ISO INTERNATIONAL STANDARD 4687-1 First edition 1992-04-15 Iron ores -- Determination of phosphorus content -- Part 1: Molybdenum blue spectrophotometric method Minerais de fer -Dosage du phosphore- Partie 1: Methode spectrophotometrique au bleu de molybdene Referencenumber ISO 4687-1:1992(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 4687-1:1992(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 body interested in a subject for which a technical committee has been established has the right to be represented on that committee. international organizations, govern- mental and non-governmentat, in liaison with iso, also take part in the work. Iso collaborates closely with the International Electrotechnical Commission(fEC)onallmattersofelectrotechnicalstandardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an tnter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard Iso 4687-1 was prepared by Technical Committee ISo/Tc 102, Iron ores, Sub-Committee SC 2, Chemical analysis. This first edition of iso 4687-1 cancels and replaces iso 4687:1984. which has been technically revised. Iso 4687 consists of the foliowing parts, under the general title Iron ores --Determination of phosphorus content: Part 1: Molybdenum blue spectrophotometric method The titrimetric content method will be covered in isO 4687-2 (at present ISO 2599:1983). Annex A forms an integraf part of this part of Iso 4687. Annexes B and Careforinformationonty. @ ISO 1992 All rights reserved. No part of this publlcatlon may be reproduced or utllized in any form or by any means, electronic or mechanical, Including photocopylng and microtilm, without permission inwritingfromthepubltsher. Internatlonal Organization for Standardizatlon Case Postale 56·CH-1211 Geneve 20· Switzerland Prlnted in Switzerland Standardizatior No reproduction or networking permtted without license from IHS Not for Resale ISO 4687-1:1992(E) INTERNATIONAL STANDARD Iron ores -- Determination of phosphorus content Part 1: Molybdenum blue spectrophotometric method 1 Scope Iso 7764:1985, lron ores -- Preparation of predried test samples for chemical analysis. ThispartofisO4687specifiesamolybdenumblue spectrophotometric method for the determination of Principle the phosphorus content of iron ores. This method is applicable to phosphorus contents Fusion of the test portion in sodium carbonate and between 0.003 % (m/m) and 2 % (m/m) in natural sodium tetraborate flux and dissolution of the cooled ironores,ironoreconcentratesandagglomerates, melt in hydrochloric acid. including sinter products. Treatment of an aliquot with sodium sulfite and The presence of arsenic, barium or titanium does perchioric acid followed by treatment of the not affect the result. phosphorus with molybdate and hydrazine sulfate to form a molybdenum blue complex. Spectrophotometric measurement of the molyb. 2 Normative references denum blue complex at an absorption peak wave- length of approximately 820 nm. The following standards contain provisions which, through reference in this text, constitute provisions of this part of iso 4687. At the time of publication, Reagents the editions indicated were valid. All standards are subject to revision, and parties to agreements based During the analysis, use only reagents of recognized on this part of Iso 4687 are encouraged to investi- analytical grade and oniy distilled water or water of gatethe possibilityof applyingthe mostrecent edi- tions of the standards indicated below. Members of equivalent purity. IEcandisOmaintainregistersofcurrentlyvalidIn- ternational Standards. 4.1 Sodium carbonate (Na