1、 Reference number ISO 9682-2:2006(E) ISO 2006INTERNATIONAL 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 periodate ISO 9682-2:2006(E) PDF
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6、y of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2006 All rights reservedISO 9682-2:2006(E) ISO 2006 All rights reserved iii Contents Page Foreword iv 1 Scop
7、e. 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 . 4 7.3 Blank test and check test. 4 7.4 Calibration. 4 7.4.1 Sample
8、s 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 solution . 6 7.5.4 Spectrophotometric measurements . 6 8 Expression of
9、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 Check for trueness . 9 8.2.5 Calculation of final results. 9 8.3 Oxid
10、e 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 (informative) Precision data obtained by international analytical trials
11、. 13 ISO 9682-2:2006(E) iv ISO 2006 All rights reservedForeword 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.
12、 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 collaborates closely with the Interna
13、tional 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 International Standards. Draft International Stan
14、dards 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 elements of this document may be the subje
15、ct 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 9682-2 cancels and replaces ISO 3886:1986
16、, 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 spectrometric method Part 2: Periodate
17、spectrophotometric method INTERNATIONAL STANDARD ISO 9682-2:2006(E) ISO 2006 All rights reserved 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 d
18、oes not purport 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 spec
19、ifies a spectrophotometric 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.
20、 2 Normative references 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 glass
21、ware One-mark pipettes 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
22、3 Principle A test 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 trea
23、tment with hydrofluoric 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. ISO 9682-2:2006(E) 2 ISO 2006 All rights reserved
24、The absorbance due to the permanganate ion is 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.
25、1) shall be used for the spectrophotometric 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 per
26、oxide should be kept away from humidity and 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, 6
27、0 % (by mass) ( 1,54 g/ml) or 70 % (by mass) ( 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 p
28、our 100 ml of sulfuric acid ( 1,84 g/ml) into 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 solu
29、tions. 4.15.1 Stock solution Dissolve 0,500 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 volume
30、tric flask, dilute to the mark with water and mix. 1 ml of stock solution contains 1,00 mg of manganese. ISO 9682-2:2006(E) ISO 2006 All rights reserved 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 co
31、ntains 0,100 mg of manganese. 4.15.3 Standard solution B Take 250 ml of standard 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 flas
32、ks complying with the specifications of ISO 648 and ISO 1042, and the following. 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
33、 sample For analysis, use a laboratory sample of minus 100 m particle size 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 con
34、tents of combined water and oxidizable compounds is incorporated in ISO 7764. 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 th
35、e test sample at 105 2C as specified in ISO 7764. (This is the predried test 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 a
36、ccordance with Annex A, independently, on one predried test sample. NOTE 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 car
37、ried out either by the same operator at a different time or by a different operator, including, in either case, appropriate recalibration. ISO 9682-2:2006(E) 4 ISO 2006 All rights reserved7.2 Test portion Taking several increments, weigh, to the nearest 0,000 2 g, approximately 1 g of the predried t
38、est sample obtained in accordance with 6.2. The test portion should be taken and weighed quickly in order 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 pa
39、rallel 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 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
40、should be sufficiently similar to ensure that, in either case, no significant changes in the analytical 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 s
41、ame time, the blank value may be represented by one test, provided that the procedure is the same and 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 ma
42、terial may be used. 7.4 Calibration 7.4.1 Samples containing more than 0,1 % (by mass) of manganese 7.4.1.1 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
43、 A (4.15.2). Add 30 ml of sulfuric acid/phosphoric acid mixture (4.12), and dilute to about 60 ml with 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 dev
44、elopment of the permanganate ion. Cool each solution, transfer to a series of five 100 ml volumetric flasks, 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 s
45、olution A. 7.4.1.3 Spectrophotometric measurements Transfer a part of each solution (7.4.1.1) to a spectrophotometric 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 absorb
46、ance near 535 nm, after having adjusted the instrument to zero absorbance against the calibration compensation 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 perm
47、anganate ion; transfer a part of each solution to the corresponding spectrophotometric cell, and measure 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. ISO 9682-2:2006(E) ISO 2006 All
48、rights reserved 5 The measurement of absorbance should not be postponed unduly after decoloration of the pink colour of the permanganate 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 showin
49、g the differences between the absorbances, A i1 A i2 , of the set of calibration solutions as a function of the quantities of manganese 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 below 0,1 %, the heating time should be approximately 30 min and,
