ISO INTERNATIONAL STANDARD 4295 Second edition 1988-06-01 INTERNATIONALORGANIZATIONFORSTANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEKAYHAPOAHAAOPIAHM3ALMROCTAHAAPTM3AMM Manganese ores and concentrates - Determination of aluminium content - Photometric and gravimetric methods Minerais et concentrés de manganese --- Dosage de I'aluminium - Methodes photometrique etgravimetrique Referencenumber [SO 4295 : 1988 (E) Copyright Int ernational Organization for Standardization Noreproductionornetworkingpermitedwithout licensefromHS Not for Resale ISO 4295:1988 (E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through Iso technical committees. Each member bodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhas the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with IsO, also take part in the work. IsO collaborates closely with the International Electrotechnical Commission (IEC) on all mattersof electrotechnicalstandardization. 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. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 4295 was prepared by Technical Committee ISO/TC 65, Manganese and chromium ores. Thissecondeditioncancelsandreplacesthefirstedition(lSO4195:1979),ofwhichit constitutes atechnicalrevision. Users shouldnotethat all International Standards undergo revision from timeto time and that any reference made herein to any other International Standard implies its latestedition,unlessotherwisestated ? International Organization for Standardization, 1988 Printed in Switzerland yghmainalOganizatiandardiza No reproduction or networking permited without license from IHS Not for Resale ISO4295:1988 (E) INTERNATIONALSTANDARD Manganese ores and concentrates - Determination of aluminium content - Photometric and gravimetric methods Scope and field of application Photometric determination in the presence of ascorbic acid and polyvinyl alcohol. This International Standard specifies the following methods for the determination of the aluminium content of manganese ores 3.2 Reactions and concentrates: The method is based on the interaction of aluminium with method A : photometric method, applicable to prod- chromazurol-s in the presence of polyvinyl aicohol in acetate ucts having aluminium contents from 0,1 to 1,5 % (m/m); buffersolution(pH6-7)withtheformationofacolouredcom plex between the aluminium and chromazurol-s with a method B : oxine gravimetric method, applicable to molecularratio1:3.The influenceof iron(l)iseliminatedby products having aluminium contents over 1,5 % (m/m). precipitation with an alkaline borate mixture which prevents It should be read in conjunction with Iso 4297. sorption of aluminium by the hydroxides. 3.3 Reagents 2 References Use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. Iso 4296-1, Manganese ores - Sampling - Part 1: In- crement sampling. 3.3.1 Ammonium acetate (CH3CoONH4). Iso 4296-2, Manganese ores - Sampling - Part 2: Prep- aration of samples. 3.3.2 Boric acid. Iso 4297, Manganese ores and concentrates -- Methods of 3.3.3 Sodium tetraborate, anhydrous (Na2B407). chemicalanalysis-General instructions. 3.3.4 Sodium carbonate, anhydrous. 3 Method A -- Photometric method for 3.3.5 Sodium acetate trihydrate (CH3COONa.3H2O). aluminium contents from 0,1 to 1,5 % (m/m) 3.3.6 Fusion mixture : three parts of sodium carbonate 3.1 Principle (3.3.4) and one part of sodium tetraborate (3.3.3). Decomposition of a test portion by treatment with hydrochloric and nitric acids a