1、BS ISO26482:2010ICS 77.160NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDHardmetals Determination of leadand cadmium contentThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 28 February2010 BSI 2010ISBN 978 0
2、580 58080 2Amendments/corrigenda issued since publicationDate CommentsBS ISO 26482:2010National forewordThis British Standard is the UK implementation of ISO 26482:2010.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/65, Sintered metal components.A list of organizatio
3、ns represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS ISO
4、 26482:2010Reference numberISO 26482:2010(E)ISO 2010INTERNATIONAL STANDARD ISO26482First edition2010-02-15Hardmetals Determination of lead and cadmium content Mtaux-durs Dosage du plomb et du cadmium BS ISO 26482:2010ISO 26482:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In a
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9、11 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2010 All rights reservedBS ISO 26482:2010ISO 26482:2010(E) ISO 2010 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwid
10、e federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that
11、 committee. International organizations, governmental 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. International Standards are drafted in ac
12、cordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard req
13、uires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 26482 was prepared by Techni
14、cal Committee ISO/TC 119, Powder metallurgy, Subcommittee SC 4, Sampling and testing methods for hardmetals. BS ISO 26482:2010BS ISO 26482:2010INTERNATIONAL STANDARD ISO 26482:2010(E) ISO 2010 All rights reserved 1Hardmetals Determination of lead and cadmium content 1 Scope This International Standa
15、rd specifies a flame atomic absorption spectrometric and inductively coupled plasma spectrometric method for the determination of the lead and cadmium contents in hardmetals. The method is applicable to products having lead and cadmium contents between 0,000 1 % (mass fraction) and 0,1 % (mass fract
16、ion). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 385, Laboratory
17、glassware Burettes ISO 648, Laboratory glassware Single-volume pipettes ISO 1042, Laboratory glassware One-mark volumetric flasks 3 Principle The sample is placed in a platinum dish or polytetrafluoroethylene (PTFE) breaker. After dissociation by hydrofluoric acid, dissolve precipitated tungstic aci
18、d with sodium hydroxide solution. Mask residual cobalt with potassium cyanide and selectively separate lead and cadmium with dithizone. Then perform dilution. Perform quantitative analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectrometry (AAS).
19、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 Perchloric acid, = 1,67 g/ml. 4.2 Nitric acid (HNO3), = 1,40 g/ml, 69 % to 71 % diluted 1 + 1 with water. 4.3 Hydrofluoric acid, 40 %
20、 (mass fraction), = 1,14 g/ml or 50 % (mass fraction), = 1,17 g/ml. 4.4 Ammonium citrate, 250 g/l solution. 4.5 Sodium hydroxide, 250 g/l solution. 4.6 Potassium cyanide, 100 g/l. BS ISO 26482:2010ISO 26482:2010(E) 2 ISO 2010 All rights reserved4.7 Ammonia solution. 4.8 Dithizone, in chloroform, 0,0
21、2 %. Dissolve 0,2 g of dithizone in 1 000 ml of chloroform. Prepare fresh, or store in a brown bottle. 4.9 Dithizone, in chloroform, 0,005 %. Dissolve 0,05 g of dithizone in 1 000 ml of chloroform. Prepare fresh, or store in a brown bottle. 4.10 Standard lead stock solution, Pb(II)= 1 mg/ml. Weigh t
22、o the nearest 0,000 1 g, 0,5 g of high-purity lead min. 99,95 % (mass fraction) and dissolve in 30 ml of nitric acid (1 + 1) (4.2). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric flask. Keep the flask at the same temperature as the flask was calibrated at. D
23、ilute to the mark with water and mix. The purchase and use of certified stock solutions is possible. 4.11 Standard cadmium stock solution, Cd(II)= 1 mg/ml. Weigh to the nearest 0,000 1 g, 0,5 g of high-purity cadmium min. 99,95 % (mass fraction) and dissolve in 30 ml of nitric acid (1 + 1) (4.2). Co
24、ol and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric flask. Keep the flask at the same temperature as the flask was calibrated at. Dilute to the mark with water and mix. 4.12 Mixed analyte standard solution, Pb(II)100 g/ml; Cd(II)100 g/ml. To a 250 ml one-mark volum
25、etric flask containing 30 ml of concentrated nitric acid, add 25 ml each of 1 000 mg/l stock standard solutions (4.10 and 4.11) of Pb and Cd, using a burette accurately. Make up to the mark with water and mix. 5 Apparatus Usual laboratory apparatus and in particular the following. 5.1 Inductively co
26、upled plasma atomic emission spectrometry (ICP-AES). The ICP-AES used will be satisfactory after optimizing according to the manufacturers instructions. 5.2 Flame atomic absorption spectrometer (FAAS). The FAAS used will be satisfactory after optimizing according to the manufacturers instructions. 5
27、.3 Burette, of capacity 50 ml, according to ISO 385, class A. 5.4 Pipette, of capacities 1 ml, 3 ml, 5 ml, 25 ml, according to ISO 648, class A. 5.5 One-mark volumetric flasks, of capacities 100 ml, 250 ml, 500 ml, according to ISO 1042, class A. 5.6 Beaker, of capacities 250 ml, 1 000 ml, made of s
28、ilica or borosilicate glass. 5.7 Platinum dish, of capacities 50 ml, 100 ml. 5.8 PTFE beaker, of capacities 50 ml, 100 ml. BS ISO 26482:2010ISO 26482:2010(E) ISO 2010 All rights reserved 36 Procedure 6.1 Test portion Weigh, to the nearest 0,000 1 g, 1 g of the test sample and transfer it to a platin
29、um dish. Rinse the sample into the bottom of the dish by wetting the rim of the dish using a wash bottle containing distilled water. 6.2 Attack and extraction Add 15 ml of nitric acid (4.2) and 5 ml of hydrofluoric acid solution (4.3) and shake until exhaustion of NOxgas (red-brown color). Heat to c
30、omplete dissociation. Control the heating temperature to prevent boiling of the solution. After dissociation of the sample, add 10 ml of perchloric acid (4.1) and keep heating until generation of a white gas of perchloric acid and until the final volume of sample is 5 ml to 10 ml. Cool the platinum
31、dish with the sample to room temperature, add 20 ml of nitric acid (1 + 1), cover with watch glass and heat. Add 20 ml of ammonium citrate solution (25 %) (4.4) and heat again. In the warm platinum dish, stirring with a PTFE rod, put (little by little) 40 ml of sodium hydroxide (25 %)1)to the time o
32、f colour change (yellow to pink)2). Transfer the sample solution to a 250 ml glass beaker and cool it to room temperature. Add 3 ml of potassium cyanide (10 %) (4.6) and adjust the pH of the solution to 9,2 0,2 with ammonium hydroxide (1 + 1) (4.7) or nitric acid (1 + 1) solution. Transfer the adjus
33、ted solution into a separation funnel by washing the beaker wall with distilled water. In case the pH of the solution that dissolves the sample is over 8, add 10 % potassium cyanide. Put 20 ml of dithizone (0,02 %) (4.8) in the separation funnel and stir fully for 5 min. Stand until separation of th
34、e dithizone layer and water layer occurs. Transfer the lower layer of dithizone to a new beaker. Add 20 ml of dithizone (0,02 %) again and stir it fully for 5 min. Add 10 ml of dithizone (0,005 %) to the water layer of the separation funnel and wash by stirring fully for 5 min. Leave to stand to all
35、ow separation of the layers. Add the dithizone layer to the preceding dithizone layer. Heat the solution at 60 C to 80 C in a warm bath until complete evaporation of chloroform occurs. Add 10 ml of nitric acid and 5 ml of perchloric acid to the dried glass beaker and insert a glass rod into the beak
36、er. Cover with a watch glass and heat until generation of a white gas of perchloric acid. After the generation of a white gas of perchloric acid, dry and thicken it. After cooling it at normal temperature, transfer it to a 100 ml volumetric flask, dilute it with water and mix it. 6.3 Blank test Carr
37、y out blank tests in parallel with the determination, following the same procedure and using the same quantities of all the reagents, but omitting the test portion. 1) Add to dissolve precipitated yellow tungstate to a pink colour. 2) In removing the watch glass from the platinum dish to add the rea
38、gent, the inner side should be washed with distilled water. BS ISO 26482:2010ISO 26482:2010(E) 4 ISO 2010 All rights reserved7 Analytical parameters 7.1 Atomic absorption spectrometer (AAS) wavelength 7.1.1 The spectral lines specified in Table 1 should be used in the analysis. Table 1 Spectral line
39、s Wavelength Pb nm Wavelength Cd nm 283,3 228,8 7.1.2 A fuel-lean air/acetylene flame shall be used. 7.2 Inductively coupled plasma (ICP) wavelength The spectral lines specified in Table 2 should be used in the analysis. Table 2 Spectral lines Wavelength Pb nm Wavelength Cd nm 220,3 228,8 8 Preparat
40、ion of calibration curve 8.1 Using burettes or pipettes, transfer 0 ml, 1 ml, 3 ml and 5 ml of lead and cadmium standard solution (100 mg/l, see 4.12) to 100 ml volumetric flasks. Add 15 ml of nitric acid, dilute to the mark by adding distilled water and mix well. 8.2 Spray the solutions into an ind
41、uctively coupled argon plasma or atomic absorption spectrometer serially and plot calibration curves by measuring the emission strength at the wavelengths noted in 7.1 and 7.2. 8.3 After plotting the calibration curve, measure each element in the test solution and blank solution. 9 Calculation The P
42、b or Cd content, expressed in milligrams per kilogram (mg/kg), in the sample, is given by Equations (1) and (2): ()12PbVwm= (1) ()12CdVwm= (2) where wPbis the Pb content in the sample, in milligrams per kilograms (mg/kg); wCdis the Cd content in the sample, in milligrams per kilograms (mg/kg); BS IS
43、O 26482:2010ISO 26482:2010(E) ISO 2010 All rights reserved 51is the mass concentration of the element in the test solution, in milligrams per litre (mg/l); 2is the mass concentration of the reagent blank solution, in milligrams per litre (mg/l); V is the dilution volume of the test solution, in mill
44、ilitres (ml); m is the mass of sample, in grams (g). 10 Test report The test report shall include at least the following information: a) all information necessary for the identification of the sample, the laboratory and the date of analysis; b) the method used by reference to this International Stan
45、dard; c) the results and the form in which they are expressed; d) the analytical line used; e) any unusual features noted during the determination; f) any operation not specified in this International Standard, or any optional operation which may have influenced the results. BS ISO 26482:2010ISO 264
46、82:2010(E) 6 ISO 2010 All rights reservedAnnex A (informative) Hardmetals Determination of lead and cadmium content A.1 Introduction There is a significant matrix effect from the primary ingredient of a coexisting element in the analysis of trace elements in an ultra-hard metal sample by AAS or ICP,
47、 so direct measurement from a sample solution cannot provide good precision. A reproducibility test of the solvent extraction method that separates and concentrates Pb and Cd from the primary ingredient to examine the optimum analysis method and the reproducibility has been conducted. A.2 Repeatabil
48、ity results of hardmetals Test samples Due to a lack of certified reference materials (CRM) of ultra-hard metal that ensure concentrations of Pb and Cd, a composition of test samples of tungsten (W) metal equal to that of the common sample given in Table A.1 has been made. Also Pb oxide and Cd oxide
49、 were added to high-purity tungsten carbon (WC) and cobalt (Co) powders for levels of Pb and Cd. The results for the test samples are summarized in Table A.1. The result of reviewing the uniformity on these reference materials and testing repeatability is given in Table A.2. Table A.1 Chemical composition of test samples WC Co Pb content Cd content Sample % (mass fraction) % (mass fraction) mg/kg mg/kg HM 1 94 6 200 100 HM 2 94 6 400 200 Table A.2 Repeatability results (n = 6) Pb content mg/kg C
