3256 ISO NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOIHAI OPrAHH3ALIM HIO CTAHIAPTW3ALIWIN.ORGANISATION INTERNATIONALE DE NORMALISATION Aluminium and aluminium alloys -- Determination of magnesium -- Atomic absorption spectrophotometric method Aluminium et alliages d'aluminium -- Dosage du magnesium -- Méthode par absorption atomique First edition -- 1977-05-01 UDC 669.71 : 546.46 : 543.422 Ref. No. 1SO 3256-1977 (E) ISO 3256-1977 Descriptors : aluminium, aluminium alloys, chemical analysis, determination of content, magnesium, spectrophotometric analysis, atomic absorption spectroscopic analysis.: Price based on 4 pages Not for 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 Standards by the ISo Council. International Standard 1SO 3256 was developed by Technical Committee ISO/Tc 79, Light metals and their alloys, and was circulated to the member bodies in September 1976. It has been approved by the member bodies of the following countries : Italy South Africa, Rep. of Australia Belgium Japan Spain Bulgaria Korea, Rep. of Sweden Czechoslovakia Mexico Switzerland France Norway Turkey Germany U.S.A. Poland Hungary Portugal U.S.S.R. The member body of the following country expressed disapproval of the document on technical grounds : United Kingdom @ International Organization for Standardization, 1977 Printed in Switzerland Copyright International Organization for Standardization e from IHS ISO 3256-1977 (E) INTERNATIONAL STANDARD Aluminium and aluminium alloys - Determination of magnesium -- Atomic absorption spectrophotometric method 1 SCOPE AND FIELD OF APPLICATION 4.4 Hydrofluoric acid, p approximately 1,13 g/ml, about 40 % (m/m) solution. This International Standard specifies an atomic absorption spectrophotometric method for the determination of 4.5 Nitric acid, p approximately 1,40 g/ml, about 68 % magnesium in aluminium and its alloys. The method is (m/m) solution. applicable to products having magnesium contents between 0,01 and 5 %. 4.6 Aluminium, base solution : 20 g/l. Weigh, to the nearest 0,01 g, 20 g of previously pickled 2 REFERENCE aluminium free from magnesium (purity ≥ 99,99 %); place General conditions of application of atomic in a beaker of suitable size (1 000 ml, for instance), and absorption spectrophotometry.1) cover. Add, in small portions, 800 mi of the hydrochioric acid (4.1) and, if necessary, a drop of metallic mercury to assist the attack. If necessary, warm gently to help the 3 PRINCIPLE dissolution; then add a few drops of the hydrogen peroxide (4.2), and boil for a few minutes to remove the excess of Dissolution of the test portion with hydrochloric acid and hydrogen peroxide. After cooling, quantitatively transfer hydrogen peroxide. Atomization of this solution in an the solution so obtained to a 1 000 ml volumetric flask; acetylene/air flame, in the presence of strontium chloride, dilute to volume and mix. or in a dinitrogen monoxide/acetylene flame of the atomic absorption apparatus. 25 ml of this solution contain 0,5 g of aluminium. Comparison of the absorption of resonance energy of magnesium (wavelength 285,2 nm, normally, or 279,6 nm : 4.7 Aluminium, base solution : 1 g/l. less sensitive) with that of standard solutions. Transfer 50,0 ml of the base aluminium solution (4.6) to a 1 000 ml volumetric flask; dilute to volume and mix. 4 REAGENTS 100 ml of this solution contain 0,1 g of aluminium. During the analysis, use only reagent