1、INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXLIYHAPOnHAR OPrAHM3ALlMR n0 CTAHLIAPTM3ALWiA-ORGANISATION INTERNATIONALE DE NORMALISATION Aluminium oxide primarily used for the production of aluminium - Determination of sodium content - Flame emission spectrophotometric meth
2、od Ox yde d aluminium principalemen t u tilise pour la production de I aluminium - Dosage du sodium - Methode par spectrophotometrie de flamme en bmission First edition - 1976-09-15 Ii, I_ F ,a it: : ) , )I 9 $ a,l,ay H,$f, (a lh Ref. No. IS0 1617-1976 (E) . 1 Descriptors : aluminium oxide, chemical
3、 analysis, determination of content, sodium, spectrophotometric analysis. ; Price based on 5 Pages Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-FOREWORD IS0 (the Inter
4、national Organization for Standardization) is a worldwide federation of national standards institutes (IS0 Member Bodies). The work of developing International Standards is carried out through IS0 Technical Committees. Every Member Body interested in a subject for which a Technical Committee has bee
5、n set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their
6、 acceptance as International Standards by the IS0 Council. Prior to 1972, the results of the work of the Technical Committees were published as IS0 Recommendations; these documents are now in the process of being transformed into International Standards. As part of this process, Technical Committee
7、ISO/TC 47 has reviewed IS0 Recommendation R 1617 and found it technically suitable for transformation. International Standard IS0 1617 therefore Replaces IS0 Recommendation R 1617-1970 to which it is technically identical. IS0 Recommendation R 1617 was approved by the Member Bodies of the following
8、countries : Australia Austria Belgium Brazil Chile Czechoslovakia Egypt, Arab Rep. France Germany Greece Hungary of India Iran Israel Italy Korea, Rep. of Netherlands New Zealand Norway Peru Poland Portugal Romania South Africa, Rep. of Spain Sweden Switzerland Thailand Turkey United Kingdom U.S.S.R
9、. Yugoslavia No Member Body expressed disapproval of the Recommendation. No Member Body disapproved the transformation of ISO/R 1617 into an International Standard. o International Organization for Standardization, 1976 l Printed in Switzerland Copyright International Organization for Standardizatio
10、n Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD IS0 1617-1976 (E) Aluminium oxide primarily used for the production of aluminium - Determination of sodium content - Flame emission spectrophotometric met
11、hod 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies a flame emission spectrophotometric method for the determination of the sodium content of aluminium oxide primarily used for the production of aluminium. The method is applicable to products having a sodium content, expressed
12、 as NapO, equal to or greater than 0.05 % (m/m). 2 REFERENCES IS0 802, Aluminium oxide primarily used for the production of aluminium - Preparation and storage of test samples. IS0 2927, Aluminium oxide primarily used for the production of aluminium - Sampling. 3 PRINCIPLE Fusion, at a controlled te
13、mperature, of a test portion of aluminium oxide with a mixture of lithium carbonate and boron trioxide or, as alternative, a mixture of lithium carbonate and lithium tetraborate. Dissolution of the fused mass in hydrochloric acid. Aspiration of the solution into a flame and determination of the sodi
14、um content by measurement of the intensity of the light emitted at a wavelength of 589 nm. 4 REAGENTS During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Lithium carbonate, anhydrous (Li,COa). 4.2 Boron trioxide (B,Oa), or
15、 4.2.1 Boric acid (HaBOa), or 4.2.2 Lithium tetraborate ( Li2B407). NOTE - If crystallized lithium tetraborate pentahydrate (Li26407.5H20) is available, first dehydrate it by gradual heating in a platinum dish. 4.3 Aluminium, 99.99 % pure, in the form of shavings. 4.4 Mercury, extra pure. 4.5 Aceton
16、e, p approximately 0,788 g/ml. 4.6 Hydrochloric acid, p approximately I,19 g/ml, about 38 % (m/m) solution. 4.7 Nitric acid, p approximately I,40 g/ml, about 68 % (m/m) solution. 4.8 Sodium, standard solution corresponding to 2,00 g of Na,O per litre. Weigh, to the nearest 0,001 g, 3,774 g of sodium
17、 chloride, which has been previously dried for about 12 h at 110 “C and cooled in a desiccator, and dissolve in water. Transfer the solution quantitatively to a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. Transfer the solution to a plastics bottle. 1 ml of this standard solution
18、contains 2.00 mg of Na,O. 4.9 Sodium, standard solution corresponding to 0,200 g of Na20 per litre. Take 50,O ml of the standard sodium solution (4.8) place in a 500 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard solution contains 0,200 mg of Na,O. Prepare this solut
19、ion just before use and transfer it to a plastics bottle. 4.10 Sodium, standard solution corresponding to 0,080 g of NaaO per litre. Take 40,O ml of the standard sodium solution (4.8), place in a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard solution contains
20、0,080 mg of Na,O. Prepare this solution just before use and transfer it to a plastics bottle. 1 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 1617-1976 (E) 5 APPARA
21、TUS Ordinary laboratory apparatus and 5.1 Platinum crucible, of upper diameter approximately 50 mm, lower diameter approximately 35 mm and height approximately 40 mm, fitted with a platinum lid, or 5.1 .I Platinum-gold alloy crucible (Au 5 %), having the same dimensions, or 5.1.2 Graphite crucible,
22、of suitable quality and having about the same dimensions as the platinum crucible (5.1). NOTE - Using a sample of Al203 of known Na20 content, a test should be carried out in order to check that the purity and density of the graphite are such as to cause no variation of the NaaO content. A density o
23、f graphite complying with such requirements is equal to or greater than 1.7. 5.2 Open electric furnace, capable of being controlled at 500 + 20 “C. 5.3 Electric furnace, capable of being controlled at 1 100 f 50 “c. 5.4 Borosilicate glass beaker, of capacity approximately 400 ml. 5.5 Borosilicate gl
24、ass beaker, of capacity approximately 600 ml. 5.6 Flame spectrophotometer, provided with an atomizer burner suitably fed to excite the emission of the 589 nm sodium line. 6 PROCEDURE 6.1 Test portion Weigh, to the nearest 0,001 g, 1 g of the test sample, dried at 300 “C (see 3.3 of IS0 802). 6.2 Pre
25、paration of the calibration graph 6.2.1 Preparation of the base solutions 6.2.1.1 PREPARATION OF AN ALUMINIUM CHLOR IDE SOLUTION CORRESPONDING TO log OF A1203 PER LITRE Clean about 6 g of the aluminium (4.3) by dipping into a little of the nitric acid solution (4.7). Wash in water and dry with the a
26、cetone (4.5). Weigh, to the nearest 0,001 g, 5,294 g of the clean dry metal; place in the beaker (5.5) and add approximately 100 ml of water and 95 ml of the hydrochloric acid solution (4.6). introduce 1 drop of the mercury (4.4) to facilitate the dissolution. When the reaction subsides, place the b
27、eaker on a sand bath and maintain a gentle heat until all the aluminium has dissolved. Allow to cool and transfer the solution to a 1 000 ml one- mark volumetric flask. Wash the beaker and collect the washings in the same flask, dilute to the mark and mix. Transfer the solution to a plastics bottle.
28、 6.2.1.2 PREPARATION OF A HYDROCHLORIC ACID SOLUTION OF THE FLUX Place in the beaker (5.4) - 14 g of the lithium carbonate (4.1) and 17,5 g of the boron trioxide (4.2) or 31 g of the boric acid (4.2.1) or - 7.5 g of the lithium carbonate (4.1) and 21 g of the lithium tetraborate (4.2.2). Add approxi
29、mately 50 ml of water and, in small portions, 30 ml of the hydrochloric acid solution (4.6). After the liberation of gas has ceased, place the beaker on a sand bath and stir from time to time with a glass rod until the boric acid is completely dissolved. Dilute to approximately 200 ml with hot water
30、, allow to cool and then transfer to a 250 ml one-mark volumetric flask. Wash the beaker and collect the washings in the same flask, dilute to the mark and mix. Transfer the solution to a plastics bottle. 6.2.2 Preparation of the standard matching solutions (see 8.1) Into a series of eight 100 ml on
31、e-mark volumetric flasks, place, in order, 40 ml of the aluminium solution (6.2.1), 10 ml of the flux solution (6.2.1.2) and then the volumes of standard sodium solution (4.9) shown in the following table : Standard sodium Corresponding mass Mass of Na20 referred solution (4.9) of Nap0 to 100 g of A
32、1203 ml w g 0” 0 0 5.0 1 ,oo 0.25 10.0 2.00 0.50 12.5 2,50 0.625 15.0 3.00 0.75 17,5 3.50 0.875 20.0 4.00 1 ,oo 25.0 5.00 1.25 * Blank test on reagents for the calibration graph, Then dilute to the mark and transfer the solutions to plastics bottles. Use only freshly prepared standard matching solut
33、ions. 6.2.3 Spectrophotometric measurements Switch on the spectrophotometer (5.6) a sufficient time in advance to ensure stabilization. Adjust the sensitivity of the apparatus and the slit aperture in accordance with the characteristics of the apparatus used, ensuring a band width of 6 nm at the mos
34、t, centred on the emission maximum (theoretical value 589 nm). 2 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 1617-1976 (E) Aspirate the series of standard matchin
35、g solutions (6.2.2) into the flame and measure the intensity of the emission. Ensure that the rate of aspiration of the solutions into the flame is kept constant during the preparation of the calibration graph. 6.2.4 Plotting the calibration graph Plot a graph having, for example, the masses, in mil
36、ligrams, of Na,O contained in 100 ml of the standard matching solutions as abscissae and the corresponding values of intensity of emission decreased by the measured value on the blank on the reagents for the calibration graph, on a logarithmic scale, for example, as ordinates. 6.3 Determination 6.3.
37、1 Preparation of test solution Weigh into the crucible (5.1, 5.1 .I or 5.1.2) - 1.40 g of the lithium carbonate (4.1) and - 1.75 g of the boron trioxide (4.2) or 3,lO g of the boric acid (4.2.1) ; or - 0,75 g of the lithium carbonate (4.1) and - 2,lO g of the lithium tetraborate (4.2.2). Mix careful
38、ly, add the test portion (6.1) and mix the whole quantity carefully, preferably with a platinum spatula. Cover the crucible with its lid and place in the open electric furnace (5.2). controlled at 500 + 20 “C, and maintain this temperature until melting of the flux occurs. Transfer the covered cruci
39、ble to the electric furnace (5.3), controlled at 1 100 + 50 “c, without allowing the temperature to exceed 1 150 “C, and maintain this temperature until fusion of the aluminium oxide is complete (approximately 90 min). NOTE - Preliminary grinding of the test portion facilitates melting at a lower te
40、mperature. If grinding is carried out, use a corundum mortar (see 3.3 of IS0 802). Remove the crucible from the furnace and allow to cool in air. Heat it again over the flame of a Bunsen burner and then quickly immerse the base of the crucible in a bath of cold water so as to crack the vitrified mas
41、s. Detach the pieces of the fused mass with the aid of a platinum rod, if necessary tapping the walls of the crucible lightly with a spatula, and collect them in the beaker (5.4). Add 7.5 ml of the hydrochloric acid solution (4.6) into the beaker, and 5 ml into the crucible. Heat the crucible gently
42、 on a sand bath until the residue is completely dissolved. Transfer the solution to the beaker; rinse the crucible several times with hot water, collecting the washings in the beaker. Cover the beaker with a watch-glass and place it on the sand bath. Simmer gently until the fused mass is completely
43、dissolved. Then remove the beaker from the sand bath and allow to cool. Transfer the solution to a 250 ml one-mark volumetric flask, carefully wash the beaker, collecting the washing water in the same flask, dilute to the mark and mix. Transfer the solution to a plastics bottle. 6.3.2 Spectrophotome
44、tric measurements 6.3.2.1 PRELIMINARV MEASUREMENT Carry out a preliminary measurement as specified in 6.2.3 at the same time as the spectrophotometric measurements on the standard matching solutions (6.2.2). 6.3.2.2 BRACKETING MEASUREMENT Carry out a second measurement on the test solution by bracke
45、ting it between two standard matching solutions which differ by only 0,05 g of Na,O (referred to 100 g of AI,O,). Prepare these standard matching solutions using the volumes of the two base solutions (6.2.1 .I and 6.2.1.2) specified in 6.2.2 with the addition of the appropriate volumes of the standa
46、rd sodium solution (4.10). These quantities shall not differ by more than 2,5 ml. 6.4 Blank test 6.4.1 Preparation of the solution In the beaker (5.4), place the same quantities of the flux as used for the preparation of the test solution (see 6.3.1). Add approximately 50 ml of water and 3 ml of the
47、 hydro- chloric acid solution (4.6). Place the beaker on a hot-plate and stir from time to time until dissolution is complete. Continue the heating and stirring in order to eliminate carbon dioxide. Cool and transfer the solution to a 250 ml one-mark volumetric flask, which already contains 100 ml o
48、f the aluminium solution (6.2.1.1). Wash out the beaker carefully, collect the washings in the same flask, dilute to the mark and mix. Transfer the solution to a plastics bottle. 6.4.2 Spectrophotometric measurements Carry out the measurements as specified in 6.2.3 in conjunction with the measuremen
49、ts of the test solution and the standard matching solution specified in 6.3.2.1 and 6.3.2.2. 7 EXPRESSION OF RESULTS The concentration C, expressed in grams per litre, of the solution actually submitted to the spectrophotometer, is given by the formula c= E-E, +(C,-C,)- IC ED-E, f, -El - c,+tc,-C,)- E, -Es 1 where C, is the concentration, in grams per litre, of the weaker standard matching solution used in the deter- mination; 3 Copyright International Organization for Standardization Provided b
