BS 6043-1.1:2002 pdf download – Methods of sampling and test for carbonaceous materials used in aluminium manufacture — Part 1: Electrode pitch — Section 1.1: Sampling

BS 6043-1.1:2002 pdf download – Methods of sampling and test for carbonaceous materials used in aluminium manufacture — Part 1: Electrode pitch — Section 1.1: Sampling 4 General procedures and precautions 4.1 Sampling methods Manual and automated sample-taking are equally acceptable. Details of the methods employed shall be described in the sampling report (see clause 1 0). 4.2 Contamination of sample or of pitch being sampled The sampling procedure shall not cause contamination of the sample or of the pitch being sampled. Sample containers, sampling apparatus and any ancillary gear shall be dry. Sample containers, sampling apparatus, any ancillary gear, the hands and gloves and the protective clothing of the sampler shall be clean. Pitch undergoes slow surface oxidation in the presence of air. Finely divided products, because of their large surface area per unit mass, may show a significant rise in softening point even if stored for only a short time. It is recommended therefore that finely divided reference samples be prepared for storage by melting and resolidifying as follows. a) Place a sufficient amount of the powdered sample in a suitable container with a loose-fitting lid in an oven controlled at approximately above the expected softening point of the pitch. Leave in the oven for at this temperature. After heating, the surface of the melt should be smooth, shiny and free of skin. b) If the surface of the melt is covered with froth, suggesting the presence of water, discard it and prepare another melt using a further portion of the sample which has first been dried by allowing it to stand in an evacuated desiccator in the presence of a suitable desiccant for approximately . c) Pour the molten pitch without turbulence, so as to avoid entrapping air bubbles, into an air-tight metal container, allowing it to solidify and seal the container. d) Note any froth formation during melting in the sample report and, in such cases; retain a separate portion of the finely-divided sample, stored in a sealed air-tight container, for the determination of water content. If a sample container is opened, it shall be securely closed again as soon as possible and any damaged sealing rings shall be replaced. 4.3 Sampling for the determination of water content of pitch in solid form For bulk shipments of solid pitch, a series of spot samples shall be taken for determination of water content, either from the conveying...