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1、BRITISH STANDARD BS ISO 11480:1997 Pulp, paper and board Determination of total chlorine and organically bound chlorine ICS 85.040; 85.060 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11480:1997 This British Standard, having been p
2、repared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 February 1998 BSI 04-1999 ISBN 0 580 29272 X National foreword This British Standard reproduces verbatim ISO 11480:1997 and implements it
3、as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee PAI/11, Methods of test for paper, board and pulps, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiri
4、es on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The Britis
5、h Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British
6、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 from legal obligations. Summary of pages This document comprises a front co
7、ver, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 5 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. Amendments issued sinc
8、e publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11480:1997 BSI 04-1999i Contents Page National forewordInside front cover Forewordiii Text of ISO 114801 Licensed Copy: sheffieldun sheffieldun, na, Mo
9、n Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11480:199
10、7 ii BSI 04-1999 Contents Page Forewordiii 1Scope1 2Normative references1 3Definitions1 4Principle1 5Chemicals and reagents1 6Precautions2 7Apparatus2 8Pretreatment of the sample2 9Extraction with acid nitrate solution3 10Combustion3 11Blanks3 12Checks3 13Calculation4 14Precision4 15Test report4 16I
11、nterference from bromine compounds4 Annex A (informative) Laboratory manuals 5 Table 14 Table 24 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11480:1997 BSI 04-1999iii Foreword ISO (the International Organization for Standardizatio
12、n) is a worldwide 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 rep
13、resented on that 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. Draft International Stand
14、ards 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. International Standard ISO 11480 was prepared by Technical Committee ISO/TC 6, Paper, board and pu
15、lps. Annex A of this International Standard is for information only. Descriptors: Paper, paperboards, paper pulps, chemical analysis, determination of content, chlorine, combustion analysis, coulometric methods. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontro
16、lled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11480:1997 BSI 04-19991 1 Scope This International Standard specifies the determination of total and organically bound chlorine in pulp, paper and board. It i
17、s applicable to all types of pulp, paper and board. The lower limit of the determination is about 20 mg/kg. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the e
18、ditions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of curren
19、tly valid International Standards. ISO 186:1994, Paper and board Sampling to determine average quality. ISO 287:1985, Paper and board Determination of moisture content Oven-drying method. ISO 638:1978, Pulps Determination of dry matter content. 3 Definitions For the purposes of this International St
20、andard, the following definitions apply. 3.1 total chlorine the total amount of the element chlorine present 3.2 organically bound chlorine the amount of organically bound chlorine present 4 Principle Determination of the chlorine content of the sample by combustion under controlled conditions in a
21、quartz tube at high temperature. The combustion gases are fed through an electrolyte solution where all chlorine, now transformed to hydrogen chloride, is absorbed and determined by microcoulometry. For determination of the organically bound chlorine content, the inorganic chlorine compounds are ext
22、racted with dilute nitric acid before combustion. NOTE 1If determination of organically bound chlorine is not required, the extraction with nitric acid is omitted. NOTE 2Any bromine present will interfere and cause a positive error. For details, see clause 16. 5 Chemicals and reagents All chemicals
23、used should be of analytical reagent grade. Water for the preparation of solutions, or used in the procedure, shall be distilled water of high purity or equivalent. High blanks (see clause 11) can be due to impure water. The water can then be purified by treating it with activated carbon (5.4). 5.1
24、Acid nitrate solution, stock solution. Dissolve 17 g of sodium nitrate (NaNO3) in distilled water. Add 1,4 ml of nitric acid (HNO3) density 1,40 g/ml, and dilute to 1 litre with distilled water. (This solution is only required for the determination of organically bound chlorine.) 5.2 Acid nitrate so
25、lution, working solution. Dilute 50 ml of the stock solution (5.1) to 1 litre with distilled water. (This solution is only required for the determination of organically bound chlorine.) 5.3 Sulfuric acid (H2SO4), density 1,84 g/ml. 5.4 Activated carbon, for adsorption of water-soluble organic materi
26、al in the determination of organically bound chlorine. (Suitable carbon is provided by manufacturers of combustion apparatus.) 5.5 Electrolyte solution, for use in the microcoulometer. Dilute 75 ml of glacial (98 %) acetic acid (CH3COOH) to 100 ml with water. NOTEAddition of sodium perchlorate (NaCl
27、O4) and sulfamic acid (NH2SO3H) to the absorption solution is recommended by some manufacturers of microcoulometers. Such additions are optional. One manufacturer recommends a solution prepared by dissolving 1,35 g of sodium acetate (NaCH3COO) in 850 ml of glacial acetic acid and diluting to 1 000 m
28、l with water. 5.6 Hydrochloric acid, c(HCl) = 0,010 0 mol/l. 5.7 2-Chlorobenzoic acid reference solution. Dissolve 110,3 mg of ClC6H4COOH in distilled water and dilute to 100 ml in a volumetric flask. This solution contains 250 mg of organically bound chlorine per litre. Dilute the solution as requi
29、red before use. 5.8 Compressed gases. Oxygen is required for the combustion. Other gases may also be required in order to control the combustion. It is essential that all gases used are free from chlorine and bromine in any form. NOTEIt has been reported that chlorinated solvents have been used to c
30、lean the gas containers. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11480:1997 2 BSI 04-1999 6 Precautions Chlorine compounds in small quantities are present almost everywhere, in chemicals, on the surfaces of the equipment, on t
31、he skin and in the laboratory air. It is therefore of utmost importance to take every measure to avoid contamination of samples and solutions. Especially, the risk of contamination from the laboratory air should be observed. Such contamination can come from reagents (solvents) stored in the laborato
32、ry as well as from outdoor sources, for example a bleaching plant. Clean all equipment before use with dilute nitric acid and flush with pure water. 7 Apparatus Of the items listed below, items 7.1 through 7.4 are required only if organic chlorine has to be determined. Item 7.7 is required only if t
33、otal chlorine has to be determined. 7.1 Conical flasks, 250 ml, of chemically resistant glass, with standard tapered glass stoppers or PTFE-lined screw caps. 7.2 Shaker for the flasks (7.1) giving their contents a circular motion. Its power shall be adjustable so that the contents are kept in motion
34、 without reaching the stopper. 7.3 Filtering device for vacuum filtration on filters of diameter about 25 mm. 7.4 Filters, polycarbonate, nominal pore width 0,4 m, diameter to fit the filtering device (7.3) and having a maximum chlorine content of 0,5 g. Alternatively, specially designed filtering c
35、ups of heat-resistant glass or ceramic material may be used. NOTEIf high blank values (11) are obtained, the reason may be contaminated filters. They should be washed before use with stock solution (5.1) and then with water. 7.5 Combustion apparatus, consisting of a quartz tube connected to a cell f
36、or microcoulometric titration (7.6). A multizone furnace can heat the middle section of the tube to at least 950 C and preferably 1 000 C. A boat of quartz or other heat-resistant material fits into the tube. The boat can be moved from the cold end of the tube to its hot section. The tube shall be w
37、ide enough to accommodate a boat loaded with a filter (7.4). The apparatus has an oxygen supply and some means for maintaining a constant flow of oxygen through the tube. The oxygen stream may be diluted with an inert gas, such as argon or nitrogen. The combustion gases are fed through the microcoul
38、ometric cell for continuous titration of chloride ions. If required, a heated washing device containing sulfuric acid (5.3) for cleaning and drying the gas stream may be inserted between the outlet of the combustion tube and the cell. 7.6 Microcoulometer, enabling the determination of 2 g of chlorid
39、e ion with a coefficient of variation of less than 10 %, calculated from repeated determinations of chloride ion. 7.7 Sample cups, capacity about 1 ml, of quartz or other heat-resistant material, designed to fit into the sample boat. The use of these cups is optional. 8 Pretreatment of the sample Ke
40、ep samples protected from ambient air in polyethylene bags or in packages of aluminium foil. Use protective gloves whenever handling the sample. Check that no chlorine-containing material is transferred from the gloves to the sample. Air-dry wet pulp at a temperature not exceeding 40 C. Using a sepa
41、rate sample, determine the dry matter content as described in ISO 638 or ISO 287, as relevant. Tear or cut the sample into small pieces using tweezers or scissors. The size of the pieces has to be adapted to the nature of the sample as well as to the dimensions of the combustion equipment. Split sam
42、ples of pulp or paperboard to ensure complete soaking of the sample during the extraction step. If the soaking is incomplete, the results for organically bound chlorine may be too high. Grind samples of coated or multi-ply paper and paperboard in a small mill, Wiley type or similar. The mill must no
43、t be used for other purposes in order to avoid contamination of samples. Clean the mill carefully after each use. The total amount of sample required depends on its chlorine content and is limited by the dimensions of the combustion apparatus. Normally the amount of sample required for each single d
44、etermination is between 10 mg and 60 mg. For the determination of both parameters, a total of four sample portions is required. Weigh each sample portion to the nearest 0,1 mg. All samples should have approximately the same mass. Of the four samples, two are taken for determination of total chlorine
45、, and two are extracted with acid nitrate solution. NOTEIf determination of organically bound chlorine is not required, proceed directly to clause 10. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:21:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 11480:1997 BSI 04-19993 9 Extractio
46、n with acid nitrate solution Transfer the two duplicate samples to 250 ml conical flasks with glass stoppers. Add 100 ml of the acid nitrate solution (5.2) and 15 mg of activated carbon (5.4) to each flask. At the same time, start two blanks without any sample. Close the flasks and shake them vigoro
47、usly to wet the sample entirely. Place the flasks in a mechanical shaking machine and shake them for at least 1 h. When analysing coated or filled papers containing large amounts of carbonate pigments, check that the mixture in the flask is still acid. If not, acidify the mixture by adding more of t
48、he acid nitrate solution (5.2). Using the filtering device (7.3), filter the contents of the flasks on a polycarbonate filter or in a filtering cup (7.4). Rinse the flask and the sides of the filtering funnel with small portions of the acid nitrate solution (5.2), about 25 ml in all. Finally wash wi
49、th a small portion of water. Apply suction until excess liquid has been removed. NOTEDrawing large volumes of air through the filter should be avoided, as this may lead to contamination from halogen compounds present in the ambient atmosphere. On the other hand, any excess washing solution present in the filter may result in condensation of water in the combustion tube. Condensed water in the tube may interfere with the combustion (clause 10). If the filter is too dry it may ignite in the drying zone of the oven, which might lead to a low result. 10 Combusti