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1、INTERNATIONAL STANDARD IS0 13311 First edition 1997-08-01 Iron ores - Determination of lead content - Flame atomic absorption spectrometric method Minerais de fer - Dosage du plomb - M a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii -,-,- INTERNATIONAL STANDARD Q IS0 IS0 13311:1997(E)
2、Iron ores - Determination of lead content - Flame atomic absorption spectrometric method WARNING - This International Standard may involve hazardous materials, operations and equipment. This International Standard does not purport to address all of the safety issues associated with its use. It is th
3、e 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 spectrometric method for the determination of the lead content of iron ore
4、s. This method is applicable to lead contents between 0,001 % (m/m) and 0,5 % (m/m) in natural iron ores, iron ore concentrates and agglomerates, including sinter products. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions
5、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 possibility of applying the most recent editions of the standards ind
6、icated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 648:1977, Laboratory glassware - One-mark pipettes. IS0 1042:1983, Laboratory glassware - One-mark volumetric flasks. IS0 3081 :1986, iron ores - Increment sampling - Manual method. IS0 3082:1987,
7、 iron ores - Increment sampling and sample preparation - Mechanical method. IS0 3083:1986, iron ores - Preparation of samples - Manual method. IS0 3696:1987, Wafer for analytical laboratory use - Specification and test methods. IS0 7764:1985, Iron ores - Preparation of predried test samples for chem
8、ical analysis. 3 Principle Decomposition of the test portion and removal of silica by treatment with hydrochloric acid and hydrofluoric acid. Oxidation with nitric acid. IS0 13311:1997(E) Q IS0 Evaporation to dryness, followed by dilution and filtration. Ignition of the residue. Fusion with sodium c
9、arbonate. 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 of 4-methyl- 2-pentanone with nitric acid. Evaporation to dryness and dissolution of salts with the re
10、served 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
11、 of recognized analytical grade and only water that complies with grade 2 of IS0 3696. 4.1 Sodium carbonate (NasCOs), anhydrous. 4.2 4-methylQ-pentanone (MIBK), high purity. 4.3 Hydrochloric acid, p 1,16 g/ml to 1 ,19 g/ml. 4.4 Hydrochloric acid, p 1,16 g/ml to 1,19 g/ml, diluted 10 + 6. 4.5 Hydroch
12、loric acid, p 1,16 g/ml to 1,19 g/ml, diluted 1 + 1. 4.6 Hydrochloric acid, p 1,16 g/ml to 1,19 g/ml, diluted 2 + 98. 4.7 Nitric acid, p 1,4 g/ml. 4.8 Hydrofluoric acid, p 1,13 g/ml, 40 % (m/m), or p 1,19 g/ml, 48 % (m/m). 4.9 Lead standard solutions 4.9.1 Lead stock standard solution Dissolve 1,000
13、 g of lead metal of purity 99,5 % (m/m) in 40 ml of nitric acid (p 1,4 g/ml, diluted 1 + 1). Cool and dilute to 1 000 ml in a one-mark volumetric flask and mix. 1 ml of the stock solution contains 1 000 pg of lead. 4.9.2 Standard solution A Transfer 10,O ml of lead stock standard solution (4.9.1) to
14、 a 100 ml volumetric flask. Dilute to volume and mix. 1 ml of this standard solution contains 100 pg of lead. 4.9.3 Standard solution B Transfer 10,O ml of standard solution A (4.9.2) to a 100 ml volumetric flask. Dilute to volume and mix. 1 ml of this standard solution contains 100 pg of lead. 2 -,
15、-,- Q IS0 IS0 13311:1997(E) 5 Apparatus Ordinary laboratory apparatus, including one-mark pipettes and one-mark volumetric flasks complying with the specifications of IS0 648 and IS0 1042 respectively, and 5.1 Polytetrafluoroethylene (PTFE) beaker, of capacity 250 ml, with a PTFE cover. 5.2 Atomic a
16、bsorption spectrometer, equipped with an air-acetylene burner. The atomic absorption spectrometer 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
17、whenever the burner is in operation. a) Minimum sensitivity - the absorbance of the most concentrated calibration solution (see 7.4.4) shall be at least 0,25. b) Graph line A, is the reference/certified value for the CRM/RM; C is a value dependent on the type of CRM/RM used. NOTE 1 Certified referen
18、ce materials used for this purpose should be prepared and certified in accordance with IS0 Guide 35:1989, Certification of reference materials - General and statistical principles. For a CRM certified by an interlaboratory test programme 4 l/2 cf+fV(A) 1 where V(A,) is the variance of the certified
19、value A,. For a CRM certified by only one laboratory 4 1 l/2 c=2 of+- n NOTE 2 This type of CRM should be avoided unless it is known to have an unbiased certified value. 8.2.5 Calculation of final result The final result is the arithmetic mean of the acceptable analytical values for the test sample,
20、 or as otherwise determined by the operations specified in annex A, calculated to five decimal places and rounded off to the third decimal place as follows: a) if the figure in the fourth decimal place is less than 5, it is discarded and the figure in the third decimal place is kept unchanged: b) if
21、 the figure in the fourth decimal place is 5 and there is a figure other than 0 in the fifth decimal place, or if the figure in the fourth decimal place is greater than 5, the figure in the third decimal place is increased by one; cl if the figure in the fourth decimal place is 5 and the figure 0 is
22、 in the fifth decimal place, the 5 is discarded and the figure in the third decimal place is kept unchanged if it is 0, 2, 4, 6 or 8 and is increased by one if it is 1, 3, 5, 7 or 9. 8.3 Oxide factor wpb0 % (m/m) = 1,077 2 wpb % (m/m) 8 -,-,- IS0 IS0 13311:1997(E) 9 Test report The test report shall
23、 include the following information: 4 b) d 4 d f) 9) name and address of the testing laboratory; date of issue of the test report; reference to this International Standard; details necessary for the identification of the sample; result of the analysis; reference number of the result; any characteris
24、tics noticed during the determination, and any operations not specified in this International Standard, which may have had an influence on the result, for either the test sample or the certified reference material(s). IS0 13311:1997(E) Q IS0 Annex A (normative) Flowsheet of the procedure for the acc
25、eptance of analytical values for test samples Start with independent duplicate results I One more determination I p p= Xl+X2;X3+X4 i No P = Median (x1, x2, x3, x4) Rd: as defined in 8.2.1. 10 -,-,- IS0 13311:1997(E) Annex B (informative) Derivation of repeatability and permissible tolerance equation
26、s The regression equations in 8.2.1 were derived from the results of international analytical trials carried out in 1981 and 1982 on five iron ore samples, involving 22 laboratories in nine countries. Graphical treatment of the precision data is given in annex C. The test samples used are listed in
27、table B.l. NOTES Table B.l - Lead content of test samples Sample Lead content % (m/m) Sishen iron ore (76-l 6) 0,001 5 Robe River (76-21) 0,001 4 Stollberg (79-l) 0,097 5 Whyalla Ore (79-l 3) 0,006 6 Purpur Ore (80-l) 0,319 5 1 A report of the international trial and a statistical analysis of the re
28、sults (Documents lSO/TC 102&C 2 N 702, September 1982 and N 740 E, May 1983) are available from either the Secretariat of lSO/TC 102&C 2 or the Secretariat of ISORX 102. 2 The statistical analysis was performed in accordance with the principles embodied in IS0 57251986, Precision of tesf methods - D
29、etermination of repeatability and reproducibility for a standard test method by inter-laboratory tests (now withdrawn). 11 -,-,- IS0 13311:1997(E) IS0 Annex C (informative) Precision data obtained by international analytical trials NOTE - Figure C.l is a graphical presentation of the equations in 8.
30、2.1. 8 .$ 0,025 .F E Ii 0.02 0,015 0.01 0,005 0 0 = Rd A=P + = dd x = q I 0 I 0.05 I 0.1 1 0.15 I 0.2 I 0.25 I I 0,3 0,35 Lead content,% (m/m) Figure C.l - Least-squares fit of precision against X for lead 12 IS0 13311:1997(E) IS0 ICS 73.060.10 Descriptors: minerals and ores, metalliferous minerals, iron ores, chemical analysis, determination of content, lead, atomic absorption spectrometric method. Price based on 12 pages -,-,-