1、BRITISH STANDARD BS 6200-3.16.1: 1986 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.16 Determination of lead Subsection 3.16.1 Carbon steels and low alloy steels: gravimetric method UDC 669.1:543.21:546.815BS6200-3.16.1:1986 This British Standard
2、, having been prepared under the directionof the Iron and Steel Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 30September1986 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft for comment
3、 85/37326 DC ISBN 0 580 15284 7 Foreword This Subsection of BS 6200 has been prepared under the direction of the Iron and Steel Standards Committee. It supersedes method1 for the determination of lead in BSI Handbook No.19, to which it is technically equivalent. BS 6200 is a multipart British Standa
4、rd covering all aspects of the sampling and analysis of iron, steel and other ferrous metals. A list of contents, together with general information, will be given in Part1, to be published in due course. A British Standard does not purport to include all the necessary provisions of a contract. Users
5、 of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 and2, an inside back cover and a back
6、 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. Amendments issued since publication Amd. No. Date of issue CommentsBS6200-3.16.1:1986 BSI 09-1999 i Contents Page Foreword In
7、side front cover 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Sampling 1 6 Procedure 1 7 Calculation and expression of results 2 8 Test report 2 Table 1 Precision data 2 Publications referred to Inside back coverii blankBS6200-3.16.1:1986 BSI 09-1999 1 1 Scope This Subsection of BS 6200 desc
8、ribes a gravimetric method for the determination of lead in steel. The method is applicable to carbon steels and lowalloy steels containing chromium, copper, molybdenum and nickel. Tin contents up to0.25%m/m and tungsten contents up to2% m/m do not interfere. The method is applicable to lead content
9、s exceeding0.05% m/m. NOTEThe titles of the publications referred to in this Subsection of BS6200 are listed on the inside back cover. 2 Principle Lead is precipitated as sulphide with hydrogen sulphide from dilute hydrochloric acid solution. The precipitate is filtered off, washed, dissolved in aci
10、d and the lead precipitated as lead molybdate from ammoniacal tartrate solution. The determination is completed gravimetrically. 3 Reagents During the analysis, use only reagents of recognized analytical reagent grade and only distilled water or water of equivalent purity. 3.1 Acetic acid, glacial,
11、density ( )1.048 g/mL to1.050 g/mL. 3.2 Ammonia solution, 0.91g/mL, diluted1+1. 3.3 Ammonium acetate, 20g/L solution. Dissolve20g of ammonium acetate in water, makejust acid to litmus paper with glacial acetic acid (3.1), dilute to1L and mix. 3.4 Ammonium chloride 3.5 Ammonium molybdate, 50 g/L solu
12、tion. Dissolve50g of ammonium molybdate (NH 4 ) 6 Mo 7 O 24 .4H 2 O in water, dilute to1L and mix. 3.6 Hydrochloric acid, 1.16g/mL to1.19g/mL. 3.7 Hydrofluoric acid, 40% m/m. 3.8 Hydrogen sulphide gas, from a generator or cylinder. 3.9 Hydrogen sulphide-hydrochloric acid wash To 900mL of water add5m
13、L of hydrochloric acid(3.6), dilute to1L and pass a rapid stream of hydrogen sulphide gas (3.8) through the solution for not less than10min. 3.10 Nitric acid, 1.42g/mL, diluted2+3. 3.11 () Tartaric acid, 500g/L solution. Dissolve500g of tartaric acid in water, dilute to1L and mix. 4 Apparatus Use or
14、dinary laboratory apparatus. 5 Sampling Sampling shall be carried out in accordance with BS1837. NOTEBS6200-2 “Methods of sampling and sample preparation”, which will supersede BS1837, is currently in preparation. On its publication, this Subsection will be amended to include a requirement to sample
15、 in accordance with BS6200-2. 6 Procedure 6.1 Test portion Weigh, to the nearest0.001g, a test portion of10g. 6.2 Blank test In parallel with the determination and following the same procedure, carry out a blank test using the same quantities of all the reagents. 6.3 Determination Place the test por
16、tion in a650mL conical beaker. Add30mL of water and70mL of hydrochloric acid(3.6). Cover the beaker and heat gently until solvent action ceases. Evaporate to about20mL, transfer to a steam bath and continue the evaporation almost to dryness; then cool. Add200mL of water and heat until the soluble sa
17、lts are dissolved. If the salts do not dissolve readily on boiling add1mL to2mL of hydrochloric acid (3.6). Dissolve any tungstic acid in5mL of hydrofluoric acid (3.7). Filter through a paper-pulp pad into a650mL conical beaker and wash with hot water. Dilute the filtrate to about400mL, cool to room
18、 temperature and pass through a rapid stream of hydrogen sulphide gas (3.8) for20min. Filter through apaper-pulp pad and wash with hydrogen sulphide-hydrochloric acid wash solution (3.9). Transfer the filter and precipitate to the650mL conical beaker in which the precipitation was made, add20mL of n
19、itric acid (3.10) and heat until the sulphides are dissolved. Dilute to50mL, filter through a12.5cm open texture ashless filter paper into a400mL beaker and wash with hot water. To the filtrate add5mL of hydrochloric acid (3.6), cool and add5mL of tartaric acid solution (3.11).BS6200-3.16.1:1986 2 B
20、SI 09-1999 Neutralize with ammonia solution (3.2), add5mL excess and dilute to150mL with hot water. Add10g of ammonium chloride (3.4), heat to boiling and add dropwise10mL of ammonium molybdate solution (3.5). Continue boiling for10min, add5mL of ammonia solution (3.2) and allow tosettle for4h or ov
21、ernight. Filter through a paper-pulp pad and wash with hot ammonium acetate solution (3.3). Transfer the filter and precipitate to a shallow porcelain crucible, dry and ignite at as low a temperature as possible until carbonaceous matter is removed. Finally, heat at a temperature not exceeding650 C.
22、 Cool, transfer the residue to a150mL beaker, add5mL of nitric acid (3.10). Warm to dissolve the soluble salts and dilute with50mL of water. Filter through a paper-pulp pad into a650mL conical beaker, wash with hot water, cool and add0.5mL of tartaric acid solution (3.11). Neutralize with ammonia so
23、lution (3.2), add5mL excess and dilute to150mL with hot water. Add10g of ammonium chloride (3.4), heat to boiling and add dropwise1mL of ammonium molybdate solution (3.5). Continue boiling for10min, add5mL of ammonia solution (3.2) and allow tosettle for4h or overnight. Filter through a paper-pulp p
24、ad and wash with hot ammonium acetate solution (3.3). Transfer the filter and precipitate to a shallow porcelain crucible, dry and ignite at as low a temperature as possible until carbonaceous matter is removed. Finally, heat at a temperature not exceeding650 C. Cool and weigh as lead molybdate. 7 C
25、alculation and expression of results 7.1 Calculation Calculate the lead content, expressed as a percentage by mass, from the equation where 7.2 Precision A planned trial of this method was carried out involving from nine to11 laboratories and six levels of lead in leaded carbon and low-alloy steels.
26、 The mean results for each laboratory given in the original report 1)have been treated statistically to obtain values for between-laboratory agreement. It is not possible, in the absence of the individual results, to calculate the values of repeatability and reproducibility as defined in BS5497-1. T
27、he results showed a linear relationship between lead content and between-laboratory agreement as summarised inTable 1. The difference between the mean results of two laboratories found on identical test material will exceed the agreement levels given inTable 1 on average not more than once in20 case
28、s in the normal and correct operation of the method. 8 Test report The test report shall contain the following information: a) identification of the sample; b) the method of analysis used, by reference to this Subsection of BS6200; c) the results obtained, and the form in which they are expressed; d
29、) any particular details noted during the determination; e) any operations not specified in this standard, or any optional operations which may have influenced the results. Table 1 Precision data m 1 is the mass (in g) of lead molybdate precipitated from the test solution; m 0 is the mass (in g) of
30、residue from the blank solution (6.2); m is the mass (in g) of the test portion (6.1). Lead content 56.44 m 1 m 0 () m - = 1) See Journal of the Iron and Steel Institute,1959,193,350. Lead content % m/m 0.05 0.100 0.15 0.20 0.25 0.30 Agreement 0.010 0.011 0.013 0.015 0.017 0.018BS6200-3.16.1:1986 BS
31、I 09-1999 Publications referred to BS 1837, Methods for the sampling of iron, steel, permanent magnet alloys and ferro-alloys. BS 5497, Precision of test methods. BS 5497-1, Guide for the determination of repeatability and reproducibility for a standard test method. BSI Handbook No. 19, Methods for
32、the sampling and analysis of iron, steel and other ferrous metals 2) . Journal of the Iron and Steel Institute,1959,193,350. 2) Referred to in the foreword only.BS 6200-3.16.1: 1986 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsib
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