7266 International Standard (ISO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION+MEXAYHAPOAHAA OPTAHM3AUMA NO CTAHAAPTM3ALWWORGANISATION INTERNATIONALE DE NORMALISATION Copper and copper alloys Determination of sulfur content Combustion titrimetric method Cuivre etalliagesdecuivre-Dosagedusoufre-Methodetitrimétriqueapres combustion First edition -- 1984-04-15 UDC 669.3 : 546.22 : 543.24 Ref. No. 1SO 7266-1984 (E) Descriptors : copper, copper alloys, chemical analysis, determination of content, suifur, volumetric analysis. Price based on 5 pages ed without license from IHS Not for Resale Foreword ISo (the Internationai Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of developing International interested in a subject for which a technical committee has been authorized 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. Internationa! Standard ISO 7266 was developed by Technicai Committee ISO/TC 26, Copper and copper alloys, and was circulated to the member bodies in February 1983. It has been approved by the member bodies of the following countries : Australia Italy Sweden Belgium Japan Switzerland Canada Korea, Dem. P. Rep. of Thailand Czechoslovakia Mexico Turkey Finland Netherlands USA France Poland USSR Germany, F.R. Romania Venezuela Hungary South Africa, Rep. of Iran No member body expressed disapproval of the document. ? International OrganizationforStandardization,1984 Printed in Switzerland Copyrightlinteatinal Organizatinfor Standardiation No reproduction or networking permitted without license from IHS Not for Resale INTERNATIONAL STANDARD ISO 7266-1984 (E) Copper and copper alloys - Determination of sulfur content - Combustion titrimetric method 1 Scope and field of application 4 Apparatus This International Standard specifies a combustion titrimetric Ordinary laboratory apparatus, and method for the determination of the sulfur content of copper and copper alloys. 4.1 Burette, 25 ml, with 0,05 ml graduations. The method is applicable to contents of sulfur greater than 0,010 % (m /m) in all types of copper and copper alloys listed in 4.2 Combustion apparatus (see figure 1), consisting of the International Standards. following : 4.2.1 Oxygen bottle with pressure regulatorand 2 Principle flowmeter (D). The oxygen must be sulfur-free. Combustion of a test portion in oxygen at 1 250 °C. Absorption 4.2.2 Purging tubes (A, and A2). A, is packed with asbestos of combustion gases in dilute hydrogen peroxide solution. treated with sodium hydroxide. The bottom part of A2 is fillied Titration of the sulfuric acid formed with sodium borate in the to three-quarters of its height with anhydrous magnesiumper presence of a mixed methyl red-methylene blue indicator chlorate; the top part is filled with phosphorus(V) oxide. The solution. two substances are separated by a plug of glass wool. 4.2.3 Two-way valve (R), with 3 to 4 mm tubing, such that Reagents oxygen can flow into the combustion tube T (4.2.6) and the 3 combustion gases can flow into the bubbler tube B (4.3.2). During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.2.4 Mercury check valve (S), with an equilibrium flask and a safety tube. The level of mercury is adjusted, by means of the equilibrium flask, so that a seal is made when, with valve R 3.1 Hydrogen peroxide, approximately 3 g/l solution. (4.2.3) open, the gas flows from the combustion tube at a rate of 2,5 t/min. When valve R is opened, an overpressure is Dilute 10 mt of hydrogen peroxide, 30 % (m /m) to 1 000 ml created, and the mercury seal operates until normal pressure is