of meshes having apertures of 0,2 mm. Mixing and drying at about 300 °C.…
Aluminium oxide primarily used for the production of aluminium — Determination of iron content — 1,1...
Applicable to Fe contents, expressed as Fe2 O3 , equal to or more than 0.005 % (m/m). Specifies the preliminary reduction of iron (III) by means of hydroxylammonium chloride. Formation of the iron(II)-1,10-phenanthroline complex in a buffered (pH value between 3.5 and 4.2). Photometric measurement at a wavelength of about 510 nm. Replaces ISO Recommendation R 805/1968.
Cryolite, natural and artificial — Determination of iron content — 1,10- Phenanthroline photometric ...
Applies for the determination of natural and synthetic materials having a molar ratio sodium fluoride/aluminium trifluoride between 3 and 1,7 approximately. The method is applicable to products having an iron content equal to or greater than 0,020 % (m/m). The principle consists in dissolution of a test portion by either alkaline or acid fusion. Reduction of iron(III) with hydroxylammonium…
Aluminium oxide primarily used for the production of aluminium — Determination of silica content — R...
The method is applicable to products having a silica content between 0.005 % (m/m) and 0.025 % (m/m) provided that the content of phosphorus pentoxide plus vanadium pentoxide does not exceed 0.02 % (m/m). The principle of the method is based on the formation of oxidized molybdosilicate (yellow) under well-defined conditions of acidity, concentration of reagents, temperature and time. Selective…
Phosphoric acid and sodium phosphates for industrial use (including foodstuffs) — Determination of f...
Applicable to products the F content of which is equal to or more than 0.5 mg/kg. Specifies the separation of the element from a test portion by steam distillation in a phosphoric acid medium. Formation of a blue-coloured complex with a combined reagent alizarin complexone/lanthanum nitrate in a buffered medium at the pH of 4.6. Addition of acetone to increase the stability of the complex and the…
Aluminium oxide primarily used for the production of aluminium — Determination of calcium content — ...
This method is applicable to products having Ca contents greater than 0,003 % (m/m). The principle consists in dissolution of a test portion by the influence of hydrochloric acid under pressure. Addition of sodium ions to promote and to stabilize the emission of calcium, and of lanthanum ions or triethanolamine to increase the sensitivity. Aspiration of the solution into an acetylene-dinitrogen…
Sodium fluoride primarily used for the production of aluminium — Determination of soluble sulphates ...
Applicable to products having SO4 contents of more than 0.05 % (m/m). Covers the dissolution of the test portion in hydrochloric acid and evaporation in hydrochloric acid solution for drying. Dissolution of the residue in a hydrochloric acid solution. Measurement of the turbidity obtained by precipitation, under specified conditions, of barium sulphate using a spectrophotometer at a wavelength of…
