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1、BRITISH STANDARD BS ISO 779:2005 Paper, board and pulp Determination of acid-soluble iron ICS 85.040; 85.060 ? Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 779:2005 This British Standard was published under the authority of the Sta
2、ndards Policy and Strategy Committee on 31 March 2006 BSI ISBN 0 580 47985 4 National foreword This British Standard reproduces verbatim ISO 779:2005 and implements it as the UK national standard. It supersedes BS ISO 779:2001 which is withdrawn. The UK participation in its preparation was entrusted
3、 to Technical Committee PAI/11, Methods of test for paper, board and pulps, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred t
4、o in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions
5、of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or pr
6、oposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 6, an inside back cover and a back
7、cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Reference number ISO 779:2005(E
8、) INTERNATIONAL STANDARD ISO 779 Third edition 2005-05-01 Paper, board and pulp Determination of acid-soluble iron Papier, carton et pte Dtermination de la teneur en fer soluble dans lacide BS ISO 779:2005 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled C
9、opy, (c) BSI ii Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internati
10、onal 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 committee. International organizations, governmental and non-governmental, in liaison with IS
11、O, 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 accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical co
12、mmittees 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 requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the
13、 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 779 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps. This third edition cancels and replaces the seco
14、nd edition (ISO 779:2001), of which it constitutes a minor revision. Apart from minor editorial modifications, only the title has been changed, to be consistent with ISO 1830:2005, and to make a distinction with ISO 17812 (to be published) which specifies the method to determine the total mass fract
15、ion of calcium, manganese, iron and copper. The first edition of this International Standard included the photometric procedure as well as the procedure based on atomic absorption spectroscopy. In the second edition, the photometric procedure was deleted, as it is now seldom used, and the scope was
16、enlarged to include paper and board in addition to pulp. BS ISO 779:2005 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv Introduction This International Standard corresponds to ISO 777 ?1? and ISO 778 ?2? in order to make it possible to p
17、erform the final measurement of all three elements on the same solution. BS ISO 779:2005 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 1 Paper, board and pulp Determination of acid-soluble iron WARNING The method specified in this Internat
18、ional Standard involves the use of some hazardous chemicals and of gases that can form explosive mixtures with air. Care must be taken to ensure that the relevant precautions are observed. 1 Scope This International Standard specifies the procedure for the determination of acid-soluble iron by atomi
19、c absorption spectrometry or by plasma emission spectrometry. It is applicable to all kinds of paper, board and pulp. It specifies a method to determine the acid-soluble part of the incineration residue, i.e. that part of the ignition residue obtained after incineration which is soluble in hydrochlo
20、ric acid. If the residue is completely soluble, the result obtained by the procedure specified in this International Standard is taken as the total amount of iron in the sample. 2 Normative references The following referenced documents are indispensable for the application of this document. For date
21、d references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 186, Paper and board Sampling to determine average quality ISO 287, Paper and board Determination of moisture content Oven-drying method ISO 638
22、, Pulps Determination of dry matter content ISO 1762, Paper, board and pulps Determination of residue (ash) on ignition at 525 C ISO 7213, Pulps Sampling for testing 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 mass fraction of iron amount
23、 of the element iron in the solution obtained after incineration of the specimen at 525 C and treating the residue with 6 mol/l hydrochloric acid, as specified in this International Standard BS ISO 779:2005 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled
24、Copy, (c) BSI 2 4 Principle A test portion is incinerated at 525 C and the residue is treated with 6 mol/l hydrochloric acid. The test solution is aspirated into an acetylene/dinitrogen monoxide or acetylene/air flame and the mass fraction of iron is determined by one of the following procedures: ?
25、measurement of the absorption of the 248,3 nm line emitted by an iron hollow-cathode lamp, or ? measurement of the absorption of the 248,3 nm line emitted by plasma emission spectrometry. 5 Reagents and materials Use only chemicals of recognized analytical grade and only distilled or deionized water
26、. 5.1 Hydrochloric acid, about 6 mol/l. Dilute 500 ml of hydrochloric acid (density 1,19 g/ml) in 500 ml of water. 5.2 Iron stock solution, 100 mg/l of Fe. Dissolve 100 mg of pure iron wire in the smallest quantity possible of hydrochloric acid (density 1,19 g/ml) in a 1 000 ml volumetric flask. Dil
27、ute with water to the mark and mix. 1 ml of this stock solution contains 0,10 mg of Fe. 5.3 Iron standard solution, 10 mg/l of Fe. Transfer 100 ml of the iron stock solution (5.2) to a 1 000 ml volumetric flask and add 200 ml of hydrochloric acid (5.1). Dilute with water to the mark and mix. 1 ml of
28、 this standard solution contains 0,01 mg of Fe. The solution is not stable. Commercially available, certified standard iron solutions may be used. 5.4 Acetylene gas and/or dinitrogen monoxide gas, of a grade suitable for atomic absorption spectrometry. WARNING Acetylene gas forms explosive mixtures
29、with air. 5.5 Appropriate gas for the plasma spectrometer (6.4). Argon is usually recommended as a carrier gas. 6 Apparatus and equipment Ordinary laboratory equipment. Clean all equipment in 0,1 mol/l hydrochloric acid. 6.1 Filter paper, ash free, particle retention 20 ?m to 25 ?m. 6.2 Dishes, of p
30、latinum or quartz. 6.3 Atomic absorption spectrometer, with a burner for dinitrogen monoxide/acetylene or air/acetylene and with a hollow-cathode lamp for iron. NOTE A multi-element lamp may be used. 6.4 Inductively coupled plasma spectrometer. BS ISO 779:2005 Licensed Copy: sheffieldun sheffieldun,
31、 na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 7 Sampling and preparation of sample If the analysis is being made to evaluate a lot of paper, board or pulp, the sample shall be selected in accordance with ISO 186 or ISO 7213, as relevant. If the analysis is made on another typ
32、e of sample, report the source of the sample and, if possible, the sampling procedure. Select the specimens so that they are representative of the sample received. A sufficient amount of sample shall be collected to allow for at least duplicate determinations. Avoid cut edges, punched holes and othe
33、r parts where metallic contamination may have occurred. Prepare a test specimen by tearing at least 30 g of small pieces from various parts of the sample. This amount is sufficient for the duplicate determinations as prescribed in Clause 8. 8 Procedure 8.1 Incineration and dissolution of the residue
34、 Carry out the procedure in duplicate. Air-dry the specimen in the laboratory atmosphere until it reaches moisture equilibrium. Determine the moisture content on a separate air-dried portion as specified in ISO 287 or ISO 638, as relevant. Weigh this portion at the same time as the test portion, use
35、d for incineration. Carry out ashing of the test portion, as described in ISO 1762. A portion of 2 g to 5 g is usually sufficient. Carry out the dissolution of the ash under a fume hood. To avoid splattering, carefully moisten the ash with water and add 5 ml of hydrochloric acid (5.1) to the dish. E
36、vaporate to dryness on a boiling-water bath or equivalent device. Repeat this procedure. For samples with a high carbonate content, more than 10 ml of acid (2 5 ml) may be needed, for example 20 ml (2 10 ml). Add 2,5 ml of the hydrochloric acid (5.1) in order to dissolve the residue. If necessary, h
37、eat the dish covered by a watch glass for a few minutes. Using the filter paper (6.1), filter the contents of the dish into a 25 ml volumetric flask. To ensure that the transfer is complete, add another portion of 2,5 ml of acid to the dish and heat again. Filter this last portion of acid into the m
38、ain portion in the volumetric flask with the aid of some water. Fill up to the mark and mix. This is the test solution. 8.2 Blank Run a blank with the same quantity of each of the chemicals as those added to the incineration residue, but without any residue. 9 Preparation of calibration solutions It
39、 is important that the acid concentration is the same in the calibration and in the test solution since the acid concentration influences the signal. From the iron standard solution (5.3), prepare at least three calibration solutions, and in addition one zero solution, for the construction of the ca
40、libration graph. (The zero solution is similar to the calibration solutions, but contains no added iron. Do not confuse it with the blank.) NOTE Not more than two calibration solutions are needed for plasma emission spectrometry. BS ISO 779:2005 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27
41、 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 10 Determination Carry out the spectrometric measurement of the calibration solutions, including the zero solution, the test solution and the blank solution. Operate the instrument as instructed by the manufacturer. The solutions may contain lan
42、thanum or caesium, if the same solutions are used for the determination of calcium. These salts do not interfere with the determination of iron, but the same amounts of salts shall be added to the calibration solutions. If any value obtained exceeds the range covered by the calibration solutions, th
43、e measurement shall be repeated with a more dilute test solution. Add acid, caesium solution or lanthanum solution as required. Most instruments have a system for automatic evaluation of results. If the instrument has no automatic evaluation system, construct the calibration graph by plotting the ab
44、sorbance, corrected for the blank, against the concentration of iron in milligrams per litre.Then read the iron concentration in the test solution from the calibration graph. 11 Calculation Calculate the mass fraction of iron from the expression Fe Fe fV m r w ? = where wFeis the mass fraction of ir
45、on in the sample, in milligrams per kilogram; rFe is the iron concentration in the test solution, as obtained from the calibration plot corrected for the blank, in milligrams per litre; V is the volume, in millilitres, of the original test solution (standard volume ? 25 ml); m is the mass of sample
46、taken, oven-dry basis, in grams; f is the dilution factor; f ? 1, unless the original test solution has been diluted. Calculate the mean with two significant figures. 12 Precision 12.1 General A study 1) gave the following results. 12.2 Repeatability A sample of uncoated paperboard was analysed in o
47、ne laboratory nine times. The mean found was 13 mg/kg, and the coefficient of variation (CV) was 8 %. NOTE As the study comprises only one sample and one laboratory, the result is only a rough estimation of the repeatability. 1) Study made by SCAN-test in 1996. BS ISO 779:2005 Licensed Copy: sheffie
48、ldun sheffieldun, na, Mon Nov 27 08:30:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 5 12.3 Reproducibility Four samples were analysed in eight laboratories. The results in Table 1 were obtained for the mean and the coefficient of variation (CV). Table 1 Mean CV Sample type mg/kg % Bleached pulp 3,6
49、 45 Coated paperboard 430 19 Uncoated paperboard 13 28 Copy paper 180 4 NOTE The high CV-values are possibly due to an uneven distribution of iron in the sample. 13 Test report The test report shall include the following information: a) reference to this International Standard; b) date and place of testing; c) complete identification of the sample tested; d) the result, expressed as indicated in Clause 11; e) any departure from the procedure described in this International Standard o