BS EN ISO 21068-1:2024

This document gives definitions and specifies techniques for the preparation of samples for the chemical analysis of silicon-carbide-containing raw materials and refractory products including: a) SiC raw materials; b) graphite brick containing silicon carbide; c) silicon carbide brick (includes the bricks containing silicon nitride, silicon oxynitride, sialon); d) refractories containing carbon and/or silicon carbide mixed with clay; e) refractories containing carbon and/or silicon carbide mixed with silica (and fused silica); f) refractories containing carbon and/or silicon carbide mixed with high alumina material; g) refractories containing carbon and/or silicon carbide mixed with magnesia (and dolomite); h) refractories containing carbon and/or silicon carbide mixed with chrome mineral or magnesia-chrome materials; i) refractories containing carbon and/or silicon carbide except those described in a) to h) above. The items of analysis described in ISO21068-2, ISO21068-3 and ISO 21068-4 are as follows: — loss on drying (LOD); — loss on ignition (LOI); — total carbon, Ctotal; — free carbon, Cfree; — silicon carbide, SiC; — free silicon (Sifree); — free aluminium (Alfree); — free magnesium (Mgfree); — free iron (Fefree); — silicon(IV) dioxide (SiO2); — aluminium(III) oxide (Al2O3); — iron(III) oxide (Fe2O3); — titanium(IV) oxide (TiO2); — calcium oxide (CaO); — magnesium oxide (MgO); — sodium oxide (Na2O); — potassium oxide (K2O); — chromium(III) oxide (Cr2O3); — zirconium(IV) oxide (ZrO2); — boron oxide (total boron calculated as B2O3); — nitrogen; — oxygen; — nitrides (undifferentiated: Si3N4, AlN, BN, sialon, oxy-nitrides, etc.); — mineralogical phases (XRD-methods).