1、INTERNATIONAL STANDARD INTERNATIONAL ORGAN!LATION FOR STANDARDIZATION .ML,k;1SH4PU.H4R OPrAHU34”UR rl0 CTAHLIAPTU34UUU .ORGANISATION INTERNATIONALE DE NORMALISATION Aluminium oxide primarily used for the production of aluminium - Determination of manganese content - Flame atomic absorption method Ox
2、yde daluminium principalement utilise pour la production de Ialuminium - Dosage du mangantke - Methode par absorption atomique dans la flamme First edition - 1976-09-01 ?!“H” $ ij ,j.;1”;3: ;j: ,f ,6” i j-(,:jy;Z.J(;R.i :,;jqj(: + .I* ,!I *i Y r _I ; s . UDC 661.862.22 : 546.711 : 543.422 Ref. No. I
3、S0 3390-1976 (E) Descriptors : aluminium oxide, chemical analysis, determination of content, manganese, spectrophotometric analysis, atomic absorption spectroscopic analysis. Price based on 6 pages Copyright International Organization for Standardization Provided by IHS under license with ISONot for
4、 ResaleNo reproduction or networking permitted without license from IHS-,-,-FOREWORD IS0 (the International 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 Tech
5、nical Committees. Every Member Body interested in a subject for which a Technical Committee has been 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 Standard
6、s adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the IS0 Council. International Standard IS0 3390 was drawn up by Technical Committee ISO/TC 47, Chemistry, and was circulated to the Member Bodies in May 1974.
7、 It has been approved by the Member Bodies of the following countries : Austria Belgium Bulgaria Chile Czechoslovakia Egypt, Arab Rep. of France Germany Hungary India Israel Italy Netherlands New Zealand Poland Portugal No Member Body expressed disapproval of the document. South Africa, Rep. of Spai
8、n Sweden Switzerland Thailand Turkey United Kingdom Yugoslavia 0 International Or9mization for Standardization, 1976 l Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without l
9、icense from IHS-,-,-INTERNATIONAL STANDARD IS0 3390-1976 (E) Aluminium oxide primarily used for the production of aluminium - Determination of manganese content - Flame atomic absorption method 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies a flame atomic absorp- tion method
10、for the determination of the manganese con- tent of aluminium oxide primarily used for the production of aluminium. The method is applicable to products of which the manga- nese content, expressed as Mn, is between 0,000 2 and 0,005 % (m/m) (0,000 258 and 0,006 46 % (m/m), express- ed as MnO). NOTE
11、- If the apparatus available does not have a sufficient sensi- tivity for the lower contents of manganese, it is recommended that there should be pnor extraction of the manganese, by the method specified in annex A. 2 REFERENCES IS0 802, Aluminium oxide primarily used for the produc- tion of alumini
12、um - Preparation and storage of test samples. IS0 2073, Aluminium oxide primarily used for the produc- tion of aluminium - Preparation of sample solution for analysis - Method by means of attack by hydrochloric acid under pressure. 3 PRINCIPLE Dissolution of a test portion by heating in a sealed bor
13、osi- licate tube with hydrochloric acid at a controlled tempera- ture of 250 “C. Aspiration of the solution in an air-acetylene flame and determination of manganese by spectrophotometric measurement of the absorption of the 279,5 nm line emitted by a manganese hollow cathode lamp. 4 REAGENTS During
14、the analysis, use only reagents of recognized analytical grade and only water with a conductivity less than or equal to 50 PSlm. 4.1 Hydrochloric acid, p approximately I,19 g/ml, about 12 N solution. 4.2 Aluminium, acid solution (base solution). Pickle 60 g of extra pure aluminium (assay 99,999 %),
15、in the form of shavings obtained by turning or drilling, in a little nitric acid, p approximately I,40 g/ml. Wash the cleaned shavings with water and then dry them by washing with acetone. Weigh, to the nearest 0.02 g, 53.0 g of the dried shavings, place in a beaker of convenient capacity and add 60
16、0 ml of the hydrochloric acid solution (4.1) and 300 ml of water. introduce 1 drop of mercury to facilitate the attack. Wait until the reaction subsides and then place the beaker on a sand bath or hot-plate and heat gently until all the alumin- ium has been dissolved. Add another 120 ml of the hydro
17、- chloric acid solution (4.1). Allow to cool, transfer quantitatively to a 1 000 ml one mark volumetric flask, dilute to the mark and mix. 4.3 Manganese, standard solution, corresponding to 0,500 g of Mn per litre. 1 ml of this standard solution, prepared according to 4.3.1 or 4.3.2, contains 0,000
18、5 g of Mn. 4.3.1 Weigh, to the nearest 0,000 1 g, 1,802 g of manga- nese(ll) chloride tetrahydrate (MnCl,.4H,O), dissolve in water, transfer quantitatively to a 1 000 ml one-mark volu- metric flask, dilute to the mark and mix. 4.3.2 Weigh, to the nearest 0,000 1 g, 0,500 g of manga- nese, extra pure
19、, place in a beaker of convenient capacity (for example 200 ml) and add 6 ml of water and 6 ml of the hydrochloric acid solution (4.1). Cover the beaker with a clock-glass and warm until the manganese has completely dissolved. Cool to ambient temperature and transfer the solution quantitatively to a
20、 1 000 ml one-mark volumetric flask, dilute to the mark and mix. 4.4 Manganese, standard solution, corresponding to 0,010 g of Mn per litre. Place IO,0 ml of the standard manganese solution (4.3) in a 500 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard solution contai
21、ns 0,010 mg of Mn. 1 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 3390-1976 (El 4.5 Manganese, standard solution, corresponding to 0,001 g of Mn per litre. Place 5
22、0.0 ml of the standard manganese solution (4.4) in a 500 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard solution contains 0,001 mg of Mn. 5 APPARATUS Ordinary laborator apparatus and : 5.1 Apparatus specified in IS0 2073 (clause 5). 5.2 Atomic absorption spectrophoto
23、meter, fitted with a burner fed by air and acetylene (a 100 mm burner is suitable). 5.3 Manganese hollow cathode lamp. 6 PROCEDURE 6.1 Test portion Weigh, to the nearest 0,001 g, 2,00 g of the dried test sample, prepared according to IS0 802 (sub-clause 3.3). clause 3.3). 6.2 Preparation of calibrat
24、ion graph 6.2.1 Preparation of the standard matching solutions Into each of a series of nine 500 ml one-mark volumetric flasks, place 100 ml of the aluminium base solution (4.2) and then respectively the volumes of the standard manga- nese solutions (4.5 or 4.4) indicated in the following table. Dil
25、ute to the mark and mix. Standard manganese solution Corresponding Mn content I No. I ml I mg/l I %I) I 1 02) IO I -I 5.0 0.01 0,000 05 4.5 15.0 0.03 0,000 15 30.0 0.06 0,000 3 50.0 0.10 0,000 5 10.0 0.20 0,001 0 4.4 20.0 0.40 0,002 0 35.0 0.70 0,003 5 50.0 1 ,oo 0.005 0 I) In the test conditions :
26、2 g of test portion in 100 ml of final solution. 2) Blank test on reagents for the calibration graph. 6.2.2 Spectrophotometric measurements Mount the manganese hollow cathode lamp (5.3). Switch on the apparatus (5.2) a sufficient time in advance for it to reach stabilization. Adjust the wavelength t
27、o 279,5 nm and select a slit small enough to separate the 279,5 nm line from the manganese triplet (279.5 - 279,8 - 280,l nm). Adjust the air and acetylene pressures according to the characteristics of the burner so as to obtain an oxidizing flame. Control the rate of aspiration to between 2.5 and 5
28、 ml/min. Aspirate the standard matching solutions (6.2.1) in the flame and measure the intensity of the non-absorbed radiations. Take care to maintain the quantity of solution aspirated in the flame constant with respect to time during all the measurements. Spray water through the burner after- each
29、 measurement. NOTE - Light scattering in atomic absorption spectroscopy is caused by solid particles (mainly refractories) in the flame deflec- ting the light from the hollow cathode lamp, resulting in a high absorbance reading. When using the method without the prior extraction of manganese specifi
30、ed in annex A and if the concentra- tion of aluminium oxide IS 2 g per 100 ml of final solution, there is a considerable degree of light scattering. It is therefore necessary to check the calibration blank solution to determine whether the high absorbance reading IS due to light scattering (in which
31、 case there is no correction to the result) or to traces of manganese present in the aluminium or in the reagents used to prepare the standard matching solutions (in which case a correction must be applied), or to a comblnatlon of the two. Carry out the determination of light scattering as follows :
32、 1) note the absorbance X of the calibration blank solution, measured at the normal wavelength of 279.5 nm; 2) select a non-absorbing wavelength close to the absorbing wavelength (for example 270.2 nm) and adjust rhe gain control until rhe same baseline as for I) IS obtalned. Note the absorbance Y m
33、easured at this wavelength; (X- V) then gives the corrected calibration blank Z; 3) deduct the corrected reading Z from the readings for the standard matching solutions and prepare a calibration graph by plotting absorbance values against the nominal manganese contents of the solutions. 6.2.3 Plotti
34、ng of the calibration graph Plot a graph having, for example, the values, expressed as milligrams per litre, of the quantities of Mn (or MnO) contained in the standard matching solutions as abscissae and the corresponding values of absorbance, decreased by the corrected value Z measured for the blan
35、k on the reagents for the calibration curve, as ordinates. 6.3 Determination 6.3.1 Preparation of the test solution Prepare the test solution by the procedure specified in IS0 2073, using for the attack 14,4 ml of the hydrochloric acid solution (4.1) and 4 ml of water, adjusting the final volume of
36、the solution to 100 ml. 2 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-6.3.2 Blank test Carry out a blank test at the same time as the determina- tion, following the s
37、ame procedure and using the same quantities of all the reagents used for the determination. IS0 3390-1976 (E) where 6.3.3 Spectrophotometric measurements Carry out the measurements on the test solution (6.3.1) and on the blank test solution (6.3.2) at the same time as the spectrophotometric measurem
38、ents on the standard matching solutions (6.2.1), as specified in 6.2.2. 7 EXPRESSION OF RESULTS By means of the calibration graph (6.2.3). determine the masses of Mn corresponding to the absorbance of the test solution and of the blank test solution. The manganese content, expressed as a percentage
39、by mass of Mn, is given by the formula (ml -m2) x 100 m, -m2 1 m,xi0xlOOO m, xl00 m, is the mass, in grams, of the test portion (6.1); ml is the mass, in milligrams, of Mn found in the test solution; m2 is the mass, in milligrams, of Mn found in the blank test solution. The manganese content, expres
40、sed as a percentage by mass of MnO, is given by multiplying the above value by 1,291. 8 TEST REPORT The test report shall include the following particulars : a) the reference of the method used; b) the results and the method of expression used; c) any unusual features noted during the determina- tio
41、n; d) any operation not included in this International Standard or in the International Standards to which reference is made, or regarded as optional. 3 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitte
42、d without license from IHS-,-,-ISO3390-1976 (E) ANNEX A PRIOR EXTRACTION OF MANGANESE A.1 PRINCIPLE After dissolving the test portion, separation of the manganese by extraction of the (2-methyl-8-quinolinol) manganese complex with chloroform from alkaline solution, after addition of tartaric acid an
43、d potassium cyanide, at a pH of 11,8. Evaporation of the chloroform and dissolution of the residue in hydrochloric acid. A.2 REAGENTS Reagents specified in clause 4 and : A.2.1 Chloroform A.2.2 Hydrochloric acid, approximately 0,l N. A.2.3 Tartaric acid, 200 g/l solution. A.2.4 Potassium cyanide, 40
44、 g/l solution. (See clause A.3 “WARNING”). A.25 Sodium hydroxide, 500 g/l solution. A.2.6 2-Methyl-8quinolino1, 20 g/l acetic solution. Dissolve 2 g of 2-methyl-8-quinolinol (C, oHeN0) in about 5 ml of glacial acetic acid, p approximately 1,05 g/ml, and dilute to 100 ml with water. A.3 PREPARATION O
45、F THE TEST SOLUTION WARNING - Because potassium cyanide is extremely poisonous, it must only be handled with all necessary precautions. In particular, do not add acids to solutions containing cyanides, otherwise hydrogen cyanide will be released. Follow the procedure specified in 6.3.1 up to the add
46、ition of the 14,4 ml of the hydrochloric acid solution (4.1) and 4 ml of water. Transfer the solution quantitatively into a beaker of suitable capacity. Cover the beaker and evaporate the solution on a hot-plate just to crystallization. Dissolve the residue in 60 ml of water and add 25 ml of the tar
47、taric acid solution (A.2.3). NOTE - The tartaric acid solution (A.2.3) is added before making the solution alkaline in order to avoid the precipitation of manganese hydroxide and incomplete extraction. A.4 MANGANESE EXTRACTION Slowly add about 18 ml of the sodium hydroxide solution (A.2.5) to the so
48、lution (A.3). with stirring, until the precipitated aluminium hydroxide has completely dissolved. Avoid an excess of sodium hydroxide. Add 10 ml of the potassium cyanide solution (A.2.4), 5 ml of the 2-methyl-8-quinolinol solution (A.2.6) and, with stirring, drop by drop, the sodium hydroxide soluti
49、on (A.2.5) until the quinaldine precipitate has dissolved. Avoid an excess of sodium hydroxide. Cool to ambient temperature and adjust the pH of the solution to 1 I,8 with the sodium hydroxide solution (A.2.5). If the pH is higher, correct it by addition of the hydrochloric acid solution (A.2.2). NOTE - A black precipitate which disappears completely during the extraction is often noticed. Transfer the solution quantitatively to a 200 ml separating funnel and extract
