1、INTERNATIONAL STANDARD IS0 9208 First edition 1989-10-15 Aluminium ores - Determination of vanadium content - BPHA spectrophotometric method Minerais alumineux - Dosage du vanadium - Mkthode spectrophotomktrique au BPHA Reference number IS0 9208 : 1989 (E) Copyright International Organization for St
2、andardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 9208 : 1989 (EI Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The
3、 work of preparing International Standards is normally carried out through IS0 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, govern- mental and non-go
4、vernmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for
5、 approval before their acceptance as International Standards by the IS0 Council. They are approved in accordance witfi IS0 procedures requiring at least 75 % approval by the member bodies voting. International Standard IS0 9208 was prepared by Technical Committee ISO/TC 129, Aluminium ores. Annex A
6、forms an integral part of this International Standard. Annex B is for infor- mation only. 0 IS0 1969 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writi
7、ng from the publisher. International Organization for Standardization Case postale 56 . CH-1211 Geneve 20 . Switzerland Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without
8、license from IHS-,-,-INTERNATIONAL STANDARD IS0 9288 : 1989 (E) Aluminium ores - Determination of vanadium content - BPHA spectrophotometric method 1 Scope This International Standard specifies a BPHA spectrophoto- metric method for the determination of the vanadium content of aluminium ores. It is
9、applicable to ores containing between 0,005 % trnlm) and 0,4 % (m/m) of vanadium pentoxide. 4.1 Sodium peroxide. Use only the dry, free-flowing, off-white to pale yellow granules or powder. WARNING - Sodium peroxide must be protected against humidity and must not be used once it has begun to agglome
10、rate. 2 Normative references 4.2 Iron(lll) oxide, powder 1 1 ml) at a later step in the analysis. If a brown precipitate forms, the fusion and boiling steps should be repeated and the boiling time increased. 2 If the chromium content is known to be more than 0.05 % (m/m), add 1 ml of the sodium sulf
11、ite solution (4.4) (to reduce any yellow colour due to chromium) and add solution drop by drop until any yellow colour is discharged. 3 A small amount of white precipitate may settle out upon standing. This has been found to be innocuous and may be disregarded. 7.5.3 Spectrophotometric determination
12、 Pipette 25,00 ml of the test solution into the prepared separ- ating funnel (5.5). Add potassium permanganate solution (4.6) dropwise until the pink colour persists for at least 5 min. Per- form the following steps upon each solution in turn : a) add 10 ml of BPHA solution (4.7); b) immediately add
13、 20 ml of chilled hydrochloric acid (4.9); c) immediately extract vigorously for 30 s. Allow the phases to separate for at least 10 min. Run the lower phase into a dry 25 ml volumetric flask. Add 10 ml of washed chloroform (4.8) to the separating funnel and extract for a further 30 s. Allow the phas
14、es to separate for at least 10 min, then combine the lower phase with the first extract. Dilute to the mark with washed chloroform and mix. Measure within 24 h, in a spectrophotometer (5.61, the absorbance of the test solution against washed chloroform in cells of optical path length 10 mm (5.7) at
15、530 nm and subtract the value obtained for the blank test solution (7.3). 7.6 Preparation of the calibration graph Pipette 0 ml, 5,OO ml, 10,OO ml, 15,00 ml and 20,OO ml aliquots of the vanadium standard solution (4.11) into 100 ml volumetric flasks. For vanadium contents less than 0,05 % (m/m), use
16、 0 ml, 1,00 ml, 2,00 ml, 5,00 ml and 10.00 ml aliquots. Add 50 ml of matrix solution (4.121, dilute to the mark with water and mix. Take 25.00 ml aliquots of these solutions through the same procedure as the test aliquot specified in 7.5.3. Plot the absorbance of each calibration solution against th
17、e respective mass, in micrograms, of vanadium pentoxide contained in the aliquots. 25 ml aliquots taken from dilutions of 5 ml, 10 ml, 15 ml and 20 ml aliquots of the vanadium standard solution (4.11) correspond respectively to 100 pg, 200 pg, 300 pg and 400 pg of vanadium pentoxide. NOTE - As a gui
18、de to the performance of the method the following information is provided. The calibration solution containing 400 ug of VzOa, when measured at 530 nm using an optical path length of 10 mm and corrected for the zero calibration blank, gave an absorbance of 0,830. 8 Expression of results 8.1 Calculat
19、ion of vanadium pentoxide content The vanadium content, expressed as a percentage by mass of vanadium pentoxide in the test sample is given by the formula m2 250 - x - x 10-4 ml 25 ml is the mass, in grams, of the test portion (7.2); m2 is the mass, in micrograms, of vanadium pentoxide contained in
20、the aliquot of test solution (7.5.31, determined by using the calibration graph (7.6). 3 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 9208 : 1989 (El 8.2 General t
21、reatment of results 8.2.1 Precision A planned trial of this method was carried out by 10 labora- tories at five levels of vanadium, each laboratory making two determinations at each level. The results obtained were treated statistically in accordance with IS0 5725 and the resultant data are presente
22、d in table 1. The data obtained showed a linear relationship between vanadium content, repeatability (rl and reproducibility (RI of the test results as summarized in table 1. Statistical data ob- tained on the NIST standard sample were not used in the regression analysis. The graphical presentation
23、of the precision data is given in annex EL 8.2.2 Acceptance of test results (see annex A) The analytical values for the test sample shall be accepted when the analytical value obtained for the corresponding cer- tified reference material agrees with the certified value within the limit of the value
24、shown for R in table 1 and when the dif- ference between the two values for the test sample does not exceed r, as calculated from the appropriate value of r given in table 1. When the difference exceeds the value of r, one or more additional tests shall be carried out in accordance with annex A, sim
25、ultaneously with a corresponding blank test and an analysis of a certified reference material. When the analytical value obtained for the certified reference material is outside the limits of the value shown for R in table 1, an additional analysis shall be carried out simultaneously on one test sam
26、ple and one certified reference material, with one blank test. The analytical value obtained for the certified reference material shall be examined for the acceptance of the value for the test sample, as above. If the value obtained for the certified reference material is again outside the limits, t
27、he pro- cedure shall be repeated with a different reference material of the same type of ore until two acceptable values for the test sample are obtained. 8.2.3 Calculation of final result The final result is the arithmetical mean of the acceptable analytical values calculated to the fourth decimal
28、place and rounded off to the second decimal place as follows: a) when the figure in the third decimal place is less than 5, it is discarded and the figure in the second decimal place is kept unchanged; b) when the figure in the third decimal place is 5 and there are figures other than 0 in the fourt
29、h decimal place, or when the figure in the third decimal place is greater than 5, the figure in the second decimal place is increased by one; c) when the figure in the third decimal place is 5 and there are no figures other than 0 in the fourth decimal place, the 5 is discarded and the figure in the
30、 second decimal place is kept unchanged if it is 0,2,4,6 or 8, and increased by one if it is 1, 3, 5, 7 org. 9 Test report The test report shall include the following information : a) details necessary for the identification of the sample; b) reference to this International Standard; c) the result o
31、f the analysis; d) reference number of the result; e) any characteristics noticed during the determination and any operations not specified in this International Stan- dard which may have had influence on the results either for the test sample or the certified reference material(s). Table 1 - Precis
32、ion data for vanadium determinations Values in mass percentage Ore type Gibbsite/Boehmite/Hematite 0,024 Diaspore 21,7 % (m/rl of Fe203; 4,0 % (mln) of SiO21 0,053 Gibbsite 0,069 Boehmite/Kaolinite/Gibbsite LO,6 % (m/m) of Crl 0,095 Gibbsite 19,5 % (m/m) of Fe203 0,284 I “1 Certified value: 0,072 %
33、(m/m) k 0,006 % (m/m) Repeatability I Reproducibility r R 0,0031 0,0061 o,OO37 0,006 6 0,0038 0,010 1 0,0037 0.0107 0,013 8 0,020 4 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license fro
34、m IHS-,-,-ISO 9208 : 1989 (El Annex A (normative) Flowsheet of the procedure for the acceptance of test results NO - I Perform x3 jf= x1 + x2 + x3 I x1, x2, x3 6 1,2 r 3 I L - NO Perform x3, x4 Perform x4 Range of x1, x2, x3, x-4 G 1,3 r YES z= x1 + x2 + x3 + x-4 4 X = Median of x1, x2, x3, x4 r : a
35、s defined in 8.2.1. 5 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 9208 : 1989 (E) Annex B (informative) Graphical representation of precision data Coefficients (i
36、I r = A + Bx (ii) R = A + Bx where r = repeatability A = 0,0012 B=0,0061 x = % lmlm) of V205 Regression coefficient = 0,978 1 where R = reproducibility A=0,0045 B = 0,056 3 x = % (m/m) of V,O, Regression coefficient = 0,994 0 0,02 E .- .; 2 a o,o 0,oot 0,006 0,001 0,OO c l- 3- i- / b- z- / I- l t t
37、1 I I I I I I I I I I 0,05 0.1 0,15 0,2 0,25 Ot3 0,35 Vanadium pentoxide content 1% WmIl Figure 1 - Relationship between vanadium pentoxide content and repeatability Ir) and reproducibility (RI UDC 553.492 : 543.42 : 546.881 Descriptors : minerals and ores, aluminium ores, chemical analysis, determination of content, vanadium, spectrophotometric analysis. Price based on 6 pages 6 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
