71.060.50 - Salts

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.

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. Weighing of the residue.

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 colour.

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 (Yellow) oxidized molybdosilicate under clearly defined conditions of acidity, temperature, time and concentration of reagents. Selective reduction in the presence of tartaric acid and measurement at a wvelength of about 815 nm.

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 3,5 and 4,2. Photometric measurement of the coloured complex at a wavelength of about 510 nm. Applies ISO Recommendation R 1694-1970.

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 the sample until the whole passes through a sieve of mesh aperture 0,125 mm. Thorough mixing and drying at approximately 110 °C.

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 alizarinsulphonate, the end-point being*spectrophotometrically determined at 525 nm.

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.

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.

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 neither sulphides nor chlorates by reaction with a hydrochloric acid solution. The principle for the oxidation of sulphides and the reduction of chlorates are specified.

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.

The procedure is based on evaporation to dryness of a test portion previously acidified with hydrochloric acid. Dissolution of the soluble salts, filtration and washing of the insoluble matter. Second evaporation of the filtrate and washings under the same conditions, further dissolution of the soluble salts, filtration and washing. Calcination and weighing of the two lots of insoluble matter simultaneously. Volatilization of silica by heating with hydrofluoric and sulphuric acids and weighing of the residue after calcination. The*difference in mass represents the silica present in the test portion.

The method specified are applicable directly to soluted mateials or materials soluble in boiling water. In case of solid chemicals not readily soluble in boiling water, a special preliminary treatment is necessary. Precautions shall be taken in order to avoid absorption of moisture and carbon dioxide. All tests and analyses shall be carried out at a temperature of 20 °C. In order to avoid incorrect results use only reagents of analytical grade. Replaces ISO Recommendation R 1686-1970

The principle of the method consists in dissolution of a test portion and filtration of the solution through a tared filter. Washing of the insoluble matter at approximately 50 C until the washings are no longer alkaline. Drying of the residue and weighing. Replaces ISO Recommendation R 746-1968.

Specifies a titrimetric test method for the determination of the basicity of soluted material. The principle of the procedure consists in solution of a test portion in water, filtration of the solution and titration with a standard volumetric solution of hydrochloric acid in presence of methyl orange as indicator. Repaces ISO Recommendation R 740-1968.

The document specifies the formula for the calculation. In this ratio, only sodium oxide and potassium oxide combined in the form of silicates is considered. Replaces ISO Recommendation R 1689-1970.

Based on hydrolysis of a test portion by prolonged boiling in the presence of hydrochloric acid. Precipitation of the phosphate ions in the form of quinoline phosphomolybdate in the presence of acetone. Filtration by means of a filter crucible, washing, drying and weighing of the precipitate.

Based on dissolution of a test sample in water, distillation of the ammonia after displacement by an alkali solution. Absorption in an excess of standard volumetric sulphuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of methyl red/methylene blue mixed indicator. A typical distillation apparatus is shown in a figure.

Not applicable to the analysis of mixtures for agricultural use such as herbicides or pesticides. Indicates the risk in handling with clorates. Dissolution of the test portion in water and reduction by a known quantity, in access, of an iron(II) salt in a sulphuric acid and orthophosphoric acid medium. Titration of the excess iron(II) salt with a standard volumetric solution of potassium dichromate in the presence of barium diphenylamine-4-sulphonate solution as indicator.

The methods are applicable as alternatives to products for which the molar ratio NaF/AlF3 is equal to about 3. The principle of the flame emission method consists in atomization of the test solution in a flame of oxygen/hydrogen and determination by measurement of the intensity of the radiation at 589 nm. The principle of the flame atomic absorption method is based on atomization in an air/acetylene flame and measuremnt of the absorption of the 589 nm line emitted by a sodium hollow-cathode lamp. The preparation of the test solution is carried out by dissolution of a test portion in hydrochloric acid and water after attack by concentreted sulphuric acid.

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.

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.

The principle consists in dissolution of a test portion, separation of all insoluble matter by filtration of the solution by vacuum through a filter crucible, drying and weighing. Has also been approved by the IUPAC.

The principle consists in separation of the fluorine from a test portion by distillation with sulphuric acid or perchloric acid. Titration with thorium nitrate solution using sodium alizarinsuphonate and methylene blue as indicators. Alternatively the thorium nitrate titration may be carried out using sodium alizarinsuphonate alone as indicator, the end-point being determined spectrophotometrically under carefully defined conditions. The absorbance at a wavelength of 525 nm shall reach the arbitrary value of 0.6. Has also been approved by the IUPAC.

Describes a gravimetric method of analysis. It consists in drying a test portion in an electric oven ventilated by convection at (110 2) 0C. Calculation of the moisture content by the loss of mass. Has also been approved by the IUPAC.

Applicable to products having a normal composition for which the molar ratio NaF/AlF3 is equal to about 3. Dissolution of a test portion in concentrated suphuric acid and elimination of hydrogen fluoride. Treatment with hydrochloric acid and water. Atomization of the solution into an acetylene measurement of the absorption of the 309.3 nm line emitted by an aluminium hollow cathode lamp. Has also been approved by the IUPAC.

The method is applicable to products with a content greater than 0,01 % (m/m). It is not applicable to the analysis of mixtures of products such as herbicides and insecticides. The principle consists in titration of the chloride ions with mercury(II) nitrate in the presence of diphenylcarbazone as indicator.

The method is applivable to products with a content greater than 0,02% (m/m). It is not applicable to the analysis of mixtures such as herbicides and insecticides. The principle is based on heating of a test portion, spread in form of a thin layer, at 105 °C. Weighing and calculation of the loss of mass by difference before heating and after heating.

The method is applicable to the analysis of products with a content greater than 0,01 % (m/m). The method is not applicable to mixtures based on sodium chlorate, such as herbicides and insecticides. The test portion is dissolved in water. Filtration of the resultant solution through a filter crucible. Washing, drying and weighing of the residue.

The method is applicable to products having a content equal to or greater than 0,1 mg/kg. The principle concists in reduction of the iron(III) by hydroxylammoniumchloride. Formation of a iron(II)-1,10-phennanthroline complex in a buffered solution. Photometric measurement of the coloured complex at a wavelength of about 510 nm.

The method is applicable to water-soluble salts for contents greater than 0,001 % (m/m). In a special case, the determination of ions in a principal solution prepared in an acid medium is pooible. The principle consists in dissolution of a test portion and separation of insoluble matter. Titration of the filtrate obtained according to ISO 2479 using disodium ethylendiamintetraacetate (EDTA) in the presence of glyoxal-bis-(2-hydroxyanil) (GBHA) and mordant black 11 (Cl 14645) respectively as indicators.

The principle of the analysis consists in titration of the halogen ions with mercury(II) nitrate in the presence of diphenylcarbazone as indicator. The main solution for the determination is prepared according to ISO 2479.

Specifies a method for the determination of the conventional moisture content. The principle consists drying of a test portion in an oven at (110 +- 2) °C to constant mass.

The method can be applied provided the Fe203 content does not exceed 0,15 . It can also be applied to products with molar ratio of NaF to AlF3 between approximately 3 and 1,7. The principle consists in dissolution of a test portion by acid fusion using potassium pyrosulphate and recovery by hydrochloric acid. Separation of the mixture by precipitation of aluminium, with ammonium benzoate , in an acetic reducing medium. Dissolution of the precipitate and reprecipitation as aluminium tri(quinolin-8-oxide) in an acetic buffer medium. Filtration, washing, drying of the precipitate at a temperature of 130 °C and weighing.

The method is applicable to water soluble sulphate, in the product, but also to sulphates in a principal solution prepared in an acid medium. The principle consists in dissolution of a test portion and separation of the insoluble residue. Precipitation of the sulphate ions by barium chloride in a boiling acid medium. Filtration, washing and ignition of the precipitate. Weighing of the residue.

Insoluble substances shall be defined by the conditions described in this document. The object is not to dissolve all the impurities but only those of interest to users. The method is applicable to the analysis, carried out inaqueous medium or in acid medium. The principle consists in solution of the test portion in water, filtration, drying and weighing of the insoluble residue. Dilution of the filtrate to form the main solution for carrying out other determinations.

The method is applicable to products corresponding to the general formula M2O . xSiO2, where the values of x lie between 1,5 and 3,5 in the case of sodium silicates and 1,9 and 3,9 in the case of potassium silicates. Because of the difficulty ancountered in dissolving fine particles of these products, the sample is first sieved to remove these fines. The procedure consists in dissolution of the test portion in carbon dioxide-free water, by treatment in an autoclave. Filtration and weighing of the insoluble matter on a tared filter crucible. Dilution of the filtrate to a given volume, from which aliquot samples are taken in order to carry out the different determinations.

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).

This document 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).

Scope
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.

This European Standard is applicable to sodium hydrogen sulfite used for treatment of water intended for human consumption. It describes the characteristics of sodium hydrogen sulfite and specifies the requirements and the corresponding test methods for sodium hydrogen sulfite. It gives information on its use in water treatment.