1、BRITISH STANDARD BSISO 13311:1997 Iron ores Determination of lead content Flame atomic absorption spectrometric method ICS 73.060.10BSISO13311:1997 This BritishStandard, having been prepared under the directionof the Engineering SectorBoard, was published underthe authority of the Standards Board an
2、d comes intoeffect on 15October1997 BSI03-2000 ISBN 0 580 28729 7 National foreword This BritishStandard reproduces verbatim ISO13311:1997 and implements it as the UK national standard. The UK participation in its preparation was entrusted by Technical Committee ISE/58, Iron ores, to Subcommittee IS
3、E/58/2, Analysis of iron ores, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UKinterests informed; monitor related international and Europea
4、n developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The BritishStandards which implement international or European publications referred to in this document may be found in the BSI Standa
5、rds Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible fo
6、r their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theISO title page, pages ii to iv, pages1 to8 and a back cover. This standard has be
7、en updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSISO13311:1997 BSI 03-2000 i Contents Page National foreword Inside front cover Foreword iii T
8、ext of ISO13311 1ii blankBS ISO 13311:1997 ii BSI 03-2000 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Apparatus 2 6 Sampling and samples 2 6.1 Laboratory sample 2 6.2 Preparation of predried test samples 2 7 Procedure 2 7.1 Number of determinations 2 7.
9、2 Test portion 2 7.3 Blank test and check test 2 7.4 Determination 3 7.4.1 Decomposition of the test portion 3 7.4.2 Treatment of residue 3 7.4.3 Treatment of combined filtrate and washings 3 7.4.4 Preparation of the set of lead calibration solutions 4 7.4.5 Adjustment of atomic absorption spectrome
10、ter 4 7.4.6 Atomic absorption measurements 4 8 Expression of results 4 8.1 Calculation of lead content 4 8.2 General treatment of results 4 8.2.1 Repeatability and permissible tolerance 4 8.2.2 Determination of analytical result 5 8.2.3 Between-laboratories precision 5 8.2.4 Check for trueness 5 8.2
11、.5 Calculation of final result 6 8.3 Oxide factor 6 9 Test report 6 Annex A (normative) Flowsheet of the procedure for the acceptance ofanalyticalvalues for test samples 7 Annex B (informative) Derivation of repeatability and permissible toleranceequations 7 Annex C (informative) Precision data obta
12、ined by international analytical trials 8 Figure C.1 Least-squares fit of precision against X for lead 8 Table 1 Dilution guide for test solution 3 Table 2 Calibration solutions 4 Table B.1 Lead content of test samples 7 Descriptors: Minerals and ores, metalliferous minerals, iron ores, chemical ana
13、lysis, determination of content, lead, atomic absorption spectrometric method.BS ISO 13311:1997 BSI 03-2000 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards
14、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, governmental and non-governmental, in liaison with ISO, also take pa
15、rt in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Stan
16、dard requires approval by at least75%of the member bodies casting a vote. International Standard ISO13311 was prepared by Technical Committee ISO/TC102, Iron ores, Subcommittee SC2, Chemical analysis. Together with ISO13310, it cancels and replaces ISO8753:1987, of which it constitutes a technical r
17、evision. Annex A forms an integral part of this International Standard. Annex B and Annex C are for information only.iv blankBS ISO 13311:1997 BSI 03-2000 1 WARNING This International Standard may involve hazardous materials, operations and equipment. This International Standard does not purport to
18、address all of the safety issues associated with its use. It is the responsibility of the user to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies a flame atomic absorption spectrom
19、etric method for the determination of the lead content of iron ores. This method is applicable to lead contents between0,001%(m/m) and0,5%(m/m) in natural iron ores, iron ore concentrates and agglomerates, including sinter products. 2 Normative references The following standards contain provisions w
20、hich, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibili
21、ty of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO648:1977, Laboratory glasswareOne-mark pipettes. ISO1042:1983, Laboratory glasswareOne-mark volumetric flasks. ISO3081:1986, Iron oresInc
22、rement sampling Manual method. ISO3082:1987, Iron oresIncrement sampling and sample preparationMechanical method. ISO3083:1986, Iron oresPreparation of samplesManual method. ISO3696:1987, Water for analytical laboratory useSpecification and test methods. ISO7764:1985, Iron oresPreparation of predrie
23、d test samples for chemical analysis. 3 Principle Decomposition of the test portion and removal ofsilica by treatment with hydrochloric acid and hydrofluoric acid. Oxidation with nitric acid. Evaporation to dryness, followed by dilution and filtration. Ignition of the residue. Fusion with sodium car
24、bonate. Dissolution of the cooled melt with hydrochloric acid. Reservation of the solution. Extraction of iron in the filtrate with 4-methyl-2-pentanone. Recovery of lead extracted. Decomposition of4-methyl-2-pentanone with nitric acid. Evaporation to dryness and dissolution of salts with the reserv
25、ed solution and hydrochloric acid. Aspiration of the solution into the flame of an atomic absorption spectrometer using an air-acetylene burner. Comparison of absorbance values obtained for lead with those obtained from the calibration solutions. 4 Reagents During the analysis, use only reagents of
26、recognized analytical grade and only water that complies with grade2 of ISO3696. 4.1 Sodium carbonate (Na 2 CO 3 ), anhydrous. 4.2 4-methyl-2-pentanone (MIBK), high purity. 4.3 Hydrochloric acid, 1,16g/ml to1,19g/ml. 4.4 Hydrochloric acid, 1,16g/ml to1,19g/ml, diluted10+6. 4.5 Hydrochloric acid, 1,1
27、6g/ml to1,19g/ml, diluted1+1. 4.6 Hydrochloric acid, 1,16g/ml to1,19g/ml, diluted2+98. 4.7 Nitric acid, 1,4g/ml. 4.8 Hydrofluoric acid, 1,13g/ml,40%(m/m), or 1,19g/ml,48%(m/m). 4.9 Lead standard solutions 4.9.1 Lead stock standard solution Dissolve1,000g of lead metal of purity99,5%(m/m) in40ml of n
28、itric acid ( 1,4g/ml, diluted1+1). Cool and dilute to1000ml in a one-mark volumetric flask and mix. 1ml of the stock solution contains10004g of lead. 4.9.2 Standard solution A Transfer10,0ml of lead stock standard solution(4.9.1) to a100ml volumetric flask. Dilute to volume and mix. 1ml of this stan
29、dard solution contains1004g of lead. 4.9.3 Standard solution B Transfer10,0ml of standard solution A(4.9.2) to a100ml volumetric flask. Dilute to volume and mix. 1ml of this standard solution contains1004g of lead.BS ISO 13311:1997 2 BSI 03-2000 5 Apparatus Ordinary laboratory apparatus, including o
30、ne-mark pipettes and one-mark volumetric flasks complying with the specifications of ISO648 and ISO1042 respectively, and 5.1 Polytetrafluoroethylene (PTFE) beaker, of capacity250ml, with a PTFE cover. 5.2 Atomic absorption spectrometer, equipped with an air-acetylene burner. The atomic absorption s
31、pectrometer shall meet the following criteria. WARNING Follow the manufacturers instructions for igniting and extinguishing the air-acetylene flame to avoid possible explosion hazards. Wear tinted safety glasses whenever the burner is in operation. a) Minimum sensitivitythe absorbance of the most co
32、ncentrated calibration solution (see7.4.4) shall be at least0,25. b) Graph linearitythe slope of the calibration graph covering the top20%of the concentration range (expressed as a change in absorbance) shall not be less than0,7 of the value of the slope for the bottom20%of the concentration range d
33、etermined in the same way. c) Minimum stabilitythe standard deviation ofthe absorbance of the most concentrated calibration solution and that of the zero calibration solution, each being calculated from asufficient number of repetitive measurements, shall be less than1,5%and0,5%respectively ofthe me
34、an value of the absorbance of the most concentrated calibration solution. NOTE 1The use of a strip-chart recorder and/or digital readout device is recommended to evaluate criteriaa),b) andc) and for all subsequent measurements. NOTE 2Instrument parameters will vary with each instrument. The followin
35、g parameters were successfully used inseveral laboratories and they can be used as guidelines. In systems where the values shown for gas flow rates do not apply, the ratio of the gas flow rates may still be a useful guideline. 6 Sampling and samples 6.1 Laboratory sample For analysis, use a laborato
36、ry sample of minus1004m particle size which has been taken in accordance with ISO3081 or ISO3082 and prepared in accordance with ISO3082 or ISO3083. In the case of ores having significant contents of combined water or oxidizable compounds, use a particle size of minus1604m. NOTEA guideline on signif
37、icant contents of combined water and oxidizable compounds is incorporated in ISO7764. 6.2 Preparation of predried test samples Thoroughly mix the laboratory sample and, taking multiple increments, extract a test sample in such a manner that it is representative of the whole contents of the container
38、. Dry the test samples at105 C 2 C as specified in ISO7764. (This is the predried test sample.) 7 Procedure 7.1 Number of determinations Carry out the analysis at least in duplicate in accordance with Annex A, independently, on one predried test sample. NOTEThe expression “independently” means that
39、the second and any subsequent result is not affected by the previous result(s). For this particular analytical method, this condition implies that the repetition of the procedure is carried out either by the same operator at a different time or by a different operator including, in either case, appr
40、opriate recalibration. 7.2 Test portion Taking several increments, weigh, to the nearest0,0002g, approximately2g of the predried test sample obtained in accordance with6.2. NOTEThe test portion should be taken and weighed quickly in order to avoid reabsorption of moisture. 7.3 Blank test and check t
41、est In each run, one blank test and one analysis of a certified reference material of the same type of ore shall be carried out in parallel with the analysis of the ore sample(s) under the same conditions. A predried test sample of the certified reference material shall be prepared as specified in6.
42、2. NOTEThe certified reference material should be of the same type as the sample to be analysed and the properties of the two materials should be sufficiently similar to ensure that, in either case, no significant changes in the analytical procedure become necessary. Hollow cathode lamp, mA 6 Wavele
43、ngth, nm 283,3 Air flow rate, l/min 14 Acetylene flow rate, l/min 3BS ISO 13311:1997 BSI 03-2000 3 When the analysis is carried out on several samples at the same time, the blank value may be represented by one test, provided that the procedure is the same and the reagents are from the same reagent
44、bottles. When the analysis is carried out on several samples of the same type of ore at the same time, the analytical value of one certified reference material may be used. 7.4 Determination 7.4.1 Decomposition of the test portion Transfer the test portion(7.2) to a250ml PTFE beaker(5.1). Moisten wi
45、th a few millilitres of water, add40ml of hydrochloric acid(4.3) and10ml of hydrofluoric acid(4.8), and cover with a PTFE cover. Heat on a hotplate at100 C, then increase the heat to200 C. Evaporate to dryness. Add5ml of nitric acid(4.7) and evaporate to nearly1ml. Dissolve the salts with10ml of hyd
46、rochloric acid(4.3) and evaporate to dryness again. Dissolve the salts with5ml of hydrochloric acid(4.3). Add10ml of water and filter through a close-texture paper into a250ml beaker. Remove all adhering particles from the beaker with a rubber-tipped rod, wash with hydrochloric acid(4.6) until the p
47、aper is free from iron stains, and wash the paper three times with hot water. Reserve the residue and combined filtrate and washings. 7.4.2 Treatment of residue Place the paper and residue in a platinum crucible, dry and char the paper at a low temperature and ignite in a muffle furnace at550 C. Add
48、0,5g of sodium carbonate(4.1) and fuse over a Bunsen burner (about900 C to1000 C) until a clear melt is obtained. Dissolve the cooled melt with5ml of hydrochloric acid(4.5), heat to remove carbon dioxide and reserve the solution. 7.4.3 Treatment of combined filtrate and washings Evaporate the filtra
49、te and washings(7.4.1) just todryness. Dissolve the salts with20ml of hydrochloric acid(4.4), and transfer to a200ml separating funnel. Rinse the beaker with20ml ofhydrochloric acid(4.4) and combine these washings with the main solution. Add50ml of 4-methyl-2-pentanone(4.2) and shake thoroughly for1min. Allow the layers to separate, then run the lower aqueous solution into a250ml beaker. Wash the organic phase by extracting with10ml of hydrochloric acid(4.4), and transfer the washings tothe beaker. Heat the solutio
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