1、CEN EN*LO*L36 89 3404589 OOL4504 3 EUROPEAN STANDARD NORME EUROPEENNE EUROPISCHE NO.RM EN 10 136 January 1989 UDC 669.14 : 543 A22 : 546.74 Key words: Iron- and steel products, steels, cast iron, chemical analysis, determination of content, nickel, atomic absorption spectrophotometry, flame photomet
2、ry. Eng1 ish version Chemical analysis of ferrous materials Determination of nickel in steels and irons Flame atomic absorption spectrometric method Analyse chimique des matriaux sidrurgiques - Dosage du nickel dans les aciers et les fontes Mthode par spectromtrie dabsorption Flammenatomabsorptionss
3、pektrometrisches atomique dans la flamme Verfahren Chemische Analyse von Eisenwerkstoffen - Bestimmung von Nickel in Stahl This European Standard was accepted by CEN on 15 January 1989. CEN members are bound to comply with the requirements of the CENKENELEC Rules which stipulate the conditions for g
4、iving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Central Secretariat or to any CEN member. This European Standard exists in the official
5、versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to CEN Central Secretariat has the same status as the official versions. CEN members are the national standards organizations of Austria
6、, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue Br
7、derode 2, B-1000 Brussels O CEN 1989 Copyright reserved to all CEN members - -_ _ Ref. No. EN 10 136:1989 E Page 2 EN 10 136 Brief history This European Standard takes over the content of EURONORM 136-85 “Chemical analysis of ferrous materials - Determination of nickel in steels and irons - Flame at
8、omic absorption spectrometric method“, prepared by ECISS/TC 20 “Methods of chemical analysis“; the Secretariat of which is allocated to the Dansk Standardiseringsrad (DS). It has been submitted to the CEN Formal Vote following the decision of the Coordinating Commission (COCOR) of the European Commi
9、ttee for Iron and Steel Standardization on 1987-1 1 -24/25. It has been adopted and ratified by CEN BT on According to the Common CENKENELEC Rules, following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
10、 Luxemburg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Note in clauses 1 and 9 EURONORM shall read EUROPEAN STANDARD. 1988-11-05. CEN EN*30*13b 89 m 3404589 003450b 7 m Page 3 EN 10 136 Chemical analysis of ferrous materials Determination of nickel in steels and ir
11、ons Flame atomic absorption spectrometric method CONTENTS 1. SCOPE AND FIELD OF APPLICATION 7. PROCEDURE 2. REFERENCE 7.2 Blank test 3. PRINCIPLE 7.4 Establishment of the calibration graph 4. REAGENTS 8. EXPRESSION OF RESULTS 7.1 Test portion 7.3 Determination 5. APPARATUS 9. TEST REPORT 6. SAMPLING
12、 ANNEX: Precision data 1. SCOPE AND FIELD OF APPLICATION This EURONORM specifies a method for the determination of nickel in steels and irons by means of flame atomic absorption spectrometry. The method is applicable to steels and irons with nickel contents of 0.003 to 2.0% (m/m). 2. REFERENCE EURON
13、ORM 18 - Selection and preparation of samples and test pieces for steel and iron and steel products. General guidelines for the application of flame atomic absorp- tion spectrometric methods are in course of preparation. 3. PRINCIPLE Dissolution of a test portion in a mixture of appropriate acids an
14、d fuming with perchloric acid. Spraying of the solution into an air-acetylene flame. Determi- nation of the nickel by means of the spectrometric measure- ment of the atomic absorption of the 232.0 nm or 352.5 nm line emitted by a nickel hollow cathode lamp. The instrument is calibrated by addition o
15、f a nickel standard solution to a similar matrix to that of the test solution. NOTE - At the wavelength of 352.5 nm the signal-to- noise ratio is higher than at a wavelength of 232.0 nm. Generally, use of the 352.5 nm line will lead to a better reproducibility. However, as the sensitivity at 352.5 n
16、m is less than the sensitivity at 232.0 nm, with some instruments the use of the longer wavelength will be impossible when analysing low nickel contents. 4. REAGENTS During the analysis use only reagents of recognized analytical 4.1 Iron of high purity, with a nickel content reagent quality and havi
17、ng a very low nickel content, and only distilled water or water of equivalent purity. Carefully check the nickel content of all reagents. If possible, use only freshly prepared distilled or deionized water. 0.0005% (dm) 4.2 Hydrochloric acid-nitric acid mixture Mix three volumes of hydrochloric acid
18、, p I. 19 g/ml approxi- mately, one volume of nitric acid, p 1.40 g/ml approximately CEN EN*10*13b 89 9 3404589 0014507 9 9 Page 4 EN 10 136 and two volumes of water. This mixture is to be prepared immediately before use. 4.3 Nitric acid-perchloric acid mixture Mix 100 ml of nitric acid, p1.40 g/mi
19、approximately with 800 ml of perchloric acid, p 1.54 g/ml approximately. Dilute to 1 1 with water and mix. NOTE - Perchloric acid 1.67 g/ml approximately) may also be used. 100 nil of perchloric acid (j 1.54 g/mi approxi- mately) is equivalent to 79 ml of perchloric acid p 1.67 g/mi approximately).
20、Ordinary laboratory equipment and 4.4 Nickel stock solution, corresponding to 1 mg of nickel per ml approximately Weigh, to the nearest 0.001 g, about 0.5 g of high purity nickel (2 99.9% pure). Transfer the weighed mass to a 400 ml beaker and dissolve in 25 ml of nitric acid 1.40 g/ml approximately
21、 diluted 1 + i (v/v). Boil to remove oxides of nitrogen. Cool and transfer the solution to a 500 ml volu- metric flask, dilute to the mark with water and mix. Calculate the concentration of nickel in this stock solution, in mg/ml. 4.5 Nickel reference solution, corresponding to 40 pg of nickel per m
22、l approximately Transfer 10.0 ml of nickel stock solution (4.4) to a 250 ml volumetric flask, dilute to the mark with water and mix. Calculate the concentration of nickel in the reference solution. in ,ug/ml. 5. APPARATUS mean absorbency of the most concentrated calibration solu- tion. For example,
23、if the top and bottom calibration solutions 5* absorption spectrometer; a hol- represent 0.1% and 0.01% nickel in the sample, the precision called for (as two standard deviations) would be 0.002% and 0.001% nickel respectively, assuming curve linearity. low cathode lamp; supplies Of air and acetylen
24、e sufficiently pure to give a steady clear fuel-lean flame, free from water and oil, and free from nickel 5.1.2 Additional performance requirements The atomic absorption spectrometer used will be satisfactory if after optimization according to 7.3.4 the limit of detection and characteristic concentr
25、ation are in reasonable agreement with the values given by the manufacturer and it meets the following performance requirements. 5.1.1 Minimum precision The standard deviation of 10 measurements of the absorb- ency of the most concentrated solution shall not exceed 1.0% of the mean absorbance. The s
26、tandard deviation of IO measurements of the absorb- ance of the least concentrated calibration solution (excluding the zero calibration solution) shall not exceed 0.5% of the It is also desirable that the instrument should conform to the following additional performance requirements. (a) Characteris
27、tic concentration - The characteristic concen- tration for nickel in a matrix similar to the final test solution shall be better than O. 10 .ug/ml. (b) Limit of detection - The limit of detection of nickel in a matrix similar to the final test solution shall be better than O. i 5 pg/ml. 5.2 Ancillar
28、y equipment A strip chart recorder and/or digital readout device is recom- mended to evaluate the criteria in 5.1 and for all subsequent measurements. 6. SAMPLING Sampling shall be carried out in accordance with EURONORM 18. 7. PROCEDURE WARNING - Perchloric acid vapours may cause explosions in the
29、presence of ammonia, nitrous fumes or organic matter in general. Always use a specially designed fume-hood. 7.1 Test portion Weigh the mass (ni) indicated below to the nearest 0.001 g: rn = 1 g f 5%. CEN EN*30*33b I39 3404589 0034508 O W 7.2 Blank test With each analytical run, carry out an analysis
30、 on a reagent blank in parallel with the test portion analysis, using identical reagents, conditions, analytical procedures and dilutions throughout. 7.3 Determination 7.3.1 Preparation of the test solution Place the test portion (7.1) in a 250 ml beaker. Add 10 ml of hydrochloric acid-nitric acid m
31、ixture (4.2). Heat gently until the reaction ceases. Add 15 mi of nitric acid-perchloric acid mixture (4.3) and heat until dense white fumes of perchloric acid appear. Con- tinue heating for one minute and allow to cool. NOTE - If the test portion is readily soluble in the nitric acid-perchloric aci
32、d mixture (4.3), the addition of hydro- chloric acid-nitric acid mixture (4.2) can be omitted. In that case the test portion is dissolved in the nitric acid-perchloric acid mixture (4.3) and the solution thus obtained is heated as described above. Dissolve in 25 ml of water by heating gently. Cool a
33、gain and transfer the solution to a 100 ml volumetric flask, dilute to the mark with water and mix. This is the test solution. If some residue has been left in the solution due to silicon, tungsten, niobium or tantalum, filter the solution through a dry, me- dium textured filter paper, discarding th
34、e first runnings. If the expected nickel content of the test sample exceeds O. 1% (m/m). dilute the solution as follows: Transfer 25.0 ml of the solution to a 500 ml volumetric flask, dilute to the mark with water and mix. NOTE - If the solution has to be diluted to give the test solution, the blank
35、 test solution (7.2) must be diluted in the same way. 7.3.2 Preparation of the calibration solutions Place 10 g of iron (4. i) in a 800 ml beaker. Add 100 ml of hydrochloric acid-nitric acid mixture (4.2) and heat gently to dissolve the iron. Add I50 ml of nitric acid-perchloric acid mixture (4.3) a
36、nd heat until dense white fumes of perchloric acid appear. Con- tinue heating for one minute and allow to cool. Dissolve in 100 ml of water by heating gently. Cool again and transfer the solution to a 250 ml volumetric flask, dilute to the mark with water and mix. 7.3.2.1 Nickel cotitetit 0.1% (dtn)
37、 Transfer a series of 25.0 ml aliquots of the iron solution to 100ml volumetric flasks, add to each flask by means of a burette or pipette respectively O, 2.5, 5.0, 10.0, 15.0, 20.0 and 25.0 ml of nickel reference solution (4.9, dilute to the mark with water and mix. 7.3.2.2 Nickel coilletit 0.1 to
38、2.0% (dm) Transfer 25.0 ml of the iron solution to a 500 ml volumetric flask, dilute to the mark with water and mix. From this solution transfer 25.0 ml aliquots to 100 ml volumetric flasks. Page 5 EN 10 136 Add to each flask by means of a burette or pipette respec- tively O, 2.5, 5.0, 10.0, 15.0, 2
39、0.0 and 25.0 ml of nickel reference solution (4.3, dilute to the mark with water and mix. NOTE - 1 ml of nickel reference solution (4.5) is approxi- mately equivalent to 0.004% (m/m) in the sample in the case of 7.3.2.1 and 0.08% (m/m) in the sample in the case of 7.3.2.2. 7.3.3 Adjustment of atomic
40、 absorption spectrometer (5. i) Type of lamp: Wavelength : Flame: Air-acetylene clear fuel-lean Lamp current - nickel response Slit width Follow manufacturers Nickel hollow cathode. 232.0 nm or 352.5 nm. flame adjusted for maximum recommendations. NOTE - The manufacturers recommendations should be c
41、losely followed and particular attention is drawn to the following safety points: (a) the explosive nature of acetylene and regulations concern- (b) the need to shield the eyes of the operator from UV (c) the need to keep burner head clear of deposits. A badly (d) make sure that the liquid trap is f
42、illed with water. ing its use; radiation by means of tinted glass: clogged burner may cause a flash back; 7.3.4 Optimization of the atomic absorption spectrometer Follow the manufacturers instructions for preparing the in- strument for use. When the current to the lamp, the wavelength and flow of ga
43、s have been adjusted and the burner lit, spray water until the indication has stabilized. Set the absorbance value to zero. Choose a damping setting or integration time to give a signal steady enough to fulfil the precision requirements (5. I). Adjust the flame to be clear fuel-lean and the burner h
44、eight to about 1 cm below the light path. Spraying, alternately. the high. and zero calibration solutions, adjust the gas flow and burner position (horizontally, vertically and rotationally) until the difference in absorbance between the calibration solutions is at a maximum. Evaluate the criteria o
45、f 5.1.1 to ensure that the instrument is suitable for the determination. settings 7.3.5 Atomic absorption measurements Set the scale expansion so that the top calibration solution gives nearly full scale deflection. Aspirate the calibration solutions in ascending order repetitively until each gives
46、the acceptable precision (see 5. I. I), thus showing that the instrument has achieved stability. Select two calibration solutions, one having an absorbency just lower than the test solution and one just higher. Aspirate these first in ascending order, then in descend- ing order, with the test soluti
47、on as the middle solution in each case, measuring the absorbency in relation to water. Aspirate the complete range of calibration solutions again. It is recognized that these procedures cannot be followed with automatic instruments which accept two calibration solutions Page 6 EN 10 136 only. In thi
48、s case, it is suggested that the two sandwiching solutions should not be used for the primary calibration but should be analysed alternately with the test solution. Obtain the net mean absorbance of each calibration solution by subtracting the mean absorbance of the zero calibration solution. Obtain
49、 the mean absorbance of the test solution and the mean absorbance of the reagent blank solution. Convert the mean absorbances of the test solution and of the reagent blank solution to micrograms of nickel per millilitre by means of the calibration graph (7.4). 7.4 Establishment of the calibration graph it is necessary to draw up a new calibration graph for each series of determinations, and for the range of nickel contents expected. Prepare a calibration graph by plotting the net mean absorb- ance velues of the calibration solutions against micrograms of nickel per m
