Nitric acid for industrial use — Determination of ammoniacal nitrogen content — Spectrophotometric m...
Applicable to products containing more than 0.0001 % (m/m) of ammoniacal nitrogen. The procedure described is siutable for contents between 0.0001 % (m/m) and 0.0005 % (m/m). The principle of the analysis consists in distillation, with entrainment by steam, of the ammonia in the presence of an excess of sodium hydroxide and collection of the distillate in an excess of acid solution.…
Ammonium sulphate for industrial use — Determination of matter insoluble in water — Gravimetric meth...
Specifies the dissolution of a test portion in water; filtration under vacuum on the filter crucible, thorough washing of the filter crucible and detection of the absence of sulphates in the wash water by a barium chloride test, drying and weighing of the insoluble residue. Has also been approved by the IUPAC.
Ammonium sulphate for industrial use — Determination of iron content — 2,2'- Bipyridyl photomet...
Applicable to Fe contents of equal to or more than 0.0001 % (m/m). The reaction bases on the reduction of iron(III) by hydroxylammonium chloride. Formation of the complex between iron(II) and 2,2'-dipyridyl in a buffered medium (pH value between 4.5 and 6). Photometric measurement of the coloured complex at a wavelength of about 522 nm. Has also been approved by the IUPAC.
Ammonium sulphate for industrial use — Determination of free acidity — Titrimetric method
Applicable to products having a free acidity, expressed as H2 SO4 , equal to or more than 0.01 % (m/m). Dissolution of a test portion in Water and titration with standard volumetric sodium hydroxide solution in the presence of an indicator. The indicator must have a colour change in the pH range between 5.2 and 5.6. Has also been approved by the IUPAC.
Aluminium oxide primarily used for the production of aluminium — Determination of an adsorption inde...
Specifies two methods for industrial calcined products. The first, using carbon tetrachloride vapour, is applicable if the density of the material exceeds 3.75 g/ml; the second, using water vapour, is applicable if the density of the material is lower than 3.75 g/ml. The adsorptive power is evaluated by exposure of a previously dried sample to an atmosphere saturated with carbon tetrachloride or…
Sulphuric acid for industrial use — Determination of chlorides content — Potentiometric method
Applicable to products having chloride contents equal or more than 0.0003 % (m/m) expressed in hydrochloric acid. Specifies the potentiometric titration of the chloride ions with silver nitrate solution in a sulphuric acid medium using a silver measurement electrode and a calomel reference electrode.
