1、International Standard f 6609 0 Q 4 4igB INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEYHAPOHAR OPAHM3At V, is the volume, in millilitres, of standard potassium dichromate solution (4.8) used for titration of the analytical sample; Vs is the volume, in millilitres, of standard potassium dichromaf
2、e solution (4.8) used for titration in the blank test; m is the mass, in grams, of the test portion. 8.2 General treatment of results 8.2.1 Precision The precision of this method, as determined in an International test programme, is expressed in terms of repeatability, reproducibility and reproducib
3、ility index in the fable. Table - Precision data for iron determination Sample Components of Reprodu- standard deviation cibility index % hllml r 1 R 2s MT/1213 5,63 O,N O,C 0,20 MT/1211 17,41 0,14 0,14 0,39 MT/1215 19,50 609 0.12 0,30 MT/ 1212 43.30 0,13 0,12 0,35 where r is the repeatability; R is
4、 the reproducibility. 8.2.2 Acceptance of analytical values (see IS0 57251 The analytical value for the test sample shall be accepted when the analytical value obtained for the corresponding certified reference material agrees with the certified value within the limit of the reproducibility index co
5、ntained in the table, and when the difference between the two values for the test sample does not exceed 2,77 r, as calculated from the appropriate value of r given in the table. When the analytical value obtained for the certified reference material is outside the reproducibility index, an analysis
6、 shall be carried out simultaneously on one test sample and one certified reference material, with one blank test. The analytical value ob- tained 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 certi
7、fied reference material is again ouf- side the limits, the procedure 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 acceptab
8、le analytical values calculated to four decimal places 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
9、5 and there are figures other than 0 in the fourth 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; cl when the figure in the third decimal place is 5 and there are no figures other than 0 in the fourth decima
10、l place, the 5 is discarded and the figure in the second decimal place is kept unchanged if if is 0,2,4,6 or 8, and increased by one if itis1,3,5,7or9. 9 Test report The test report shall include the following information : a) details necessary for the identification of the sample; bl reference to t
11、his International Standard cl results of the analysis; d) reference number of the results; 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. 3 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
