BS ISO 7404-4:2017 pdf download – Methods for the petrographic analysis of coals Part 4: Method of determining microlithotype, carbominerite and minerite composition 1 Scope This document specifies a method,using a graticule with 20 crossline intersections,for determining theproportions of microlithotypes, carbominerite and minerite in coals. It applies only to determinationsmade on polished particulate blocks using reflected white light (about 400 nm to 700 nm).Additionalblue, blue-violet or UV light excitation (365 nm to 440 nm) for better identification of liptinite influorescence may be used especially at low rank coals. 2Normative references The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document.For dated references, only the edition cited applies. Forundated references, the latest edition of the referenced document(including any amendments) applies.ISO 7404-1,Methods for the petrographic analysis of coals — Part 1: Vocabulary ISO 7404-2,Methods for the petrographic analysis of coals — Part 2:Methods of preparing coal samples 3Terms and definitions For the purposes of this document, the terms and definitions given in IlSO 7404-1 and the following apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: -ISO online browsing platform: available at http://www.iso.org/obp -IEC Electropedia: available at http://www.electropedia.org/ 3.1 point observation of a portion of the particulate block through the eyepiece graticule made during theanalysis Note 1 to entry: The allocation of a point to a particular microlithotype, or to carbominerite or minerite, isdetermined by the macerals and/or mineral matter present at the 20 intersections of the graticule.A point is onlycounted if at least 10 intersections fall on a particle. 4 Principle Examination by using a reflected light microscope and point count procedure of a representative sampleof coal prepared as a particulate block as described in ISo 7404-2.ldentification under an immersionmedium of the microlithotypes from their maceral composition.The proportions of the macerals aredetermined using a graticule having a grid with 20 points of intersection spaced to define a distance of50 um on the specimen between extreme intersections in the x (abscissa) and y (ordinate) directions,respectively. The use of such a graticule allows the analyst to comply with the 5 % minimum contentand 50 um minimum size stipulation. 5 Material Immersion medium, having a suitable refractive index and compatible with the microscope objective. NOTE If reflectance measurements are required on the same particulate block, an immersion oil as specified in ISO 7404-5 is used....
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