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).