692 (ISO International Standard INTE RNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAR OPTAHW3AUMH HO CTAHAAPTW3AUWWORGANISATION INTE RNATIONALE DE NORMALISATION Pulps - Determination of alkali solubility Pates -- Détermination de la solubilite dans les solutions d'hydroxyde de sodium Second edition - 1982-11-15 UDC 676.014.362 Ref. No. 1SO 692-1982 (E) 2-1982 (E) Descriptors : paper pulps, chemical analysis, solubility, sodium hydroxide, volumetric analysis. ISO 692-1 Price based on 4 pages ted without license from IHS Not for Resale Foreword ISo (the international Organization for Standardization) is a worldwide federation of national standards institutes (ISO member bodies). The work of developing Inter- national Standards is carried out through IsO technical committees. Every member body interested in a subject for which a technical committee has been set up 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. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. International Standard ISO 692 was developed by Technical Committee ISO/TC 6, Paper, board and pulps. This second edition was submitted directly to the Iso Council, in accordance with clause 6.11.2 of part 1 of the Directives for the technical work of ISO. It cancels and replaces the first edition (i.e. ISo 692-1974), which had been approved by the member bodies of the following countries : Australia Germany, F. R. Romania Belgium India South Africa, Rep. of Brazil Iran Spain Canada Ireland Sweden Chile Switzerland Israel Colombia Italy Turkey United Kingdom Czechoslovakia Japan Denmark New Zealand USA Egypt, Arab Rep. of Norway Yugoslavia Finland Poland France Portugal The member body of the following country had expressed disapproval of the docu- ment on technical grounds : Netherlands @ International Organization for Standardization, 1982 Printed in Switzerland Copyright International Organization for Standardization Not for Resale ISO 692-1982 (E) INTERNATIONAL STANDARD Pulps -- Determination of alkali solubility Principle Introduction The object of both this International Standard and ISO 699, Treatment of the pulp with sodium hydroxide solution and ox- Determination of alkali resistance, is to permit the idation of the dissolved organic matter with potassium Pulps study of the behaviour of pulps in the presence of alkali solu- dichromate. Titration of the excess potassium dichromate and tions, but their fields of application are different : while this In- calculation of the amount of cellulose equivalent to the ternational Standard describes the volumetric determination of potassium dichromate consumed. the alkali-soluble constituents of the pulp and is appied preferably to the control of bleached pulps, iso 699 describes the gravimetric determination of the alkali-insoluble consti- Reagents tuents of the pulp and applies to all categories of pulps. Use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. Scope and field of application Sodium hydroxide, solution of known concentraticn, 5.1 containing less than 1 g of sodium carbonate per litre (see the This International Standard specifies a method for the deter- note), for example : mination of the solubility of pulp in cold sodium hydroxide solu- tions of various and fixed concentrations. The sodium hydrox- 5,39 ± 0,03 mol/l solution, containing 18,0 ± 0,1 g ide concentrations most are 18and frequently used sodium hydroxide 100 g of solution of per 10 % (m/m). (020 = 1,197 2 g/ml), equivalent to 215,5 ± 1,0 g of sodium hydroxide per litre; The method is mainly intended for the investigation of bleached pulps, but may, however, nim pasn aq osje 2,77 ± 0,03 mol/l solution, containing 10,0 ± 0,1 g for example in