1、BRITISH STANDARD BS 6783-3: 1986 EN 27520:1991 ISO 7520:1985 Incorporating Amendment No. 1 Sampling and analysis of nickel, ferronickel and nickel alloys Part 3: Method for determination of cobalt in ferronickel by flame atomic absorption spectrometry ISO title: Ferronickel Determination of cobalt c
2、ontent Flame atomic absorption spectrometric method The European Standard EN 27520:1991 has the status of a British Standard UDC 669.1524-198:620.1:543.442:546.73BS6783-3:1986 This British Standard, having been prepared under the directionof the Non-ferrous Metals Standards Committee, waspublished u
3、nder the authorityof the Board of BSI andcomes into effect on 31December 1986 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference NFM/10 Draft for comment 84/39892 DC ISBN 0 580 15522 6 Committees responsible for this British Standard The preparation of
4、this British Standard was entrusted by the Non-ferrous Metals Standards Committee (NFM/-) to Technical Committee NFM/10, upon which the following bodies were represented: British Non-ferrous Metals Federation British Steel Industry Engineering Equipment and Materials Users Association Ministry of De
5、fence Process Plant Association Stainless Steel Fabricators Association of Great Britain Coopted members Amendments issued since publication Amd. No. Date of issue Comments 6992 February 1992 Indicated by a sideline in the marginBS6783-3:1986 BSI 10-1999 i Contents Page Committees responsible Inside
6、 front cover National foreword ii 1 Scope and field of application 3 2 References 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Sampling and samples 3 7 Procedure 4 8 Expression of results 5 9 Special cases 5 10 Test report 5 Table Results of statistical analysis 5 Publications referred to Inside bac
7、k coverBS6783-3:1986 ii BSI 10-1999 National foreword This Part of BS 6783 has been prepared under the direction of the Non-ferrous Metals Standards Committee. It is identical with ISO 7520:1985 “Ferronickel Determination of cobalt content Flame atomic absorption spectrometric method” published by t
8、he International Organization for Standardization (ISO). In 1991 the European Committee for Standardization (CEN) accepted ISO7520:1985 as European Standard BS 27520:1991 without any modifications. At present this British Standard consists of nine Parts all concerned with analysis of nickel, ferroni
9、ckel and nickel alloys. Further International Standards are in preparation on sampling and analysis of nickel, ferronickel and nickel alloys and, when available, these will be published as further Parts of this British Standard. Terminology and conventions. The text of the International Standard has
10、 been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is
11、 current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “Part of BS 6783”. In British Standards it is current practice to use the symbol “L” for litre (and in its submultiples)
12、 rather than “l”. The Technical Committee has reviewed the provisions of ISO 385-1 and ISO 648, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. ISO 385-1 is related to BS 846:1985 “Specification for burettes” and ISO 648 is
13、related to BS 1583:1986 “Specification for one-mark pipettes”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity fr
14、om legal obligations. Cross-references International Standards Corresponding British Standards ISO 1042:1983 BS 1792:1982 Specification for one-mark volumetric flasks (Identical) ISO 5725:1981 BS 5497 Precision of test methods Part 1:1979 Guide for the determination of repeatability and reproducibil
15、ity for a standard test method (Technically equivalent) ISO 6352:1985 BS 6783 Sampling and analysis of nickel, ferronickel and nickel alloys Part 2:1986 Method for determination of nickel in ferronickel (dimethylglyoxime gravimetric method) (Identical) Summary of pages This document comprises a fron
16、t cover, an inside front cover, pages i and ii, theEN title page, pages 2 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDA
17、RD NORME EUROPENNE EUROPISCHE NORM EN 27520 November 1991 UDC 669:1524-198:620.1:543.422:546.73 Descriptors: Ferroalloys, ferronickel, chemical analysis, determination of content, cobalt, atomic absorption spectrophotometry English version Ferronickel Determination of cobalt content Flameatomic abso
18、rption spectrometric method (ISO 7520:1985) Ferro-nickel Dosage du cobalt Mthodepar spectromtrie dabsorption atomique dans la flamme (ISO 7520:1985) Ferronickel Bestimmung des Cobaltgehaltes Atomabsorptions-Spektralfotometrisches Verfahren (ISO 7520:1985) This European Standard was approved by CEN o
19、n 1991-11-06. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving 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
20、 obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official 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 the Central
21、 Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Com
22、mittee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN 1991 Copyright reserved to all CEN members Ref. No. EN 27520:1991 E2 blankEN27520:1991 BSI 10-1999 3 1 Scope and field of application This Internation
23、al Standard specifies a flame atomic absorption spectrometric method for the determination of the cobalt content of ferronickel in the range 0,025 to 2,5% (m/m). 2 References ISO 385-1, Laboratory glassware Burettes Part1: General requirements. ISO 648, Laboratory glassware One-mark pipettes. ISO 10
24、42, Laboratory glassware One-mark volumetric flasks. ISO 5725, Precision of test methods Determination of repeatability and reproducibility by inter-laboratory tests. ISO 6352, Ferronickel Determination of nickel content Dimethylglyoxime gravimetric method. 3 Principle Dissolution of a test portion
25、in a nitric acid-hydrochloric acid mixture. Precipitation of silica by dehydration in perchloric acid. Removal of silica by filtration. Addition of lanthanum for elimination of potential interferences. Determination of cobalt by atomic absorption spectrometry in an air-acetylene flame at a wavelengt
26、h of 240,7 nm. NOTEThis analysis can be carried out on solutions which have been used for the determination of nickel by ISO 6352. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Hydrochloric acid, 20= 1,19
27、g/ml. 4.2 Hydrochloric acid, 20= 1,19 g/ml, diluted 1 + 9. 4.3 Nitric acid, 20= 1,41 g/ml, diluted 1 + 1. 4.4 Perchloric acid, 20= 1,61 g/ml 72% (m/m). 4.5 Hydrofluoric acid, 20= 1,14 g/ml, diluted 1 + 1. WARNING Hydrofluoric acid is extremely irritating and corrosive to skin and mucous membranes, p
28、roducing severe skin burns which are slow to heal. In case of skin contact wash well with water and seek medical advice. 4.6 Lanthanum, solution, containing 200 g of La perlitre. Weigh 250 g of lanthanum chloride hexahydrate (LaCl 3 6H 2 O) and transfer to a 600 ml beaker. Add25 ml of hydrochloric a
29、cid (4.1) and 300 ml of water. Stir to complete dissolution. Filter, if necessary, into a 500 ml one-mark volumetric flask, make up to the mark with water and mix. 4.7 Nickel plus iron, matrix solution, containing12g of Ni and 28 g of Fe per litre. 4.7.1 Weigh 12,0 g of high purity nickel powder con
30、taining less than 0,001% (m/m) cobalt into an800 ml beaker. Add 50 ml of water and 50 ml of nitric acid ( 20= 1,41 g/ml). When the initial reaction subsides, stir and heat to complete dissolution. Dilute to about 250 ml with water. 4.7.2 Weigh 28,0 g of high purity iron powder containing less than 0
31、,001% (m/m) cobalt into an800 ml beaker. Add 100 ml of hydrochloric acid diluted 1 + 1. Carefully add 50 ml of nitric acid ( 20 =1,41 g/ml) and heat to complete dissolution and oxidation of iron. Dilute to about 250 ml. 4.7.3 Carefully combine the nickel solution (4.7.1) with the iron solution (4.7.
32、2). Filter into a 1 000 ml one-mark volumetric flask, make up to the mark with water and mix. 4.8 Cobalt, standard solution, corresponding to0,500 g of Co per litre. Weigh, to the nearest 0,001 g, 0,500 g of high purity99,9% (m/m) Co, minimum cobalt powder, transfer to a 600 ml beaker and add 40 ml
33、of nitric acid (4.3). Heat to complete dissolution, boil gently to expel oxides of nitrogen, cool and transfer to a1000 ml one-mark volumetric flask containing160 ml of nitric acid (4.3). Make up to the mark with water and mix. 1 ml of this standard solution contains 0,500 mg ofCo. 5 Apparatus Ordin
34、ary laboratory glassware, and 5.1 Atomic absorption spectrometer, equipped with a laminar flow burner for an air-acetylene flame and a cobalt hollow cathode lamp. 5.2 Burette, of capacity 50 ml, graduated in divisions of 0,1 ml, in accordance with ISO 385-1, class A. 5.3 Glass beakers, of capacity 6
35、00 ml, clean, unetched and flat bottomed. 5.4 Pipettes, of capacities 25 and 50 ml, in accordance with ISO 648, class A. 5.5 Volumetric flasks, of capacities 250; 500; and1000 ml, in accordance with ISO 1042, class A. 5.6 Polytetrafluoroethylene (PTFE) beaker, of capacity 600 ml, for samples with a
36、high silicon content. 6 Sampling and samples 6.1 Sampling and preparation of the laboratory sample shall be carried out by normal agreed procedures or, in case of dispute, by the relevant International Standard.EN27520:1991 4 BSI 10-1999 6.2 The laboratory sample normally is in the form of millings,
37、 drillings or granules and no further preparation of the sample is necessary. 6.3 If it is suspected that the laboratory sample is contaminated with oil or grease from the milling or drilling process, it shall be cleaned by washing with high purity acetone and drying in air. 6.4 If the laboratory sa
38、mple contains particles or pieces of widely varying sizes, the test portion should be obtained by riffling. 7 Procedure WARNING Fuming perchloric acid is a powerful oxidant and can cause an explosive mixture when in contact with organic materials. All evaporations should be done in fume cupboards su
39、itable for use with perchloric acid. 7.1 Test portion Weigh, to the nearest 0,001 g, 3,9 to 4,1 g of the laboratory sample and transfer to a glass beaker(5.3). 7.2 Blank test Carry out a blank test in parallel with the determination, following the same procedure and using the same quantities of all
40、the reagents. 7.3 Preparation of test solution 7.3.1 Dissolve the test portion (7.1) by adding 25 ml of water followed by 50 ml of nitric acid (4.3). Cover the beaker with a watch-glass and heat gently, if necessary, to complete dissolution. NOTEFor ferronickel samples containing more than 1% (m/m)
41、silicon, use a polytetrafluoroethylene beaker (5.6). Attack the test portion by adding successively 25 ml of water, 40 ml of nitric acid(4.3) and 10 ml of hydrochloric acid (4.1). To obtain complete dissolution of the sample, add, at the end of effervescence, 10 ml of hydrofluoric acid (4.5) and 40
42、ml of perchloric acid (4.4). Heat until evolution of fumes of perchloric acid. Allow to cool and transfer the solution quantitatively to a glass beaker (5.3). Heat at 260 C until abundant white fumes are obtained. Reflux at this temperature for 20 min and proceed as directed in 7.3.2, “Remove the be
43、aker . . .”. 7.3.2 When the metal is dissolved, add 40 ml of perchloric acid (4.4) and heat at 260 C until abundant white fumes are obtained. Reflux at this temperature for 20 min. Remove the beaker from the hotplate and allow to cool. Add 20 ml of hydrochloric acid (4.1) and 200 ml of warm water. F
44、ilter off the silica using a medium porosity filter paper, collecting the filtrate in a 1 000 ml one-mark volumetric flask. Rinse the beaker and wash the silica precipitate three times with hydrochloric acid diluted 1 + 9 and four times with warm water. Discard the silica precipitate. Add 50 ml of l
45、anthanum solution (4.6) to the filtrate, make up to the mark with water and mix thoroughly (test solution A). 7.4 Preparation of calibration solutions 7.4.1 Set A 7.4.1.1 Transfer six 50,0 ml volumes of the nickel plus iron matrix solution (4.7) to six 150 ml beakers. 7.4.1.2 Add, using a burette (5
46、.2), 0; 1,0; 2,0; 3,0; 5,0; and 10,0 ml respectively of the cobalt standard solution (4.8). Add 20 ml of perchloric acid (4.4) and heat just to the liberation of white fumes. Cool, add50 ml of water and transfer quantitatively into a 500 ml one-mark volumetric flask containing10ml of hydrochloric ac
47、id (4.1). Add25ml of lanthanum solution (4.6), make up to the mark with water and mix. 7.4.2 Set B 7.4.2.1 Transfer six 5 ml volumes of the nickel plus iron matrix solution (4.7) to six 150 ml beakers. 7.4.2.2 See 7.4.1.2. 7.5 Calibration and determination 7.5.1 Expected cobalt contents 0,025 to0,25
48、% (m/m) Carry out the determination on test solutionA(7.3.2) and the set of calibration solutionsA (7.4.1). 7.5.1.1 Set the required instrument parameters of the atomic absorption spectrometer according to the manufacturers instructions using a cobalt hollow cathode lamp at a wavelength of 240,7 nm.
49、 7.5.1.2 Light the burner and adjust the air and acetylene flows to obtain a slightly oxidizing clear non-luminescent flame while aspirating water. 7.5.1.3 Aspirate test solution A (7.3.2) into the flame and note the absorbance reading.EN27520:1991 BSI 10-1999 5 7.5.1.4 Aspirate water and check that the reading returns to zero. 7.5.1.5 Aspirate the set of calibration solutionsA(7.4.1) in order of increasing instrument response and note the absorbance readings. Flush the system with water between eac
