71.060.50 - Salts

This European Standard is applicable to sodium hexafluorosilicate used for treatment of water intended for human consumption. It describes the characteristics of sodium hexafluorosilicate and specifies the requirements and the corresponding test methods for sodium hexafluorosilicate. It gives information on its use in water treatment. It also determines the rules relating to safe handling and use of sodium hexafluorosilicate (see Annex B).

ISO/TR 4277:2009 describes a conventional test for the evaluation of the free fluorides content of natural, artificial and recovered cryolite. This method is applicable to products having free fluorides content greater than 0,15 % (mass fraction) of AIF3 or 0,4 % (mass fraction) of NaF.

ISO 20292:2009 covers materials for the production of primary aluminium. ISO 20292:2009 specifies a method for the determination of the resistance of dense refractory bricks to cryolite melt with excess sodium fluoride.

Applicable to products having Ca contents equal to or more than 50 mg/kg. The presence of soluble SiO2 up to 5 g/ml in the test solution does not interfere. Hydrolysis by boiling a test portion in hydrochloric acid medium. Addition of sodium ions, until a constant concentration is obtained, to stabilize the promotion and emission of Ca; addition of lanthanum chloride to increase the sensitivity of the method. Aspiration of the solution into a dinitrogen monoxide-acetylene flame. Spectrometric me...view more

Specifies a method based on the fusion of a test portion with sodium carbonate and boric acid and dissolution in perchloric acid solution, followed by formation of the ammonium molybdophosphate complex and extraction of the complex with isobutyl acetate. The solution is absorbed into an acetylene/dinitrogen monoxide flame and the molybdenum, and hence the phosphorus, is determined by measuring the absorbance of the 379,8 nm line emitted by a molybdenum hollow-cathode lamp.

Covers a method, the orinciple of which consists in preparing tablets from a mixture of the test portion and a binder and measuring the intensity of the K line emitted by the sulphur. The measured intensity is then compared with the intensity of emission of standard tablets of known sulphur content. The method is applicable to products having sulphur contents between 0,01 and 2 % (m/m).

Applicable to the determination of losses equal to or more than 0.008 % (m/m). The principle consists in drying of a test portion at (105 1) °C for 6 h. The dried test portion is retained for the other determinations given in the annex. Has also been approved by the IUPAC.

Applicable to products having contents, expressed as phosphorus pentoxide, of 0.005 % (m/m) to 0.05 % (m/m). The residue from the determination of the loss of mass according to ISO 5444 is used to prepare the test sample. Dissolution in dilute hydrochloric acid and nitric acid solutions. Formation of the yellow molybdovanadate and spectrophotometric measurement at a wavelength of about 420 nm. Calculation of the content from the measured absorbance.

Applicable to products having a content, expressed as sulphur trioxide, equal to or more than 0.1 % (m/m). Bases on alkaline fusion of a test portion with a mixture of sodium carbonate and boric acid. Extraction of the fused mass with perchloric acid solution and precipitation of the sulphate ions with barium chloride in an acidified medium. Filtration on a fine-texture, ashless filter paper (pore diameter approximately 0.4 to 1.0 m). Calcination after drying in an electric oven at (850 20) °C. ...view more

With respect to the free acidity, applicable to products having contents, expressed as H2 SiF6 , equal to or more than 0,1 % (m/m). First, determination of the free acid contents by titration of an ice-cooled test portion with a standard volumetric sodium hydroxide solution in the presence of potassium nitrate and using bromothymol blue as indicator, then, followed by titration at near boiling temperature with standard volumetric sodium hydroxide solution to the appearance of a permanent blue co...view more

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 chloride, formation of the complex iron(II)-1, 10-phenathroline in a buffered medium at pH value between 3,...view more

Describes the preparation of the calibration graph and the dissolution of a test portion in concentrated sulphuric acid and heating on a hot-plate until the hydrofluoric acid has evaporated. Treatment of the residue with concentrated hydrochloric acid. Aspiration of the solution into an acetylene/dinitrogen monoxide flame and spectrophotometric measurement of the absorption of the 422.7-nm line emitted by a calcium hollow cathode lamp.

Specifies the procedure for the preparation of crude samples and dried samples and of natural and synthetic materials having a molar ratio sodium fluoride/aluminium trifluoride between 3 and 1,7 approximately. The crude sample is intended for the determination of geometric characteristics, for certain physical and physico-chemical tests and for moisture determination. The dried sample serves especially for chemical tests. The principle of the procedure consists in grinding followed by sieving of...view more

Specifies the determination for natural and synthetic materials having a molar ratio sodium fluoride/aluminium trifluoride between 3 and 1,7 approximately. The principle consists in fusion of a test portion with sodium carbonate, separation of fluorine by distillation with sulphuric acid or perchloric acid. Titration with thorium nitrate solution in presence of sodium alizarinsulphonate/methylene blue as indicator. Alternatively, the thorium nitrate titration may be made using only sodium alizar...view more

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 fused mass in excess nitric acid so that the pH value is between 0,7 and 0,9. Formation of the (Yell...view more

Specifies a gravimetric method for the determination of moisture content of cryolite. Describes the principle, the apparatus, the procedure, gives the expression of results and the test report. An annex lists the ISO Publications of concern.

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.

Three cases, defined by a preliminary test, are envisaged: silicates containing neither sulphides nor chlorates; silicates containing sulphides; silicates containing chlorates. The method based on boiling of an acidified test portion containing methyl orange and with a lead paper strip in the vapour. The presence of sulphides produces blackening of the paper and the presence of chlorates decolorizes the methyl orange. Volumetric*measurement of carbon dioxide evolved from silicates containing nei...view more

The principle of the procedure based on titration of a test portion with a standard volumetric hydrochloric acid solution, in the presence of methyl orange as indikator. The alkalinity is expressed as a percentage by mass of sodium oxide potassium oxide.

Relates to crude samples intended for the determination of moisture content and dried samples for chemical tests. Processing by grinding and sieving until the sample passes completely through a sieve of mesh aperture 0.125 mm. Thoroughly mixing and drying and storing in a tightly closed container.