ISO 21068-1:2024

Chemical analysis of raw materials and refractory products containing silicon-carbide, silicon-nitride, silicon-oxynitride and sialon — Part 1: General information, terminology and sample preparation

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).

Edition	2024
Standard Part No	1
Published Date	2024
Published By	International Standardization Organisation
Page Count	6