71.060.30 - Acids

Complements the second edition of ISO 3139/1976.

Contains guides concerning the procedure to be followed and the precautions to be observed for the taking, preparation and storage of samples with the view of assess their quality. Deals with the means of delivery, containers for taking samples, technical means for mixing and heating systems. Details the sampling of thermal-process and wet-process acids from large containers and mobile tanks and the safety measures. Has also been approved by the IUPAC.

Two cases are considered: sulphuric acid contents equal to or lower than 98 % (m/m) and sulphuric acid contents higher than 98 % (m/m). The principle is based on oxidation of a test portion with hydrogen peroxide and titration of the total acidity with a standard volumetric sodium hydroxide solution, in the presence of methyl red as indicator. - Replaces ISO Recommendation R 910-1968.

Applicable to products having a Ca content of more than 50 mg/kg. Soluble SiO2 present in the solution at levels lower than 5 g/ml does not interfere. The principle consists in addition, to a hydrochloric acid solution of the test portion, of sodium ions to promote and stabilize the emission of calcium and of lanthanum ions to suppress the interference of aluminium. Specifies the aspiration of the solution into an acetylene-dinitrogen monoxide flame. Photometric measurement of the absorption of ...view more

The principle consists in titration of a test portion with a standard volumetric solution of sodium hydroxide in presence of bromcresol green as indicator. Replaces ISO Recommendation R 904-1968.

Applicable to products whether or not they are homogeneous and whether or not they contain polyphosphoric acids. Specifies preliminary hydrolysis of the polyphosphoric acids by boiling in the presence of hydrochloric acid. The precipitation of the phosphoric acid is carried out in the form of quinoline phosphomolybdate in the presence of acetone. Filtration by a filter crucible, washing, drying and weighing of the precipitate.

Applicable to products having a water content between 0.01 % (m/m) and 0.5 % (m/m). Is supplemented by ISO 3700 and intended for reference purposes. Bases on addition of a cooled test portion to cooled dry pyridine containing 5 % of anhydous hydrogen fluoride. The apparatus for measuring the test portion and titration and the measuring vessel are shon in figures. Subsequent electrometric titration of the water with the Karl Fischer reagent.

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 sensitivity. Photometric measurement of the complex at a wavelength of about 600 nm.

Contains also titrimetric methods for determination of the total acidity, the hexafluorosilicic acid content and the non-volatile acids content and a method for calculating the hydrogen fluoric content. Specifies the scope and the field of application of these methods and declares the principle of the procedures. This second edition results from the incorporation of Addendum in the first one. Cancels and replaces the first edition ISO 3139/1974.

Applicable of products the SO2 content of which is equal to or more than 2 mg/kg. Based on the displacement of the sulphur dioxide present in the test portion by a current of pure nitrogen and absorption in a known volume of iodine solution. Titration of the excess of iodine with standard volumetric sodium thiosulphate solution. The diagram of the glass apparatus for absorption is shown in a figure.

This part contains a method for taking laboratory samples intended for the determination of the water content and the preparations of the test samples. Contains instructions for handling with the material. Applicable for taking samples of this highly corrosive liquid from road and rail tanks, drums and cylinders. The principle consists in allowing the liquid of one of these containers to flow in a cooled evacuated stainless steel cylinder or cylinders of not less than 1 kg total capacity. The ap...view more

Applicable to products having sulphate contents equal to or more than 0.0005 % (m/m). Analysis by reduction of the sulphate to sulphide by a mixture of hydriodic acid and hypophosphorus acid. Absorption of the hydrogen sulphide evolved in a mixture of acetone and sodium hydroxide solution. Titration with a standard volumetric solution of mercury(II) acetate in the presence of dithizone as indicator. Has also been approved by the IUPAC.

The turbidimetric method is applicable to products containing less than 0.1 % (m/m) of soluble sulphates. The principle consists in evaporation of a test portion to dryness and solution of the residue in hydrochloric acid. Measurement of the turbidity obtained by precipitation, under well defined conditions, of barium sulphate. Has also been approved by the IUPAC.