3566 NTERNATIONAL STANDARD (Tso INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOHAN OPTAHW3ALIMH HO CTAHIAPTH3ALIWW.ORGANISATION INTERNATIONALE DE NORMALISATION Sodium fluoride primarily used for the production of aluminium - Determination of chlorides content - Turbidimetric method Fluorure de sodium principalement utilise pour la production de I'aluminium -- Dosage des chlorures - Methode turbidimetrique First edition - 1976-04-01 MNsl Interat Doc jcct 1! ISO 3566-1976 (E) Ref. No. ISO 3566-1976 (E) UDC 661.833.361 : 546.13 : 543.436 Descriptors : sodium fluorides, chemical anatysis, determination of content, chlorides, turbidimetric analysis. Price based'on 2 pages Copyright International Organization for Standardization Notfor Resale FOREWORD ISO (the International Organization for Standardization) is a worldwide federation of national standards institutes (isO Member Bodies). The work of developing International Standards is carried out through IsO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 3566 was drawn up by Technical Committee ISO/TC 47. Chemistry, and circulated to the Member Bodies in September 1974. It has been approved by the Member Bodies of the following countries : Hungary Austria South Africa, Rep. of Belgium India Spain Bulgaria Ireland Switzerland Chile Israel Turkey Czechoslovakia Italy United Kingdom France Netherlands U.S.S.R. Germany Portugal Yugoslavia No Member Body expressed disapproval of the document. @ International Organization for Standardization, 1976 : Printed in Switzerland Copyright International Organization for Standardization INTERNATIONAL STANDARD ISO 3566-1976 (E) Sodium fluoride primarily used for the production of aluminium _ Determination of chlorides content - Turbidimetric method 1 SCOPE AND.FIELD,OF APPLICATION 6 PROCEDURE This International Standard specifies a turbidimetric method 6.1 Test portion for the determination of the chlorides content of sodium Weigh, to the nearest 0,01 g, 1 g of the dried test sample. fluoride primarily used for the production of aluminium. (See ISO 3428, sub-clause 2.3.) The method is applicable to products having a chlorides content, expressed as chlorine (Cl), equal to or greater 6.2 Preparation of the standard matching solutions than 0,005 % (m/m). Place 12,5 ml of the boric acid solution (4.2) into six of the Nessler tubes (5.1) and then the volumes of the standard chloride solution (4.4) shown in the following table : 2 REFERENCE ISO 3428, Sodium fluoride for industrial use -- Preparation Standard chloride Corresponding and storage of test samples. solution (4.4) mass of Cl ml mg 3 PRINCIPLE 0 0 0,50 0,025 Precipitation, in the presence of boric acid, of chloride ions 1,00 0,050 with silver nitrate and turbidimetric evaluation of the mass 2,00 0,100 of precipitate. 3,00 0,150 4,00 0,200 5,00 0,250 4 REAGENTS Dilute to 50 ml, introduce 1,0 ml of the nitric acid solution During the :.analysis, .use .only. .reagents of recognized (4.1) and'mix. analytical grade and only: distilled water. or water. of equivalent purity. 6.3 Preparation of the test solution 4.1 Nitric acid, p approximately 1,40 g/ml, about 68 % Place the test'portion (6.1) in a 100 ml one-mark volu- (m/m) solution. metric flask and add 60 ml of water and 25 ml of the boric acid solution (4.2). Shake until dissolved, 'dilute to the 4.2 Boric acid, 40 g/l solution. mark, and mix. Filter if necessary. Place 50,0 ml of this solution in one of the Nessler tubes 4.3 Silver nitrate, approximately 0,1 N solution. (5.1), add 1,0 ml of the nitri