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1、International Standard $ 6830 0 a 4 4fm INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON*MEYHAPOHAR OPrAHM3AlWi ll0 CTAHAPTH3Al16 to I,19 g/ml. 4.5 Hydrochloric acid, Q 1,16 to I,19 g/ml diluted 1 + 5. 4.6 Hydrochloric acid, Q I,16 to 1,19 g/ml diluted 1 + I. 4.7 Ammonia, solution. Ammonia (Q 0,866 to
2、 0,896 g/ml) diluted 1 + 1. 4.8 Ammonium chloride (NH or zirconium crucible of 56 ml capacity. 52 Magnetic stirrer, with a polytetrafluorethylene-coated bar. 6.3 Spatula, of non-magnetic material or demagnetized stainless steel (for example austenitic stainless steel). 6.4 Burette, conforming to the
3、 specifications in IS0 385/l. 6.1 Laboratory sample For analysis, use a laboratory sample of minus 100 pm particle size which has been taken in accordance with IS0 3081 or IS0 3682, and prepared in accordance with IS0 3682 or IS0 3683. In the case of ores with significant contents of com- bined wate
4、r or oxidizable compounds, use a particle size of minus 166 pm. NOTE - A guideline on significant contents of combined water and oxidizable compounds is incorporated in IS0 7764. 6.2 Preparation of predried test samples Thoroughly mix the laboratory sample and, taking multiple in- crements, extract
5、a test sample in such a manner that it is representative of the whole contents of the container. Dry the test sample at 105 +I 2 OC as specified in IS0 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 a
6、nnex A, independently, on one predried test sample. NOTE - The expression “independently” means that the second and any subsequent result is 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
7、 either by the same operator at a different time of by a different operator including, in either case, ap- propriate recalibration. 7.2 Blank test and check test In each run, one blank test and one analysis of a certified reference material of the same type of ore shall be carried out in parallel wi
8、th the analysis 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. NOTE - The certified reference material should be of the same type as the sample to be analysed and the properties of the two materials sh
9、ould 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 test samples at the same time, the blank value may be represented by one test, provided that the procedure is the same and
10、 that the reagents used are from the same reagent bottles. The blank test shall contain all reagents in the same amounts as added to the test portion during analysis. When the analysis is carried out on several test samples of the same type of ore at the same time, the analytical value of one certif
11、ied reference material may be used. 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 00:31:24 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6630-
12、1666 (E) 7.3 Test portion Taking several increments, weigh, to the nearest 0,000 2 g, the amount of predried test sample (6.2) specified in the table in accordance with the expected aluminium content. NOTE - The test portion should be taken and weighed quickly in order to avoid reabsorption of moist
13、ure. 7.4 Determination 7.4.1 Dissolution of the test portion Transfer 0,50 g of sodium carbonate (4.1) into a dry crucible (5.1). Add the test portion (7.3) to the crucible, followed by2 g of sodium peroxide (4.2). Mix the contents with a dry spatula (5.3). Fuse over a Meker burner (low heat) swirli
14、ng the crucible until the melt is cherry red and clear. Remove from the heat and swirl until the melt solidifies on the inner wall of the crucible. Place the crucible in a dry 250 ml beaker. Cool. Cover with a watch-glass and add about 10 ml of water to the crucible. After effervescence ceases, empt
15、y the contents of the crucible into the beaker and wash the crucible with about IO ml of water. Add 20 ml of hydrochloric acid (4.6) via the crucible into the beaker. Rinse the crucible with water and add the rinsings to the beaker. Dilute to about 70 ml with water. 7.4.2 Removal of interfering elem
16、ents Bring the contents of the beaker to the boil. Add ammonia solution (4.7) dropwise until the precipitation of hydroxides is complete (pH 6,5). Bdil for 1 min and immediately filter through a rapid paper. Retain this beaker. Wash the paper and precipitate five times with hot ammonium chloride sol
17、ution (4.8). Then wash five times with hot water. Discard the filtrate. Place the unfolded filter paper, with the precipitated hydrox- ides, on the inner wall of the retained beaker and wash down the precipitate with a fine jet of hot water. Then wash down the filter paper with 25 ml of hot hydrochl
18、oric acid (4.6). Finally wash with a jet of hot water, and discard the filter paper. Cover the beaker with a watch-glass and bring the contents to the boil. Rinse. Cool to below 20 “C and adjust the volume to 50 ml using water. NOTE - Prior to and during the extraction ensure that all reagents in- c
19、luding water are cooled to below 20 OC. Transfer the solution to a 250 ml separating funnel. Use 25 ml of water for rinsing the beaker and add to the separating funnel. Add 20 ml of cupferron solutipn (4.9). Mix slightly, Add 20 ml of chloroform (4.10). Shake vigorously for 1 min. Allow the layers t
20、o separate. Drain off the lower organic layer. Add 5 ml of chloroform (4.10) to the separating funnel fo displace the cupferrates on the surface of the aqueous layer. Drain off the organic layer. Carry out additional treatment with cupferron (4.9) and chloroform (4.10) as shown in table 1 (commensur
21、ate with the mass of test portionl. Finally add two successive 20 ml portions of chloroform (4.10) to the aqueous phase, shaking vigorously for 1 min. Allow to settle and separate. Drain off and reject the organic layer. Wipe the stem of the separating funnel with a filter paper wick. Drain the aque
22、ous phase into a 250 ml beaker, rinsing with 5 ml of hydrochloric acid (4.5). Boil for a few minutes. Remove from the heat. Add 5 ml of nitric acid (4.3) and 10 ml of perchloric acid (4.11). Cover with a ribbed cover glass. Evaporate nearly to dryness. Remove from the heat. Add 10 ml of hydrochloric
23、 acid (4.6). Heat to dissolve the salts and thenadd 50 ml of water and bring to the boil. Filter through a rapid paper washing with hot water several times. Cool the filtrate. 7.4.3 Titration Add, by means of a pipette, an excess of EDTA (4.18) (25 ml is sufficient) to the filtrate. Adjust the pH to
24、 2,5 measured by pH meter, by the dropwise addition of sodium hydroxide (4.121, then adjust the pH to 4 by the dropwise addition of sodium hydroxide (4.13). Dilute the contents to 100 ml with water. Cover the beaker and bring the contents to the boil. Keep boil- ing gently for 10 min. Cool. Add 15 m
25、l of acetate buffer (4.141, and 7 drops (about 0,3 ml) of xylenol orange indicator (4.16). Stir the solution using the magnetic stirrer (5.2). Titrate with zinc standard volumetric solution (4.17). The colour changes to a persistent (30 s) pink at the end-point. Add 10 ml of ammonium fluoride soluti
26、on (4.151, heat the con- tents to boiling and boil gently for 10 min. Cool and add 2 to 3 drops of xylenol orange indicator (4.16). Stir the solution and titrate the liberated EDTA with zinc standard volumetric solu- tion (4.17). The colour changes to a persistent (30 s) pink at the end-point. Recor
27、d the fitre, V ml. Table - Mass of test portion and extraction volume Expected Mass of Second extraction Third extraction aluminium content test portion Cupferron Chloroform Cupferron Chloroform % h/m) 9 ml ml ml ml 0,25 to 1,O 0,3 20 20 15 20 1.0 to 2,5 02 15 20 - - 2.5 to 5,0 0.1 10 20 - - 3 Copyr
28、ight International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 00:31:24 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6830-1986 (El 8 Expression of results 8.2.2 Acce
29、ptance of analytical values The result obtained for the certified reference material (7.2) shall be such that the difference between this result and the certified value of the reference material is statistically insignifi- cant. For a certified reference material that has been analysed by at least 1
30、0 laboratories using method(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: 8.1 Calculation of aluminium content The aluminium content, as a percentage by mass, is calculated to four decimal pla
31、ces using the equation WA,(%) = 0,026 88 x V . . . (1) m where V is the volume, in millilitres, of zinc standard volumetric solution (4.17) used in 7.4.3; m is the mass, in grams, of the test portion (7.3); 0,026 98 is the relative atomic mass of aluminium times 10e3. 8.2 General treatment of result
32、s11 8.2.1 Repeatability and permissible tolerance The precision of this analytical method is expressed by the following regression equations): r = 0,028 9 X + 0,016 7 . . . (2) P = 0,042 2 X + 0,032 3 *.a (3) br = 0,010 4 x + 0,006 0 . . . (4) CL = 0,013 4 x + 0,010 2 em. (5) X is the aluminium cont
33、ent of the predried test sample, expressed as a percentage by mass, calculated as follows: - within-laboratory equations (2, 4); the arithmetic mean of the duplicate values, - between-laboratory equations (3, 5); the arithmetic mean of the final results (8.2.3) of the two laboratories; r is the perm
34、issible tolerance within a laboratory (repeatability); P is the permissible tolerance between laboratories: or is the within-laboratory standard deviation; crL is the between-laboratories standard deviation. . . . (6) A, is the certified value; A is the result or the mean of results obtained for the
35、 cer- tified reference material; sLc is the between-laboratories standard deviation of the certifying laboratories; swc is the within-laboratory standard deviation of the certifying laboratories; nWc is the average number of replicate determinations in the certifying laboratories; N, is the number o
36、f certifying laboratories; n is the number of replicate determinations on the certified reference material (in most cases n = 1); oL and cr, are as defined in 8.2.1. If condition (bl is satisfied, i.e. if the left-hand side of condition (6) is less than or equal to the right-hand side, then the dif-
37、 ference IA,-,4 1 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 differ
38、ent certified 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) of 8.2.1, one or more additional tests shall be carried out in accordance with the flowsheet presented in annex A, simultaneo
39、usly with an analysis of a certified reference material of the same type of ore. Acceptability of the results for the test sample shall in each case be subject to the acceptability of the results for the certified reference material. II Additionnal information is given in annex B and annex C. Copyri
40、ght International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 00:31:24 MDTNo reproduction or networking permitted without license from IHS -,-,- Is0 6630-1666 (El NOTE - The following procedure shou
41、ld 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 $,c/+,c and regard sLc as the standard deviation of the laboratory means; b) if the cert
42、ification has been made by only one laboratory or if the interlaboratory results are missing, use the following condition: i 02 p,412 ,a,+; . . . (7) 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 otherwise de-
43、 termined by the operations specified in annex A, 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 i
44、n the third decimal place is 5 and there is a figure other than 0 in the fourth decimal place, or when the figure in the third decimal place is greater than 5, the fiaure in the second decimal Dlace is increased bv one: c) when the figure in the third decimal place is 5 and there is the figure 0 in
45、the fourth decimal place, the 5 is discarded and the figure in the second decimal place is kept un- changed if it is 0,2,4, 6 or 8, and is increased by one if it is 1, 3, 5, 7.0r 9. 8.3 Oxide factor “Q03 (%) = 1,889 5 x WA1 (%I 9 Test report The test report shall include the following information: a
46、) reference to this International Standard; b) details necessary for the identification of the sample; c) 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 which may ha
47、ve influenced the result, either for the test sample or the certified reference material(s). 5 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 00:31:24 MDTNo reproduction or netw
48、orking permitted without license from IHS -,-,- IS0 6930-1966 (El Annex A Flowsheet of the procedure for the acceptance of analytical values for test samples (An integral part of this International Standard.) NO NO Range of xl, x2, x3, x4, 1,3r YES f= Xl + x2 + x3 + x4 4 NO F = Median of xl, x2, x3,
49、 x4 r : as defined in 8.2.1. 6 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 00:31:24 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6630-1666 (E) Annex- B Derivation of repeatability and permissible tolerance (This annex is for information on