BS ISO 7404-4:2017

This standard BS ISO 7404-4:2017 Methods for the petrographic analysis of coals is classified in these ICS categories:

• 73.040 Coals
• 75.160.10 Solid fuels

This document specifies a method, using a graticule with 20 crossline intersections, for determining the proportions of microlithotypes, carbominerite and minerite in coals. It applies only to determinations made on polished particulate blocks using reflected white light (about 400 nm to 700 nm). Additional blue, blue-violet or UV light excitation (365 nm to 440 nm) for better identification of liptinite in fluorescence may be used especially at low rank coals.