ISO-6588-2-2005.pdf
《ISO-6588-2-2005.pdf》由会员分享,可在线阅读,更多相关《ISO-6588-2-2005.pdf(14页珍藏版)》请在三一文库上搜索。
1、 Reference number ISO 6588-2:2005(E) ISO 2005 INTERNATIONAL STANDARD ISO 6588-2 First edition 2005-05-15 Paper, board and pulps Determination of pH of aqueous extracts Part 2: Hot extraction Papier, carton et ptes Dtermination du pH des extraits aqueux Partie 2: Extraction chaud ISO 6588-2:2005(E) P
2、DF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, p
3、arties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relati
4、ve to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 200
5、5 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the coun
6、try of the requester. ISO copyright office Case postale 56 CH-1211 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 2005 All rights reserved -,-,- ISO 6588-2:2005(E) ISO 2005 All rights reserved iii Contents Page Forewordi
7、v Introduction v 1 Scope1 2 Normative references .1 3 Principle.1 4 Reagents2 5 Apparatus and equipment2 6 Sampling and preparation of sample2 7 Procedure.2 8 Calculation.3 9 Precision3 10 Test report4 Annex A (informative) Preparation of some standard buffer solutions5 Bibliography .6 -,-,- ISO 658
8、8-2:2005(E) iv ISO 2005 All rights reserved Foreword ISO (the International Organization for Standardization) 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 membe
9、r 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 ISO, also take part in the work. ISO collaborates closely with the International Elec
10、trotechnical 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 committees is to prepare International Standards. Draft International Standards adopt
11、ed 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 possibility that some of the elements of this document may be the subject of paten
12、t rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 6588-2 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps. This first edition of ISO 6588-2, together with ISO 6588-1, cancels and replaces ISO 6588:1981, which has been technically revis
13、ed. The work within ISO/TC 6 has shown that the results obtained with the two parts of ISO 6588 are equivalent to those obtained in ISO 6588:1981. There are four major differences compared with the previous edition of ISO 6588:1981: a) ISO 6588 has been divided into two parts: one dealing with cold
14、extraction and the other with hot extraction; b) the determination is now carried out on an air-dry sample without determination of dry matter content, as the amount of sample is not critical; c) the extract is filtered; d) a salt solution is added to speed up the measurement. ISO 6588 consists of t
15、he following parts, under the general title Paper, board and pulps Determination of pH of aqueous extracts: Part 1: Cold extraction Part 2: Hot extraction -,-,- ISO 6588-2:2005(E) ISO 2005 All rights reserved v Introduction Kraft fibre is well known to contain ionisable groups that are fixed to or i
16、n the fibre wall. In order to fulfil the electro-neutrality, these groups are balanced by an equivalent number of positive charges, which can be either protons or various metal ions. Especially in pulp suspensions at low ionic strengths, this can give rise to a marked uneven distribution of mobile i
17、ons between the volume held by the fibre wall and the bulk suspension liquor. This means that the fibre acts as an ion exchanger. These ion-exchange phenomena can be modelled very well with the Donnan theory 2, 3. If a relatively clean pulp fibre sample, as for example bleached dried pulp, is dilute
18、d in deionised water, the result will be a pulp suspension with a very low ionic strength. In such a system, most of the cations present, including protons, will be concentrated in the water volume held by the fibre wall. If the pH is measured, it will be measured in the bulk suspension liquor. By a
19、dding salt to this kind of system, the ion exchange phenomena will be decreased and the concentration of different cations will be the same in the water held by the fibre wall and in the bulk suspension liquor. Since the process waters always contain a certain amount of ions, such a salt addition wi
20、ll give a more realistic environment when measuring the pH of relatively clean pulp samples. It is necessary to be aware of these effects when interpreting the measured pH-values of highly purified pulps. -,-,- INTERNATIONAL STANDARD ISO 6588-2:2005(E) ISO 2005 All rights reserved 1 Paper, board and
21、 pulps Determination of pH of aqueous extracts Part 2: Hot extraction 1 Scope This part of ISO 6588 specifies a method for the determination of the pH-value defined by the electrolytes extractable by hot water from a sample of paper, board or pulp. This part of ISO 6588 is applicable to all kinds of
22、 paper, board and pulp. As the quantity of extractable ionic material approaches zero, as in the case of highly purified pulps, the precision of the method becomes poor because of the difficulties encountered in making pH measurements on water containing little electrolytic material. Since the extra
23、ction in this part of ISO 6588 is performed with distilled or deionised water, the pH-value measured will sometimes be different (e.g. fully bleached pulp) from the pH-value measured under mill process conditions in which various types of process waters, e.g. chemically treated river water containin
24、g electrolytes, are used. ISO 6588-1 differs from this part of ISO 6588 only as regards the extraction conditions. No general guidance can be given as to which of the two procedures (hot or cold) is best suited in a particular situation. For cellulosic papers used for electrical purposes, the method
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ISO 6588 2005
链接地址:https://www.31doc.com/p-3778599.html