1118 TSO NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAA OPFAHM3AUWH NO CTAHAAPTW3ALWM-ORGANISATION INTE RNATIONALE DE NORMALISATION Aluminium and aluminium alloys - Determination of titanium -- Spectrophotometric chromotropic acid method Aluminium et alliages d'aluminium - Dosage du titane -- Methode spectrophotometrique a I'acide chromotropique First edition - 1978-12-15 ISO 1118-1978 (E) UDC 669.71 : 543.42 : 546.821 Ref. No. 1SO 1118-1978 (E) Descripteurs : aluminium, aluminium alloys, chemical analysis, determination of c spectrophotometric analysis. Price based on 6 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 member body interested in a subject for which a technicat 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 technicai committees are circuiated to the member bodies for approval before their acceptance as International Standards by the iso Council. International Standard ISO 1118 was developed by Technical Committee ISO/TC 79, Light metals and their alloys. It was submitted directly to the ISO Council, in accordance with clause 6.13.1 of the Directives for the technical work of IsO. It cancels and replaces ISO Recommendation R 1118-1969, which had been approved by the member bodies of the following countries : Belgium Iran South Africa, Rep. of Canada Israel Spain Sweden Colombia Italy Czechoslovakia Japan Switzeriand Egypt, Arab Rep. of Korea, Rep. of Thailand France Netherlands Turkey New Zealand Germany, F.R. United Kingdom Hungary Norway U.S.A. India Poland U.S.S.R. No member body had expressed disapproval of the document. @ International Organization for Standardization, 1978 Printed in Switzertand Copyright International Organization for Standardization Not for Resale ISO 1118-1978 (E) INTERNATIONAL STANDARD Aluminium and aluminium alloys - Determination of titanium -- Spectrophotometric chromotropic acid method 3.2 Sodium hydroxide, 80 g/l or approximately 2 N 1 SCOPE AND FIELD OF APPLICATION solution. This International Standard specifies a general method for In a nickel dish, dissolve 80g of sodium hydroxide in the spectrophotometric determination of titanium in water. After cooling, make up the votume to 1 000 ml aluminium and atuminium alloys. and mix. The method is applicable to products having titanium contents between 0,005 and 0,3 % (m/m). 3.3 Nitric acid, p 1,40 g/ml, approximateiy 15 N solution. However, the method is not applicable completely to alloys having silicon contents greater than 1 % (m/m), for which it 3.4 Sulphuric acid, p 1,48 g/ml, approximately. 18 N must be modified as indicated in the annex. solution. Carefully add 500 mi of sulphuric acid, p 1,84 g/ml approximately 36 N solution, to approximately 400 ml of 2 PRINCIPLE water. After cooling, make up the volume to 1 000 ml and mix. Attack of a test portion with sodium hydroxide, and acidification of the alkaline solution with nitric acid and 3.5 Sulphuric acid, p 1,21 g/ml, approximately 7 N sulphuric acid. solution. Reduction of the iron(Ill) with ascorbic acid, and formation Carefully add 200 mi of sulphuric acid, p 1,84 g/ml, of the titanium-chromotropic acid complex at a chosen pH approximately 36 N solution, to approximately 700 ml of value between 2 and 2,50, controlled to within ± 0,05 pH water. After cuuling, make up the volume to 1 000 ml and unit. mix. Spectrophotometric measurement of the coloured complex at a wavelengh of about 470 nm. 3.6 Sulphuric acid, p 1,06 g/ml, approximately 2 N solution. Carefully add 60 ml of sulphuric acid, p 1,84 g/ml, approxi- 3 REAGENTS mately 36 N solution, to approximately 500 ml of water During the analysis, use only reagents of