ISO 21068:2024

Description

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 ISO 21068-2, ISO 21068-3 and ISO 21068-4 are as follows:

–¬†¬†¬†¬† loss on drying (LOD);

–¬†¬†¬†¬† loss on ignition (LOI);

–¬†¬†¬†¬† total carbon, C_total;

–¬†¬†¬†¬† free carbon, C_free;

–¬†¬†¬†¬† silicon carbide, SiC;

–¬†¬†¬†¬† free silicon (Si_free);

–¬†¬†¬†¬† free aluminium (Al_free);

–¬†¬†¬†¬† free magnesium (Mg_free);

–¬†¬†¬†¬† free iron (Fe_free);

–¬†¬†¬†¬† 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).