1、BRITISH STANDARD BS EN ISO 11489:1995 Determination of platinum in platinum jewellery alloys Gravimetric method after reduction with mercury(I) chloride The European Standard EN ISO11489:1995 has the status of a British StandardBSENISO11489:1995 This British Standard, having been prepared under the
2、directionof the Sector Board forMaterials and Chemicals, waspublished under the authorityof the Standards Boardand comes into effect on 15 September1995 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference STI/53 Draft for comment 92/36607 DC ISBN 0 580 2
3、4653 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee STI/53, Jewellery, upon which the following bodies were represented; Birmingham Assay Office British College of Optometrists British Horological Federation British Ho
4、rological Institute British Jewellers Association British Jewellery and Giftware Federation British Retail Consortium Department of Trade and Industry (Laboratory of the Government Chemist) Federation of Manufacturing Opticians Joint Committee of Assay Offices of Great Britain Mail Order Traders Ass
5、ociation National Association of Goldsmiths of Great Britain and Ireland Nickel Development Institute Sheffield Assay Office Amendments issued since publication Amd. No. Date CommentsBSENISO11489:1995 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword
6、 2 1 Scope 3 2 Normative reference 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Sampling 3 7 Procedure 4 8 Expression of results 4 9 Test report 5 Annex A (informative) Reduction apparatus according to Rose 6 Figure A.1 Reduction apparatus 6BSENISO11489:1995 ii BSI 11-1999 National foreword This Bri
7、tish Standard has been prepared by Technical Committee STI/53 and is the English language version of ENISO11489:1995 Determination of platinum in platinum jewellery alloys Gravimetric method after reduction with mercury(I) chloride published by the European Committee for Standardization (CEN). It is
8、 identical with ISO11489:1995 published by the International Organization for Standardization (ISO). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard
9、 does not of itself confer immunity from legal obligations. Cross-reference Publication referred to Corresponding British Standard ISO 9202:1991 BS EN 29202:1993 Jewellery Fineness of precious metal alloys Summary of pages This document comprises a front cover, an inside front cover, pages i and ii,
10、 theEN ISO title page, pages 2 to 6 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 11489 May 1995 ICS 39.0
11、60 Descriptors: Platinum alloys, chemical analysis, determination of content, platinum, gravimetric analysis English version Determination of platinum in platinum jewellery alloys Gravimetric method after reduction with mercury(I) chloride (ISO11489:1995) Dosage de platine dans les alliages de plati
12、ne pour la bijouterie-joaillerie Mthode gravimtrique aprs rduction au chloride de mercure(I) (ISO 11489:1995) Bestimmung von Platin in Platin-Schmucklegierungen Gravimetrische Bestimmung durch Reduktion mit Quecksilber(I)-Chlorid (ISO11489:1995) This European Standard was approved by CEN on 1995-04-
13、27. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained
14、on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretari
15、at has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for
16、 Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members Ref. No. EN ISO 11489:1995 EENISO114
17、89:1995 BSI 11-1999 2 Foreword The text of the International Standard ISO11489:1995 has been prepared by Technical Committee ISO/TC174, Jewellery, in collaboration with CEN/TC283, Precious metals Applications in jewellery and associated products. It has been submitted to parallel vote and was approv
18、ed by CEN on 1995-04-27 as a European Standard. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November1995, and conflicting national standards shall be withdrawn at the latest by November1995. A
19、ccording to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.
20、ENISO11489:1995 BSI 11-1999 3 1 Scope This International Standard specifies a gravimetric method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness stated in ISO9202. The procedure applies specifically to platinum alloys incorporating palladium, i
21、ridium, rhodium, copper, cobalt, gold, ruthenium, gallium, chromium, indium and less than5% tungsten. Some modifications are indicated where palladium, iridium, rhodium, gold or ruthenium are present. 2 Normative reference The following standard contains provisions which, through reference in this t
22、ext, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edit
23、ion of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 9202:1991, Jewellery Fineness of precious metal alloys. 3 Principle The sample is dissolved in aqua regia. After elimination of all nitrates by evaporation, the residue is d
24、issolved in hydrochloric acid. The platinum is then precipitated from this solution by reduction with mercury(I) chloride. The mercury is eliminated by ignition and the platinum is weighed. If present, gold and palladium will also be precipitated by this reduction procedure. Their content shall be d
25、etermined separately by, for example, atomic absorption or inductively coupled plasma (ICP) emission spectrometry, and a correction applied. 4 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purit
26、y. 4.1 Hydrochloric acid, 36% (m/m) to38% (m/m), 20 =1,19g/cm 3 . 4.2 Dilute hydrochloric acid, 18% (m/m), 20 =1,09g/cm 3 . 4.3 Dilute hydrochloric acid, 8,5% (m/m), 20 =1,04g/cm 3 . 4.4 Nitric acid, 69% (m/m), 20 =1,41g/cm 3 . 4.5 Mercury(I) chloride (Hg 2 Cl 2 ), in suspension. Dissolve200g of mer
27、cury(I) nitrate dihydrate Hg 2 (NO 3 ) 2 2H 2 O in300ml of water in a beaker and add approximately50ml of nitric acid; just sufficient to ensure that the basic mercury(I) nitrate is redissolved. Dilute the solution with water to4litres and add400ml of cold saturated ammonium chloride solution. Allow
28、 the precipitate of mercury(I) chloride to settle, decant and wash about20times to ensure that it is nitrate free. Add2litres of water and store in a closed flask. NOTE 1This suspension is stable and can be used even after storage for a few months. 4.6 Hydrofluoric acid, 40% (m/m), 20 =1,13g/cm 3 .
29、4.7 Dilute sulfuric acid, 50% (m/m), 20 =1,42g/cm 3 . 4.8 Reducing gas, such as hydrogen or a hydrogen/nitrogen mixture. 4.9 Inert gas, such as carbon dioxide or nitrogen. 4.10 Aqua regia Mix3 volumes of hydrochloric acid(4.1) and1 volume of nitric acid(4.4). WARNING Aqua regia is potentially hazard
30、ous and safety glasses or goggles must be used. Dissolution should be carried out in a well-ventilated fume cupboard. 5 Apparatus Ordinary laboratory apparatus and 5.1 Reduction apparatus, seeFigure A.1 in Annex A. 5.2 Platinum dishes, of volume10ml. 5.3 Atomic absorption or inductively coupled plas
31、ma (ICP) emission spectrometer, or other means of determining traces of metals. 5.4 Muffle furnace, capable of attaining at least900 C. 5.5 Ashless filter paper, capable of retaining34m particles. 6 Sampling The sampling procedure for platinum jewellery alloys shall be agreed upon until a correspond
32、ing standard method has been published.ENISO11489:1995 4 BSI 11-1999 7 Procedure 7.1 Platinum jewellery alloys with not more than5% iridium, rhodium or ruthenium Weigh the sample containing approximately250mg to300mg of platinum, accurately to the nearest0,01mg, and transfer it to a glass beaker. Di
33、ssolve the sample in20ml of aqua regia (4.10) in the glass beaker covered with a watch glass, while heating gently. Any insoluble material remaining after this procedure shall be filtered off at this stage and its composition established for possible correction of the results. Heat the solution on a
34、 hotplate and evaporate almost to dryness. Dissolve the still moist salt residue in10ml of dilute hydrochloric acid (4.2) and evaporate almost to dryness again. Repeat this dissolution in hydrochloric acid and evaporation three times, finally dissolving the residue in10ml of dilute hydrochloric acid
35、 (4.2), and then diluting the solution with hot water to a total volume of300ml. Heat the solution to boiling and, while continuing to boil, add the shaken mercury(I) chloride suspension in portions of5ml to10ml. Continue to add the suspension until the initially black precipitate turns grey due to
36、excess addition. Allow the precipitate to settle for about15min at a temperature above85 C and filter through a double filter paper(5.5). Wash the precipitate and beaker thoroughly with dilute hydrochloric acid(4.3). Retain the filtrate for testing for platinum by suitable means and, if detected, a
37、correction shall be applied. Fold the filter paper containing the precipitate, place it in a preweighed glazed porcelain crucible and dry at120 C under flowing air. Gradually increase the temperature to400 C over approximately30min. It is important to control the rate of heating to400 C, as rapid me
38、rcury distillation can cause losses of platinum. Once a temperatureof400 C is achieved, the crucible and contents can be heated at900 C for60min in a muffle furnace(5.4) to ignite the precipitate. WARNING Considering the health hazards associated with mercury vapour, it must be ensured that all appr
39、opriate precautions are taken to prevent it entering the atmosphere. Cool the crucible which now contains the platinum sponge. The sponge absorbs oxygen if palladium is present, so heat it with reducing gas(4.8) in a reduction apparatus(5.1) and cool under an inert atmosphere(4.9). A check weighing
40、can be made at this stage to confirm that the platinum content approximates that expected. Transfer the sponge to a platinum dish and purify it by moistening with a little hydrofluoric acid(4.6) and three drops of dilute sulfuric acid(4.7). Heat until fuming commences and then cool, add a little hot
41、 water, filter and wash with hot dilute hydrochloric acid (4.3). Ash the filter and sponge in a porcelain crucible and ignite at700 C in a muffle furnace(5.4). The sponge should then be treated again in the reduction apparatus(5.1) and cooled under an inert atmosphere (4.9) before finally weighing.
42、Any gold and palladium in the sponge is then determined by suitable means, such as atomic absorption or ICP emission spectrometry (5.3) and a correction applied. It is also possible that iridium, rhodium and ruthenium may still be present in the final sponge. It is recommended that the sponge be che
43、cked for the presence of these elements by suitable means, such as atomic absorption or ICP emission spectrometry. If they are detected, a correction shall be applied. 7.2 Platinum jewellery alloys with more than5% iridium, rhodium or ruthenium Follow the procedure described in7.1. However, for diss
44、olving use a pressure dissolution procedure. 8 Expression of results 8.1 Method of calculation 8.1.1 If the final weighed mass contains exclusively platinum, calculate the platinum content w pt , in parts by mass per thousand(), using the formula 8.1.2 If the final weighed mass contains other elemen
45、ts, calculate the platinum content w pt , in parts by mass per thousand (), using the formula where m Xis the total mass, in milligrams, of other elements. where m 1 is the mass, in milligrams, of the sample; m 2 is the mass, in milligrams, of the filtrate; m 3 is the final mass, in milligrams.ENISO
46、11489:1995 BSI 11-1999 5 8.2 Repeatability The results of duplicate determinations shall correspond to better than3parts per mass per thousand () of platinum. If the variation is greater than this, the assays shall be repeated. 9 Test report The test report shall include the following information: a
47、) identification of the sample including source, date of receipt, form of sample; b) sampling procedure; c) the method used by reference to this International Standard; d) platinum content of the sample, in parts by mass per thousand () as single values and mean values; e) if relevant, any deviation
48、s from the method specified in this International Standard; f) any unusual features observed during the determination; g) date of test; h) identification of the laboratory carrying out this analysis; i) signature of the laboratory manager and operator.ENISO11489:1995 6 BSI 11-1999 Annex A (informati
49、ve) Reduction apparatus according to Rose Figure A.1 Reduction apparatusblankBS EN ISO 11489:1995 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or ed
