ISO 10238 pdf download

ISO 10238 pdf download.Carbonaceous materials used in the production of aluminium — Pitch for electrodes — Determination of sulfur content by an instrumental method 1 Scope This International Standard describes a method for determining the sulfur content of pitch used in the production of aluminium. The method is applicable to pitches of both coal tar and petroleum origin, provided that they contain between 0,1 % and 4,0 % by mass of sulfur. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes of openings. ISO 3696, Water for analytical laboratory use — Specification and test methods . ISO 4793, Laboratory sintered (fritted) filters — Porosity grading, classification and designation. ISO 6257, Carbonaceous materials used in the production of aluminium — Pitch for electrodes — Sampling. 3 Principle A known mass of the sample is burned in a stream of oxygen at a temperature of 1 350 °C. The oxides of sulfur formed, together with any chlorine present, are absorbed in neutral hydrogen peroxide and determined volumetrically. A correction is made to take account of the chlorine content of the sample. Aluminium oxide is added to the sample to prevent the retention of sulfur in the ash. 4 Reagents Unless otherwise specified, use reagents of analytical reagent grade and water conforming to grade 3 of ISO 3696. 4.1 Disodium tetraborate solution, c(½Na 2 B 4 O 7 ·1 0H 2 O) = 0,025 mol/l. 4.2 Sulfuric acid solution, c(½H 2 SO 4 ) = 0,025 mol/l.4.4 Screened indicator, consisting of equal volumes of a) and b) prepared as follows and mixed immediately before use: a) 0,1 25 g of methyl red dissolved in 1 00 ml of 95 % by volume ethanol solution; b) 0,083 g of methylene blue dissolved in 1 00 ml of 95 % by volume ethanol solution. Store in a dark...