1、BRITISH STANDARD BS ISO 9683-1:2006 Iron ores Determination of vanadium Part 1: BPHA spectrophotometric method ICS 73.060.10 BS ISO 9683-1:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2007 BSI 2007 ISBN 978 0 580 50462 4 Nati
2、onal foreword This British Standard was published by BSI. It is the UK implementation of ISO 9683-1:2006. It supersedes BS 7020-11-1:1993 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ISE/58, Iron ores. A list of organizations represented on ISE/58
3、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 since publicati
4、on Amd. No. Date Comments Reference number ISO 9683-1:2006(E)INTERNATIONAL STANDARD ISO 9683-1 First edition 2006-12-01 Iron ores Determination of vanadium Part 1: BPHA spectrophotometric method Minerais de fer Dosage du vanadium Partie 1: Mthode spectrophotomtrique la BPHA BS ISO 9683-1:2006ii iii
5、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 . 4 7 Procedure 4 7.1 Number of determinations . 4 7.2 Test portion . 4 7.3 Blank test and check test. 4
6、 7.4 Determination 4 7.4.1 Decomposition of the test portion 4 7.4.2 Colour development and extraction . 5 7.4.3 Spectrophotometric measurement . 5 7.4.4 Calibration. 5 8 Expression of results. 6 8.1 Calculation of mass fraction of vanadium . 6 8.2 General treatment of results 6 8.2.1 Repeatability
7、and permissible tolerance 6 8.2.2 Determination of analytical result. 7 8.2.3 Between-laboratories precision 7 8.2.4 Check for trueness . 8 8.2.5 Calculation of final result. 8 8.3 Oxide factor. 9 9 Test report. 9 Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values
8、 for test samples 10 Annex B (informative) Derivation of repeatability and permissible equations 11 Annex C (informative) Precision data obtained by international analytical trials . 12 BS ISO 9683-1:2006iv Foreword ISO (the International Organization for Standardization) is a worldwide federation o
9、f 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. In
10、ternational organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with
11、the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval
12、 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 subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 9683-1 was prepared by Technical Committee
13、 ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis. This first edition of ISO 9683-1 cancels and replaces ISO 9683:1991, which has been technically revised. It has been updated to alter the manner in which precision data are presented. ISO 9683 consists of the follow
14、ing part, under the general title Iron ores Determination of vanadium: Part 1: BPHA spectrophotometric method The following part is under preparation: Part 2: Flame atomic absorption spectrometric method BS ISO 9683-1:2006 1 Iron ores Determination of vanadium Part 1: BPHA spectrophotometric method
15、WARNING This part of ISO 9683 may involve hazardous materials, operations and equipment. This part of ISO 9683 does not purport to 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 app
16、licability of regulatory limitations prior to use. 1 Scope This part of ISO 9683 specifies a spectrophotometric method using N-benzoyl-phenylhydroxylamine (BPHA) for the determination of the mass fraction of vanadium in iron ores. This method is applicable to mass fractions of vanadium between 0,005
17、 and 0,5 % in natural iron ores, iron ore concentrates and agglomerates, including sinter products. 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 late
18、st edition of the referenced document (including any amendments) applies. ISO 648, Laboratory glassware 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 Specificati
19、on and test methods ISO 7764, Iron ores Preparation of predried test samples for chemical analysis 3 Principle A test portion is decomposed by fusion with sodium peroxide, and leached with water and sulfuric acid. Orthophosphoric acid is added to an aliquot and the vanadium is oxidized to the pentav
20、alent state by potassium permanganate. The excess permanganate is reduced by sodium nitrite in the presence of urea. A complex is formed by treatment with BPHA and hydrochloric acid, and the complex is extracted with chloroform. The absorbance is measured spectrophotometrically at approximately 535
21、nm. BS ISO 9683-1:20062 4 Reagents During the analysis, use only reagents of recognized analytical grade and only water that complies with grade 2 of ISO 3696. 4.1 Iron metal powder, of mass fraction of vanadium 0,001 %. 4.2 Sodium peroxide, fine powder. 4.3 Hydrochloric acid, 1,16 g/ml to 1,19 g/ml
22、, diluted 4 + 1. 4.4 Sulfuric acid, 1,84 g/ml, diluted 1 + 4. 4.5 Orthophosphoric acid, 1,7 g/ml, diluted 1 + 1. 4.6 Hydrogen peroxide, 300 g/l solution. 4.7 Sodium nitrite, 3 g/l solution. 4.8 Urea, 250 g/l solution. 4.9 Potassium permanganate, 3,2 g/l solution. Dissolve 3,2 g of potassium permanga
23、nate in 100 ml of water. Boil gently for about 1 h, filter through a carefully cleaned fine-texture glass filter funnel into a 1 000 ml one-mark volumetric flask, dilute to volume with water and mix. Store the solution in a brown bottle. 4.10 Sodium tripolyphosphate, 100 g/l solution. Dissolve 25 g
24、of sodium tripolyphosphate in 170 ml of water, dilute to 250 ml and mix. 4.11 Background solution. Place 1,300 g of pure iron (4.1) in a zirconium or vitreous carbon crucible (5.1) containing 4,0 g of sodium peroxide (4.2). Add another 4,0 g of sodium peroxide, mix thoroughly with a glass rod or nic
25、kel spatula and tamp the mixture. Place the crucible for 1 min or 2 min at the entrance of a muffle furnace (5.2), the temperature of which is regulated at 420 C 10 C, and then transfer it to the closed furnace for at least 1 h to effect sintering. Remove the crucible from the furnace and cool to ro
26、om temperature. Place the crucible containing the sintered mass in a dry 400 ml beaker, cover with a watch-glass and, momentarily lifting the cover, add 5 ml of water around the sinter cake. When the reaction has subsided, add a further 15 ml of water in the same way. After several minutes, when the
27、 reaction has subsided again, empty the crucible into the 400 ml beaker, rinsing with approximately 10 ml of water. Cautiously pour 30 ml of sulfuric acid (4.4) into the crucible, heat gently, if necessary, to dissolve any residue, and transfer the solution to the beaker, rinsing with about 10 ml of
28、 water. Cautiously add 100 ml of sulfuric acid (4.4) and mix with a glass rod. Add 1 to 2 drops of hydrogen peroxide (4.6) while stirring, until a clear yellow solution is obtained. Boil for about 2 min, cool, transfer to a 200 ml one- mark volumetric flask, dilute to volume with water and mix. 4.12
29、 Chloroform. 4.13 N-Benzoyl-phenylhydroxylamine (BPHA), 2,5 g/l chloroform solution. 4.14 Vanadium, standard solutions. 4.14.1 Vanadium stock solution, 1 000 g V/ml. BS ISO 9683-1:2006 3 Dry several grams of ammonium metavanadate (NH 4 VO 3 ) in an air oven at 100 C for 1 h and cool to room temperat
30、ure in a desiccator. Weigh, to the nearest 0,000 2 g, 2,296 3 g of the dried product into a 600 ml beaker, add 400 ml of hot water and heat gently to dissolve. Cool, carefully add 50 ml of sulfuric acid (4.4), transfer to a 1 000 ml one-mark volumetric flask, quantitatively, dilute to volume with wa
31、ter and mix. 4.14.2 Vanadium standard solution, 50 g V/ml. Introduce 5,0 ml of vanadium stock solution (4.14.1) to a 100 ml one-mark volumetric flask containing 70 ml of water and 5 ml of sulfuric acid (4.4). Cool, dilute to volume with water and mix. 4.15 Calibration solutions. To each of six 125 m
32、l separating funnels, add 25,0 ml of background solution (4.11) and 7 ml of orthophosphoric acid (4.5). Using pipettes, add the quantities of vanadium standard solution (4.14.2) and water as given in Table 1 to the respective separating funnels, and mix by swirling. Table 1 Calibration solutions Van
33、adium standard solution (4.14.2) Water Vanadium concentration in the measured solution ml ml g/ml 0 0,5 1,0 2,0 3,5 5,0 5,0 4,5 4,0 3,0 1,5 0 0 0,5 1,0 2,0 3,5 5,0 For colour development and extraction, proceed as directed in 7.4.2, beginning at “Add 0,8 ml of potassium permanganate solution (4.9) .
34、“ 5 Apparatus Ordinary laboratory apparatus, including one-mark pipettes and one-mark volumetric flasks complying with the specifications of ISO 648 and ISO 1042, respectively, and the following. 5.1 Zirconium metal or vitreous carbon crucible, of capacity approximately 50 ml. 5.2 Muffle furnace, ca
35、pable of being regulated at 420 C 10 C. 5.3 Spectrophotometer. 6 Sampling and samples 6.1 Laboratory 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 wa
36、ter 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 7764. BS ISO 9683-1:20064 6.2 Preparation of predried test samples Thoroughly mix the laboratory sample and, taking multiple inc
37、rements, 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 C 2 C, as specified in ISO 7764. (This is the predried test sample.) 7 Procedure 7.1 Number of determinations Carry out the analysis at least in duplicate in a
38、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 shall
39、be carried out either by the same operator at a different time or by a different operator, including, in both cases, appropriate recalibration. 7.2 Test portion Taking several increments, weigh, to the nearest 0,000 2 g, approximately 0,5 g of the predried test sample obtained in accordance with 6.2
40、. 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 parallel with the analysis of the ore sample
41、(s) under the same conditions. In a blank test, 25 ml of the background solution shall be used in place of the aliquot of the test solution. 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 a
42、s the sample to be analysed and the properties of the two materials should be sufficiently similar to ensure that, in both cases, no significant changes in the analytical procedure will become necessary. Where the analysis is carried out on several samples at the same time, the blank value may be re
43、presented 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 material may be used. 7.4 Determinati
44、on 7.4.1 Decomposition of the test portion Place 2,00 g of sodium peroxide (4.2) in a zirconium or vitreous carbon crucible (5.1). Immediately add the test portion (7.2) and mix well using a glass rod or a nickel spatula. Fuse over a burner and swirl the crucible until the melt is cherry red and cle
45、ar. Remove from the heat and swirl cautiously to cause the cooling melt to solidify in a thin layer on the wall of the crucible. Now place the crucible and contents in a dry 300 ml beaker. Cover with a watch-glass and, momentarily lifting the cover, add 5 ml of water to the crucible. When the efferv
46、escence has ceased, empty the crucible into the beaker, rinsing with approximately 5 ml of water. Add 32 ml of sulfuric acid (4.4) to the beaker via the crucible, wash the crucible with 5 ml of water and remove the crucible. BS ISO 9683-1:2006 5 Add 1 to 2 drops of hydrogen peroxide (4.6) until a cl
47、ear yellow solution appears. Boil for about 2 min, cool, transfer to a 50 ml one-mark volumetric flask, dilute to volume with water and mix. (This is the test solution.) 7.4.2 Colour development and extraction Using a pipette, introduce appropriate aliquots (see Table 2) of the test solution and bac
48、kground solution into a 125 ml separating funnel, add 7 ml of orthophosphoric acid (4.5) and 5 ml of water, and mix by swirling. Table 2 Dilution guide for test solution Mass fraction of vanadium Aliquot of the test solution (7.4.1) Aliquot of the background solution (4.11) Mass of vanadium in the a
49、liquot % ml ml g 0,005 to 0,10 0,10 to 0,20 0,20 to 0,50 25 10 5 0 15 20 12,5 to 250 100 to 200 100 to 250 Add 0,8 ml of potassium permanganate solution (4.9), mix by swirling and stand for 4 min. Add 5 ml of urea solution (4.8), and then add 1 ml of sodium nitrite solution (4.7) drop by drop while swirling, and allow to stand for 1 min. Add 25 ml of hydrochloric acid (4.3) and 10 ml of BPHA solution (4.13), and shake for 45 s. Allow the
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