1、BRITISH STANDARD BS ISO 9682-2:2006 Iron ores Determination of manganese content Part 2: Periodate spectrophotometric method ICS 73.060.10 BS ISO 9682-2:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2007 BSI 2007 ISBN 978 0
2、580 50114 2 National foreword This British Standard was published by BSI. It is the UK implementation of ISO 9682-2:2006. It supersedes BS 7020-9-1:1988 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ISE/58, Iron ores. A list of organizations represe
3、nted on ISE/58 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued
4、since publication Amd. No. Date Comments Reference number ISO 9682-2:2006(E)INTERNATIONAL STANDARD ISO 9682-2 First edition 2006-12-01 Iron ores Determination of manganese content Part 2: Periodate spectrophotometric method Minerais de fer Dosage du manganse Partie 2: Mthode spectrophotomtrique au p
5、eriodate BS ISO 9682-2:2006ii iii Contents Page Foreword iv 1 Scope. 1 2 Normative references. 1 3 Principle. 1 4 Reagents 2 5 Apparatus 3 6 Sampling and samples. 3 6.1 Laboratory sample 3 6.2 Preparation of predried test samples . 3 7 Procedure 3 7.1 Number of determinations . 3 7.2 Test portion .
6、4 7.3 Blank test and check test. 4 7.4 Calibration. 4 7.4.1 Samples containing more than 0,1 % (by mass) of manganese 4 7.4.2 Samples containing less than 0,1 % manganese5 7.5 Determination 5 7.5.1 Decomposition of the test portion 5 7.5.2 Treatment of the residue 6 7.5.3 Treatment of the test solut
7、ion . 6 7.5.4 Spectrophotometric measurements . 6 8 Expression of results. 7 8.1 Calculation of mass fraction of manganese 7 8.2 General treatment of results 8 8.2.1 Repeatability and permissible tolerance 8 8.2.2 Determination of analytical result. 8 8.2.3 Between-laboratories precision 8 8.2.4 Che
8、ck for trueness . 9 8.2.5 Calculation of final results. 9 8.3 Oxide factor. 10 9 Test report. 10 Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for test samples 11 Annex B (informative) Derivation of repeatability and permissible tolerance . 12 Annex C (inform
9、ative) Precision data obtained by international analytical trials . 13 BS ISO 9682-2:2006iv 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
10、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 part in the work. ISO
11、collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare Internationa
12、l Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the eleme
13、nts of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 9682-2 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis. This first edition of ISO 9682
14、-2 cancels and replaces ISO 3886:1986, which has been technically revised. It has been updated to alter the manner in which precision data are presented. ISO 9682 consists of the following parts, under the general title Iron ores Determination of manganese content: Part 1: Flame atomic absorption sp
15、ectrometric method Part 2: Periodate spectrophotometric method BS ISO 9682-2:2006 1 Iron ores Determination of manganese content Part 2: Periodate spectrophotometric method WARNING This part of ISO 9682 may involve hazardous materials, operations and equipment. This part of ISO 9682 does not purport
16、 to address all of the safety problems associated with its use. It is the responsibility of the user of this part of ISO 9682 to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to use. 1 Scope This part of ISO 9682 specifies a spectro
17、photometric method using sodium periodate for the determination of the mass fraction of manganese in iron ores. This method is applicable to a mass-fraction range of 0,02 % to 8 % of manganese in natural iron ores, and iron ore concentrates and agglomerates, including sinter products. 2 Normative re
18、ferences The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 648, Laboratory glassware One-mark p
19、ipettes ISO 1042, Laboratory glassware One-mark volumetric flasks ISO 3082, Iron ores Sampling and sample preparation procedures ISO 3696, Water for analytical laboratory use Specification and test methods ISO 7764, Iron ores Preparation of predried test samples for chemical analysis 3 Principle A t
20、est portion is decomposed by one of the following methods: a) treatment with hydrochloric, nitric and perchloric acids; b) sintering with sodium peroxide, followed by treatment with hydrochloric and perchloric acids. The mixture is filtered and the residue is ignited, followed by treatment with hydr
21、ofluoric and sulfuric acids, and fusion with sodium carbonate. The cooled melt is dissolved in the main solution. Managanese in an aliquot is oxidized to permanganate ion, using sodium periodate in sulfuric acid/phosphoric acid medium. BS ISO 9682-2:20062 The absorbance due to the permanganate ion i
22、s measured spectrophotometrically at a wavelength of about 535 nm. 4 Reagents During the analysis, use only reagents of recognized analytical grade, and only water that conforms to grade 2 of ISO 3696 except that water which is free from organic matter (4.1) shall be used for the spectrophotometric
23、measurement. 4.1 Water, free from organic matter. Add 20 ml of sulfuric acid (4.9) to 1 litre of water, bring to the boil, add several crystals of sodium periodate, continue boiling for 10 min, then cool. 4.2 Sodium peroxide (Na 2 O 2 ), powder. Sodium peroxide should be kept away from humidity and
24、should not be used once it has begun to agglomerate. 4.3 Sodium carbonate (Na 2 CO 3 ), anhydrous. 4.4 Hydrochloric acid, 1,16 g/ml to 1,19 g/ml. 4.5 Hydrochloric acid, 1,16 g/ml to 1,19 g/ml, dilute 1 + 9. 4.6 Nitric acid, 1,4 g/ml. 4.7 Perchloric acid, 60 % (by mass) ( 1,54 g/ml) or 70 % (by mass)
25、 ( 1,67 g/ml). 4.8 Hydrogen peroxide, 3 % (by volume). 4.9 Sulfuric acid, 1,84 g/ml, diluted 1 + 1. 4.10 Sulfuric acid, 1,84 g/ml, diluted 1 + 100. 4.11 Hydrofluoric acid, 40 % (by mass) ( 1,13 g/ml). 4.12 Sulfuric acid/phosphoric acid mixture. Carefully pour 100 ml of sulfuric acid ( 1,84 g/ml) int
26、o about 600 ml of water while stirring, cool, add 150 ml of phosphoric acid ( 1,70 g/ml) and dilute to 1 000 ml with water. 4.13 Sodium periodate (NalO 4 ) solution, 50 g/l. 4.14 Sodium nitrite (NaNO 2 ) solution, 10 g/100 ml. 4.15 Manganese, standard solutions. 4.15.1 Stock solution Dissolve 0,500
27、g of pure metallic manganese in 20 ml of nitric acid (4.6), add 20 ml of sulfuric acid (4.9) and heat to dense white fumes for about 10 min to expel all oxides of nitrogen. Cool, add about 100 ml of water to dissolve the salt, transfer into a 500 ml volumetric flask, dilute to the mark with water an
28、d mix. 1 ml of stock solution contains 1,00 mg of manganese. BS ISO 9682-2:2006 3 4.15.2 Standard solution A Take 100 ml of stock solution (4.15.1) and dilute to 1 000 ml in a volumetric flask. 1 ml of this standard solution contains 0,100 mg of manganese. 4.15.3 Standard solution B Take 250 ml of s
29、tandard solution A (4.15.2) and dilute to 1 000 ml in a volumetric flask. 1 ml of this standard solution contains 0,025 mg of manganese. 5 Apparatus Ordinary laboratory equipment, including one-mark pipettes and volumetric flasks complying with the specifications of ISO 648 and ISO 1042, and the fol
30、lowing. 5.1 Spectrophotometer, suitable for the measurement of absorbance at approximately 535 nm. 5.2 Nickel crucible, free of manganese. 5.3 Pletinum crucible, of capacity 25 ml to 30 ml. 6 Sampling and samples 6.1 Laboratory sample For analysis, use a laboratory sample of minus 100 m particle siz
31、e which has been taken and prepared in accordance with ISO 3082. In the case of ores having significant contents of combined water or oxidizable compounds, use a particle size of minus 160 m. NOTE A guideline on significant contents of combined water and oxidizable compounds is incorporated in ISO 7
32、764. 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. Dry the test sample at 105 2C as specified in ISO 7764. (This is the predried t
33、est sample.) 7 Procedure WARNING Perchloric acid vapour may cause explosions in the presence of ammonia, nitrous fumes or organic matter in general. 7.1 Number of determinations Carry out the analysis at least in duplicate in accordance with Annex A, independently, on one predried test sample. NOTE
34、The expression “independently” means that 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 differen
35、t operator, including, in either case, appropriate recalibration. BS ISO 9682-2:20064 7.2 Test portion Taking several increments, weigh, to the nearest 0,000 2 g, approximately 1 g of the predried test sample obtained in accordance with 6.2. The test portion should be taken and weighed quickly in or
36、der to avoid reabsorption of moisture. 7.3 Blank test and check test 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
37、 certified reference material shall be prepared as specified in 6.2. The 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 analytica
38、l procedure would become necessary. Where a certified reference material is not available, a reference material may be used (see 8.2.4). Where 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
39、the reagents used are from the same reagent bottles. Where 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 Calibration 7.4.1 Samples containing more than 0,1 % (by mass) of manganese 7.
40、4.1.1 Set of calibration solutions and formation of the absorbing compound Into a series of five 300 ml beakers, introduce 2,0 ml; 5,0 ml; 10,0 ml; 15,0 ml and 20,0 ml of manganese standard solution A (4.15.2). Add 30 ml of sulfuric acid/phosphoric acid mixture (4.12), and dilute to about 60 ml with
41、 water (4.1). Add 10 ml of sodium periodate solution (4.13) to each solution, cover each beaker with a watch-glass, heat to boiling, and maintain just below boiling point for 10 min after colour development of the permanganate ion. Cool each solution, transfer to a series of five 100 ml volumetric f
42、lasks, make up to the mark with water (4.1) and mix. 7.4.1.2 Calibration compensation solution Prepare a calibration compensation solution according to 7.4.1.1, but omitting the manganese standard solution A. 7.4.1.3 Spectrophotometric measurements Transfer a part of each solution (7.4.1.1) to a spe
43、ctrophotometric cell of suitable thickness, and measure the absorbance of each, A i1 , where i is 1 to 5 cm optical path length, with the spectrophotometer (5.1), at the wavelength of maximum absorbance near 535 nm, after having adjusted the instrument to zero absorbance against the calibration comp
44、ensation solution (7.4.1.2). Add sodium nitrite solution (4.14), drop by drop, to the solutions in the volumetric flasks, while mixing, until 1 drop in excess decolorizes the pink colour of the permanganate ion; transfer a part of each solution to the corresponding spectrophotometric cell, and measu
45、re the absorbances, A i2 , as described in the first paragraph. NOTE An increase in the volume of the solution by addition of sodium nitrite solution is disregarded. BS ISO 9682-2:2006 5 The measurement of absorbance should not be postponed unduly after decoloration of the pink colour of the permang
46、anate ion by sodium nitrite solution, because reoxidation of the manganese ion occurs on standing. 7.4.1.4 Plotting the calibration graph Plot a calibration graph showing the differences between the absorbances, A i1 A i2 , of the set of calibration solutions as a function of the quantities of manga
47、nese contained in these solutions. 7.4.2 Samples containing less than 0,1 % manganese 7.4.2.1 Set of calibration solutions and formation of the absorbing compound As in 7.4.1.1, but using manganese standard solution B (4.15.3) instead of manganese standard solution A. For mass fractions of manganese
48、 below 0,1 %, the heating time should be approximately 30 min and, if necessary, water (4.1) should be added to maintain the volume. 7.4.2.2 Calibration compensation solution Prepare a calibration compensation solution according to 7.4.2.1, but omitting the manganese standard solution B. 7.4.2.3 Spe
49、ctrophotometric measurements Proceed as in 7.4.1.3, but using the solutions from 7.4.2.1. 7.4.2.4 Plotting the calibration graph See 7.4.1.4. 7.5 Determination 7.5.1 Decomposition of the test portion If the decomposition is to be based on acid attack, proceed as instructed in 7.5.1.1. If the decomposition is to be based on alkali sintering, proceed as instructed in 7.5.1.2. 7.5.1.1 Acid attack Place the test portion (7.2) in a 300 ml beake
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