746 NTERNATIONAL STANDARD Tso INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ·MEKIYHAPOIHA OPFAHH3AIM HO CTAHIAPTM3ALIWH.ORGANISATION INTERNATIONALE DE NORMALISATION Sodium carbonate for industrial use -- Determination of matter insoluble in water at 50 °C Carbonate de sodium a usage industriel -- Détermination de I'insoluble dans I'eau a 5o °c First edition - 1976-02-01 UDC 661.833.622 : 543.721 Ref. No. ISO 746-1976 (E) Descriptors : sodium carbonate, chemical analysis, determination of content, insoluble matter. no Price based on 2 pages Copyright International Organization for Standardization d without licensefrom 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 Internationa! 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. Prior to 1972, the results of the work of the Technical Committees were published as Iso Recommendations; these documents are now in the process of being transformed into Internationat Standards. As part of this process, Technica! countries : Austria South Africa, Rep. of India Belgium Italy Spain Switzerland Brazil Japan Turkey Chile Korea, Rep. of Czechoslovakia Netheriands United Kingdom Egypt, Arab Rep. of New Zealand U.S.A. U.S.S.R. France Poiand Germany Yugoslavia Portugal Hungary Romania No Member Body expressed disapproval of the Recommendation. No Member Body disapproved the transformation of ISO/R 746 into an International Standard. @ International Organization for Standardization, 1976 : Printed in Switzerland Copyright International Organization for Standardization efrom IHS ISO 746-1976 (E) INTERNATIONAL STANDARD Sodium carbonate for industrial use - Determination of matter insoluble in water at 50 °C 1 SCOPE AND FIELD OF APPLICATION 6.2 Determination This International Standard specifies a method for the determination of the matter insoluble in water at 50 °c of time, while stirring, to a beaker of suitable capacity (for sodium carbonate for industrial use. example: 600 ml) _containing 200 ml of water heated to approximately 50 °c. Place the crucible (5.1) in the oven (5.2) controlled at 2 REFERENCES 110 ± 5 °c. After drying for 1 h, remove it, allow to cool in a desiccator to ambient temperature and weigh to the IsO 739, Sodium carbonate for industrial use - Preparation nearest 0,000 1 g. and storage of test samples. Filter the decanted sodium carbonate solution through ISO745, Sodium carbonate for industrial use the tared filter crucible maintaining a reduced pressure Determination of loss of mass and of non-volatile matter by means of a filter pump or a vacuum pump. Wash the at 250 °C. insoluble matter onto the sintered disk with water at approximately 50 °c until 20 ml of the filtrate show no colour on addition of 2 drops of the phenolphthalein (4.1) 3 PRINCIPLE Place the filter crucible containing the insoluble matter in the oven controlled at 110± 5 °c and leave to dry for 1 h. Dissolution of a test portion and filtration of the solution After cooling, in a desiccator to ambient temperature, through a tared filter. Washing of the insoluble matter at weigh to the nearest 0,000 1 g. approximately 5o°c until the washings are no longer alkaline. Drying of the residue and weighing. 7 EXPRESSION OF RESULTS The matter insoluble in water at 50°c, expressed as a 4 REAGENTS percentage by mass, is given by the formula : During the analysis, use only reagents of recognized .100 m1 × analytical reagent grade and only