1、BRITISH STANDARD BS ISO 9517:2007 Iron ores Determination of water-soluble chloride Ion-selective electrode method ICS 73.060.10 BS ISO 9517:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2007 BSI 2007 ISBN 978 0 580 50783 0 Nati
2、onal foreword This British Standard was published by BSI. It is the UK implementation of ISO 9517:2007. It supersedes BS 7020-20:1990 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ISE/58, Iron ores. A list of organizations represented on this commit
3、tee 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 publi
4、cation Amd. No. Date Comments Reference number ISO 9517:2007(E)INTERNATIONAL STANDARD ISO 9517 Second edition 2007-02-01 Iron ores Determination of water-soluble chloride Ion-selective electrode method Minerais de fer Dosage des chlorures solubles dans leau Mthode par lectrode slective des ions BS I
5、SO 9517:2007ii iii Contents Page Foreword iv 1 Scope. 1 2 Normative references. 1 3 Principle. 1 4 Reagents 1 5 Apparatus 3 6 Sampling and samples. 4 6.1 Laboratory sample 4 6.2 Preparation of predried test samples . 4 7 Procedure 4 7.1 Number of determinations . 4 7.2 Blank test and check test. 5 7
6、.3 Temperature setting . 5 7.3.1 Magnetic stirrer/hotplate 5 7.3.2 Laboratory hotplate 5 7.4 Preliminary tests. 5 7.4.1 Electrode-system check test . 5 7.4.2 Contamination check test 5 7.5 Test portion . 5 7.6 Determination 6 7.6.1 Leaching of water-soluble chloride 6 7.6.2 Filtration. 6 7.6.3 Treat
7、ment of the test solution . 6 7.6.4 Measurement of electrode potential . 6 7.6.5 Preparation of calibration graph . 6 7.6.6 Measurement of chloride concentration 7 8 Expression of results. 7 8.1 Calculation of mass fraction of water-soluble chloride 7 8.2 General treatment of results 8 8.2.1 Repeata
8、bility 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 result. 9 9 Test report. 10 Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for test sa
9、mples 11 Annex B (informative) Derivation of repeatability and permissible tolerance equations . 12 Annex C (informative) Graphical presentation of precision data obtained by international analytical trials 13 BS ISO 9517:2007iv Foreword ISO (the International Organization for Standardization) is a
10、worldwide federation of 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
11、 on that committee. International 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 draft
12、ed 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 Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Stan
13、dard 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 subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 9517 was prepared by
14、 Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis. This second edition cancels and replaces the first edition (ISO 9517:1989), which has been technically revised. It has been updated to alter the manner in which precision data are presented. BS I
15、SO 9517:2007 1 Iron ores Determination of water-soluble chloride Ion-selective electrode method WARNING This International Standard may involve hazardous materials, operations and equipment. This International Standard does not purport to address all of the safety problems associated with its use. I
16、t is the responsibility of the user of this International Standard to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies an ion-selective electrode method for the determination of the
17、 mass fraction of water-soluble chloride in iron ores. This method is applicable to a mass-fraction range of 0,007 % to 0,1 % of water-soluble chloride in natural iron ores, concentrates and agglomerates, including sinter products. NOTE Water-soluble chloride is the part of the mass fraction of chlo
18、ride in an iron ore that is extractable by leaching with aqueous solution under substantially neutral conditions. 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 refere
19、nces, the latest 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 7764, Iron ores Preparation of predried
20、 test samples for chemical analysis 3 Principle The test portion is digested in water containing potassium sulfate; the suspension is transferred to a volumetric flask and diluted to volume. The solution is dry filtered, an aliquot is treated with potassium persulfate solution, and neutral buffer is
21、 added. Ionic-strength adjuster solution is added and the chloride concentration is determined potentiometrically using a chloride-ion electrode and a double-junction reference electrode. 4 Reagents During the analysis, use only reagents of recognized analytical grade, and only redistilled water or
22、water of equivalent purity. The preparation of reagent and calibration solutions, and all operations specified in Clauses 5, 6 and 7, shall be conducted in an area adequately isolated from any areas in which hydrochloric acid is used. BS ISO 9517:20072 4.1 Potassium sulfate (K 2 SO 4 ) solution, 2 g
23、/l. 4.2 Potassium sulfate (K 2 SO 4 ) solution, 4 g/l. 4.3 Potassium persulfate (K 2 S 2 O 8 ) solution, 1,5 g/100 ml. Prepare freshly for each series of tests. 4.4 Sodium nitrate solution, c(NaNO 3 ) = 5 mol/l. Dissolve 42,5 g of sodium nitrate in about 60 ml of water, transfer to a 100 ml volumetr
24、ic flask, dilute to volume and mix. 4.5 Phosphate buffer solution. Dissolve 2,72 g of potassium dihydrogen phosphate (KH 2 PO 4 ) and 2,84 g of disodium hydrogen phosphate (Na 2 HPO 4 ) in 40 ml of water. Transfer to a 100 ml volumetric flask, dilute to volume and mix. 4.6 Stirring-bar cleaning solu
25、tion. Add carefully to about 700 ml of water, 150 ml of sulfuric acid ( 1,84 g/ml) and 150 ml of phosphoric acid ( 1,7 g/ml) and mix. 4.7 Chloride standard solution A, 1 000 g of chloride per ml. Dry about 2 g of sodium chloride at 105 C for 1 h and cool in a desiccator. Weigh 0,824 g of the dried m
26、aterial, dissolve in about 50 ml of water and transfer to a 500 ml volumetric flask. Dilute to volume and mix. 1 ml of chloride standard solution A contains 1 000 g of chloride. 4.8 Chloride standard solution B, 50 g of chloride per ml. Measure 25,0 ml of standard chloride solution A into a 500 ml v
27、olumetric flask, dilute to volume and mix. 1 ml of chloride standard solution B contains 50 g of chloride. 4.9 Chloride standard solution C, 20 g of chloride per ml. Measure 10,0 ml of chloride standard solution A into a 500 ml volumetric flask, dilute to volume and mix. 1 ml of chloride standard so
28、lution C contains 20 g of chloride. Standard solutions B (4.8) and C (4.9) should be prepared freshly. 4.10 Calibration solutions. Prepare the calibration solutions specified in Table 1 for the expected range of mass fractions of chloride. If the mass fraction of chloride is unknown, prepare calibra
29、tion solutions containing 5,0 g, 10,0 g and 50,0 g of chloride per ml. If the mass fraction of chloride is then found to be less than 0,012 %, prepare additional calibration solutions containing 2,0 g and 3,0 g of chloride per ml. For higher mass fractions of chlorides, prepare any additional soluti
30、ons required in accordance with Table 1. BS ISO 9517:2007 3 Table 1 Calibration solutions required for each range of mass fraction of chloride Mass fraction of chloride in test sample Concentration in calibration solution % g/ml 0,005 to 0,025 2,0; 3,0; 5,0; 10,0 0,012 to 0,025 5,0; 10,0 0,025 to 0,
31、10 10,0; 25,0; 50,0 For the preparation of the required calibration solutions, measure into a series of 100 ml volumetric flasks the aliquots of chloride standard solutions specified in Table 2. Table 2 Preparation of calibration solutions Chloride concentration in calibration solution Standard-solu
32、tion aliquot volume g/ml ml Standard solution 2,0 10,0 C (4.9) 3,0 15,0 C (4.9) 5,0 10,0 B (4.8) 10,0 20,0 B (4.8) 25,0 50,0 B (4.8) 50,0 5,0 A (4.7) Add to the aliquots of standard solution in the 100 ml volumetric flasks, 6 ml of potassium persulfate solution (4.3), 35 ml of potassium sulfate solu
33、tion (4.2), 2 ml of phosphate buffer solution (4.5) and 2 ml of sodium nitrate solution (4.4) (ionic strength adjuster). Dilute to volume and mix. Calibration solutions containing from 2,0 g to 10,0 g of chloride per ml should be prepared on the day of use. 5 Apparatus Any one-mark pipettes and volu
34、metric flasks required shall comply with the specifications of ISO 648 and ISO 1042, respectively. Ordinary laboratory equipment and the following. 5.1 Magnetic stirrer (optional, see fourth paragraph of 7.6.4). 5.2 Magnetic stirrer/hotplate. 5.3 PTFE or polyethylene-covered stirring bars, 25 mm to
35、30 mm long. Before use, stirring bars shall be cleaned to remove adhering iron ore and chloride contamination by leaching in the cleaning solution (4.6) for 30 min, and then in water for 30 min. Only clean tweezers should be used for handling the cleaned stirring bars. BS ISO 9517:20074 5.4 Filtrati
36、on apparatus, glass or polycarbonate plastic, with 25 mm to 50 mm diameter cellulose membrane microfilters of less than 1 m pore size 1) . The microfilters should at all times be handled only with clean tweezers. 5.5 Ion-selective electrode meter, or high-sensitivity pH meter, or high-impedance mill
37、ivoltmeter, capable of reading with a sensitivity of 0,1 mV. 5.6 Chloride ion-selective electrode and separate double-junction, free-flowing, reference electrode. Both of the electrodes shall be maintained and used in accordance with the manufacturers specifications, and the outer chamber solution i
38、n the reference electrode should be changed as specified and replenished as necessary. The flow rate across the nitrate/test solution junction should be such that the level of the outer chamber solution falls at a rate of approximately 4 mm to 5 mm per day. As some chloride ion-selective electrodes
39、are light sensitive, they should not be used in direct sunlight or in very bright daylight. NOTE “Combined“ electrodes, which normally are not provided with a reference electrode incorporating a double junction, are not suitable. 6 Sampling and samples 6.1 Laboratory sample For analysis, use a labor
40、atory 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 less than 160 m. NOTE A guideline on significant contents of combined water and o
41、xidizable 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 the test sample at 105 C 2 C, a
42、s 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 accordance with Annex A, independently, on one predried test sample. The expression “independently” means that the second and any subsequent result is
43、 not affected by the previous result(s). For this particular analytical method, this condition implies that the repetition of the procedure shall be carried out either by the same operator at a different time or by a different operator including, in either case, appropriate recalibration. 1) Millipo
44、re (XX10 apparatus with HAWP filters), Sartorius, Gelman are examples of suitable apparatus available commercially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of these types of apparatus. BS ISO 9517:2007 5 7.2
45、Blank test and check test NOTE For technical reasons, a blank test, as usually understood, cannot be conducted for methods using ion- selective electrodes. For this method, the procedure in 7.4.2 is substituted. In each run, one analysis of a certified reference material of the same type of ore shal
46、l be carried out in parallel with the analyses 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
47、 of the two materials should be sufficiently similar, to ensure that, in either case, no significant changes in the analytical procedure would become necessary. 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 referen
48、ce material may be used. 7.3 Temperature setting 7.3.1 Magnetic stirrer/hotplate Determine the temperature setting required to maintain a temperature of 90 C to 95 C in a 35 ml volume of water. 7.3.2 Laboratory hotplate Preheat the hotplate and determine the temperature setting required to produce,
49、in a 50 ml volume of water, a temperature of at least 90 C (but without boiling) after heating for 25 min. 7.4 Preliminary tests 7.4.1 Electrode-system check test Before use of the electrodes for each series of tests, carry out the following check test of the electrode function. Add to a 150 ml or 250 ml beaker, 100 ml of water, a stirring bar (5.3) and 2 ml of sodium nitrate solution (4.4). Place the electrodes in the solution, stir for 5 m
