SIST EN 24938:1997
(Main)Steel and iron - Determination of nickel content - Gravimetric or titrimetric method (ISO 4938:1988)
Steel and iron - Determination of nickel content - Gravimetric or titrimetric method (ISO 4938:1988)
Quality. Rationalization.
Eisen und Stahl - Bestimmung des Nickelgehalts - Gravimetrisches oder titrimetrisches Verfahren (ISO 4938:1988)
Qualitaet. Rationalisierung.
Aciers et fontes - Détermination de la teneur en nickel - Méthode gravimétrique ou titrimétrique (ISO 4938:1988)
Qualité. Rationalisation.
Jeklo in železo - Določevanje niklja - Gravimetrična ali titrimetrična metoda (ISO 4938:1988)
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Eisen und Stahl - Bestimmung des Nickelgehalts - Gravimetrisches oder titrimetrisches Verfahren (ISO 4938:1988)Aciers et fontes - Détermination de la teneur en nickel - Méthode gravimétrique ou titrimétrique (ISO 4938:1988)Steel and iron - Determination of nickel content - Gravimetric or titrimetric method (ISO 4938:1988)77.080.01Železne kovine na splošnoFerrous metals in general77.040.30Kemijska analiza kovinChemical analysis of metalsICS:Ta slovenski standard je istoveten z:EN 24938:1990SIST EN 24938:1997en01-december-1997SIST EN 24938:1997SLOVENSKI
STANDARD
SIST EN 24938:1997
SIST EN 24938:1997
SIST EN 24938:1997
INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXAYHAPOAHAfl OPf-AHM3AL/Mfl n0 CTAH~APTM3AL&lM ISO 4938 First edition 1988-12-01 Steel and iron - Determination of nicke1 content - Gravimetric or titrimetric method Aciers et fontes - Dosage du nicke1 - M6 thode gravimh trique ou titrimb trique Reference number ISO 4938: 1988 (E) SIST EN 24938:1997
ISO 4938 : 1988 (E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 4938 was prepared by Technical Committee ISO/TC 17, S teel. Annexes A and 6 of this International Standard are for information only. 0 International Organkation for Standardkation, 1988 0 Printed in Switzerland SIST EN 24938:1997
INTERNATIONAL STANDARD ISO 4938 : 1988 (El Steel and iron - Determination of nicke1 content - Gravimetric or titrimetric method 1 Scope This International Standard specifies a method for the determination of nicke1 in steel and iron, using either a gravimetric or titrimetric finish. The method is applicable to nicke1 contents from 0,5 % (mlm) to 30 % (mlm). 2 Normative references The following Standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the Standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 377 : 1985, Wrought steel - Selection and preparation of samples and test pieces. ISO 385-1 : 1984, Laboratory glassware - Burettes - Part 7 : General requiremen ts. ISO 648 : 1977, Laboratory glassware - One-mark pipettes. ISO 1042 : 1983, Laboratory glassware - One-mark volumetric flasks. ISO 4793 : 1980, Laboratory sin tered ffrittedl filters - Porosity grading, classifica tion and designa tion. ISO 5725 : 1986, Precision of test methods - Determination of repeatability and reproducibility for a Standard test method by in ter-labora tory tes ts. 3 Principle Dissolution of a test Portion with appropriate acids. Precipitation of the nicke1 as nicke1 dimethylglyoxime. - Cobalt, if present, is oxidized by potassium hexacyanoferrate(II1). - Copper, if present with Cobalt, preferably is removed by controlled-potential electrolysis. Acid dissolution of the precipitate and filtration of the solution, followed by a second precipitation of the nicke1 as nicke1 dimethylglyoxime. In the case of the gravimetric finish, weighing of the dried nicke1 dimethylglyoxime precipitate. In the case of the titrimetric finish, acid dissolution of the precipitate, addition of excess EDTA.Na* Solution and back titration of the excess EDTA.Naz by zinc Solution using xylenol orange as an indicator. 4 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Sodium hydrogen sulfate (Nat-lSO& 4.2 Ethanol, 95 % ( V/ VI. 4.3 Acetic acid, glacial, Q approximately 1,05 g/ml. 4.4 Hydrofluoric acid, Q approximately 1,15 g/ml. 4.5 Nitrit acid, Q approximately 1,40 g/ml. 4.6 Perchlorit acid, Q approximately 1,54 g/ml. 4.7 Sulfuric acid, Q approximately 1,84 g/ml. 4.8 Ammonia Solution, Q approximately 0,90 g/ml. 4.9 Hydrochlorit acid, ,Q approximately IJ9 g/ml, diluted 1 + 1. 4.10 Hydrochlorit acid, Q approximately 1,19 g/ml, diluted 1 + 99. 4.11 Nitrit acid, Q approximately 140 g/ml, diluted 2 + 3. 4.12 Perchlorit acid, Q approximately 154 g/ml, diluted 1 + 49. 1 SIST EN 24938:1997
ISO 4938 : 1988 (El 4.13 Ammonia Solution, Q approximately 0,90 g/ml, diluted 1 + 1. 4.14 Ammonia solution, Q approximately 090 g/ml, diluted 1 + 3. 4.15 Hydrochlorit-nitric acid mixture. Mix 3 volumes of hydrochloric acid, Q approximately 1,19 g/ml, and 1 volume of nitric acid (4.5). Prepare this Solution immediately before use. 4.16 Ammonium acetate, 200 g/l solution. 4.17 Ammonium citrate buffer Solution. Dissolve 500 g of citric acid monohydrate (C6H807.H20) in 675 ml of ammonia Solution (4.8) and dilute to 1 000 ml with water. Filter before use. 4.18 Citric acid, Solution. Dissolve 500 g of citric acid monohydrate (C6H80T.H20) in water and dilute to 1 000 ml with water. Filter before use. 4.19 Dimethylglyoxime, 30 g/l Solution in alkaline medium. Dissolve 20 g of potassium hydroxide in 400 ml of water, add 30 g of dimethylglyoxime (C4H8N202) and stir until dissolution is complete. Dilute to 1 000 ml with water and mix. Filter before use. 4.20 Dimethylglyoxime, 10 g/l Solution in ethanol. Dissolve 10 g of dimethylglyoxime (C4H8N202) in 1 000 ml of ethanol (4.2). Filter before use. 4.21 Hydrazinium(2 + ) sulfate (N2H6S04), 100 g/l Solution. 4.22 Potassium hexacyanoferrate(III), K3 [Fe(CN)el, 100 g/l Solution. This Solution is stable for approximately 30 days. 1 ml corresponds approximately manganese, respectively. to 0,02 g of Cobalt and 4.23 Washing water, adjusted to pH 8 with a few drops of ammonia Solution (4.13). 4.24 Disodium(ethylenedinitrilo)tetraacetate (EDTA.Na$, Standard volumetric Solution. 4.24.1 Preparation of the Solution Dissolve 6,33 g of disodium(ethylenedinitrilo)tetraacetate dihy- drate (CIoH1408N2Na2.2H20) in water, transfer the Solution to a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this Standard Solution corresponds approximately to 1 mg of nickel. 4.24.2 Standardization of the Solution Transfer 25,0 ml of the nicke1 reference Solution (4.24.3) to a 250 ml beaker, and add 33 ml of EDTA.Naz Solution (4.24.1). Add 15 ml of ammonium acetate Solution (4.16) and dilute to about 150 ml with water. Continue as from the third Paragraph of 7.2.5. The corresponding concentration c of the EDTA.Na* solution (4.24.1), expressed in milligrams of nicke1 per millilitre, is given by the equation bz, x 25) + fm2 x V,) C = ml is the mass, in milligrams, of nicke1 contained in 1 ml of the nicke1 reference Solution (4.24.3); m2 is the mass, in milligrams, of nicke1 corresponding to 1 ml of the zinc Standard Solution (4.25); VI is the volume, in millilitres, of the zinc Standard solu- tion (4.25) used for the titration; V2 is the volume, in millilitres, of the EDTA.Na2 Solution (4.24.1) used for the standardization. 4.24.3 Preparation of nicke1 reference Solution Weigh, to the nearest 0,l mg, 1,000 0 g of high-purity nicke1 [purity > 99,95 % (mlm)]. Dissolve in 20 ml of nitric acid (4.11). Boil t 0 remove nitrous fumes, cool, transfer quan- titatively to a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this reference Solution contains 1,0 mg of Ni. 4.25 Zinc, Standard Solution. Weigh, to the nearest 0,l mg, 1 ,114 0 g of zinc metal [purity > 99,9 % (mlm)] and transfer to a 300 ml beaker. If the zinc metal is oxidized, it should be washed with hydrochloric acid (4.9), water and acetone, respectively, and dried for 5 min at 110 OC. Add about 50 ml of water, 20 ml of hydrochloric acid (4.9) and five drops of bromine-saturated water. Cover with a watch- glass and heat to decomposition. Continue the heating until the colour of the bromine disappears, cool to room temperature and add 20 ml of acetic acid (4.3). Adjust the pH of the Solution to 6,0 -t 0,2 with ammonia Solution (4.14). Transfer quan- titatively to a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this Standard Solution corresponds to 1,0 mg of Ni and also approximately to 1 ml of the EDTA.Na2 Standard volumetric Solution (4.24). 2 SIST EN 24938:1997
iso 4938 : 1988 El 4.26 XyIenoI orange, 1 g/l Solution. Triturate 0,l g of xylenol orange (C31H28N201$Na4) with a little water to make a Paste. Dilute to 100 ml. Filter and store in an amber-coloured glass-stoppered bottle. This Solution is stable for one week. 5 Apparatus All volumetric glassware shall be grade A, in accordance with ISO 385-1, ISO 648 or ISO 1042, as appropriate. The apparatus consists of preceding Paragraph), a nd ordinary laboratory equipment 5.1 Sintered-glass filter, complying with porosity grade Pl6 of ISO 4793. 5.2 pH-meter. 5.3 Apparatus for controlled-potential electrolysis, with a saturated calomel reference electrode and a platinum elec- trode. 6 Sampling Carry out sampling in accordance with ISO 377, or appropriate national Standards for iron. 7 Procedure WARNING - Perchlorit acid vapour may Cause explo- sions in the presence of ammonia, nitrous fumes or organic material in general. 7.1 Test Portion The test Portion shall be selected so that the amount of nicke1 to be precipitated falls within the range 25 mg to 70 mg for the gravimetric finish and 25 mg to 40 mg for the titrimetric finish. For example, if 3,5 % (mlm) nicke1 is expected, weigh approx- imately 1 g of the test Sample. All weighings shall be to the nearest 0,l mg. 7.2 Determination 7.2.1 Preparation of the test Solution Place the test Portion (7.1) in a beaker of suitable capacity (e.g. 400 ml for test portions up to 2,5 g and 600 ml for test portions above 2,5 g). Add 30 ml of hydrochloric-nitric acid mixture (4.15) for test portions up to 2,5 g and 50 ml for other test por- tions. Cover the beaker with a watch-glass and heat at 50 OC to 60 OC until reaction is complete, then add 0,5 ml to 1 ml of hydrofluoric acid (4.4). Add 30 ml of perchloric acid (4.6) for test portions up to 2,5 g, and 50 ml for other test portions. Increase the temperature to approximately 180 OC and evaporate the Solution until copious white fumes of perchloric acid are evolved. Cover the beaker with a dry watch-glass and continue fuming until the chromium is completely oxidized. Remove the beaker from the hea
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