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1、International Standard 4689 0 N 4 a!i! INTERNATLONAL ORGANIZATION FOR STANDARDIZATlON*MEXAYHAPOAHAR OPI-AHHBAl prepare immediately before use. 4.11 Barium chloride (BaClz.2HzO), 166 g/l solution. Dissolve 166 g of crystalline barium chloride dihydrate (BaClz.2HzO) in 1 litre of water, cover and heat
2、 to boiling point. Keep warm on a water bath for a minimum of 2 h and allow to cool to room temperature overnight. Store the solution in a plastics bottle and before each use, filter the required volume through a close-texture filter paper. 4.12 Hydrochloric acid wash solution, containing barium chl
3、oride. Filter 10 ml of barium chloride solution (4.11) through a close- texture filter paper, and dilute to 1 666 ml with hydrochloric acid solution (4.7). 1 -,-,- 4.13 Sodium nitrate (NaNOs), saturated solution. 4.14 Sodium carbonate (Na$Os), 20 g/l solution. Store in a plastics bottle. 4.15 Ammoni
4、um thiocyanate (NH 8.1 Calculation of sulfur content a, is the within-laboratory standard deviation; The sulfur content, ws, is calculated as a percentage by mass, to five decimal places, using the equation w (%) = (ml - + - ( m3 - m411 x 0,137 4 x 160 S m5 = h - m2) - h3 - mqi x 13,74 *a (I) m5 whe
5、re ml is the mass, in grams, of the platinum crucible contain- ing barium sulfate from the test portion; m2 is the tare, in grams, of the platinum crucible used for the determination; mg is the mass, in grams, of the platinum crucible for the blank test; m4 is the tare, in grams, of the platinum cru
6、cible for the blank test; m5 is the mass, in grams, of the test portion (7,3); 0,1374 is the mass ratio of sulfur in barium sulfate. 8.2 General treatment of results M.1 Repeatability and permissible tolerance The precision of this analytical method is expressed by the following regression equations
7、: I) r = 0,026 x -I? 0,004 . I I (2 P = 0,027 X -I- 0,006 I (3) Qr = 0,009 x -I- 0,002 I I (4) QL = 0,607x -I- 0,002 . . (5) where X Is the sulfur content, expressed as a percentage by mass, of the predried test sample, calculated as follows: - within-laboratory equations (2, 4); the arithmetic mean
8、 of the duplicate values, - between-laboratories equations (3, 5): the arith- metic mean of the final results (8,2,3I of the two labora- tories; r is the permissible tolerance within a laboratory (repeatability); a is the between-laboratories standard deviation. 8.2.2 Acceptance of analytical values
9、 The result obtained for the certified reference material shall be such that the difference between this result and the certified value of the certified reference material is statistically insignifi- cant. For a certified reference material that has been analysed by at least 10 laboratories using me
10、thod(s) that are comparable both in accuracy and precision with this method, the following condition may be used to test the significance of the dif- ference: / n J SL WC $c + G I4-42 N “2, + aL2+ ; . . . (6) c where A, is the certified value; A is the result or the mean of results obtained for the
11、cer- tified reference material; sLc is the between-laboratories standard deviation of the certifying laboratories; swc is the within-laboratory standard deviation of the cer- tifying laboratories; nWc is the average number of replicate determinations in the certifying laboratories: N, is the number
12、of certifying laboratories: n is the number of replicate determinations on the reference sample (In most cases, n = 1) ; at, and or are as defined in 8.2.1. If condition (6) is satisfied, i.e. if the left-hand side of the condi- tion is less than or equal to the right-hand side, then the dif- ferenc
13、e IA, c Al is statistically insignificant; otherwise, it is statistically significant. When the difference is significant, the analysis shall be repeated, simultaneously with an analysis of the test sample. If the difference Is again significant, the procedure shall be repeated using a different cer
14、tified reference material of the same type of ore. When the range of the two values for the test sample is outside the limit for r calculated according to equation (2) in 8.2.1, one or more additional tests shall be carried out in accordance with the flowsheet presented In annex A, simultaneously wi
15、th an analysis of a certified reference material of the same type of ore. I) Additlonal lnfsrmatlon Is given in annex 6 and annex C. 4 IS0 4669;1966 (E) Acceptability of the results for the test sample shall in each case be subject to the acceptability of the results for the certified reference mate
16、rial. NOTE - The following procedure should be used when the informa- tion on the reference material certificate is incomplete: a) if there are sufficient data to enable the between-laboratories standard deviation to be estimated, delete the expression $wC/nwC and regard .sL, as the standard deviati
17、on of the laboratory means; b) if the certification has been made by only one laboratory or if the interlaboratory results are missing, use the following condition: 8.2.3 Calculation of final result The final result is the arithmetic mean of the acceptable analytical values for the test sample or as
18、 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) when 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) when t
19、he figure in the fourth decimal place is 5 and there is a figure other than 0 in the fifth decimal place, or when the figure in the fourth decimal place is greater than 5, the figure in the third decimal place is increased by one; cl when the figure in the fourth decimal place is 5 and there is the
20、figure 0 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; 9 Test report The test report shall include the following information: a) reference to this International Sta
21、ndard; b) details necessary for the identification of the sample; cl result of 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, or in the International Standards to which refere
22、nce is made, which may have influenced the result, either for the test sample or the certified reference material(s). -,-,- IS0 4669-1966 (E) Annex A Flowsheet of the procedure for the acceptance of analytical values for test samples (An integral part of this International Standard.) Range of xl, x2
23、, x3, x4, 1,3 r NO X = Median of x1, x2, x3, x4 r : as defined in 8.2.1, 6 IS0 4666-1666 (E) Annex B Derivatiori of repeatability and permissible tolerance equations (This annex is for information only, and is not an integral part of this International Standard.) The regression equations in 8.2.1 ha
24、ve been derived from the results of international analytical trials carried out in 1974/1975 on five iron ore samples involving 23 laboratories in six countries. Graphical treatment of the precision data is given in annex C. The test samples used were: Sample Sulfur content 1% (m/m)1 Nimba 0,006 Kir
25、una D 0,019 Rompin 0,078 Texada 0,255 Roasting residue (Purpurerz) 0,534 NOTES 1 A report of the international trial and a statistical analysis of the results (Document ISO/TC 102/SC 2 N 446 E, April 1976) is available either from the Secretariat of ISO/TC 102/SC 2 or from the Secretariat of ISO/TC
26、102. 2 The statistical analysis has been performed in accordance with the principles embodied In IS0 6725. -,-,- IS0 4666-1.966 (El Annex C Precision data obtained by international analytical trial (This annex is for information only, and is not an integral part of this International Standard.) NOTE - This figure Is a graphical presentation of the equations in 8.2.1. 0,035 0,030 0,025 g 0,020 C .o 08 E 0,015 0,010 0,005 0,000 o,o 0 P 0 r o,l 0,2 0,3 0,4 0,s Sulfur content 1% (m/m)1 0,6 0,7 0,8 0,9 Figure - Least-squares fit of precision against X for sulfur 6 -,-,-