This part of ISO 21068 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) graphite brick containing silicon carbide; b) silicon carbide brick (includes the bricks containing silicon nitride); c) refractories containing carbon and/or silicon carbide mixed with clay; d) refractories containing carbon and/or silicon carbide mixed with silica (and fused silica); e) refractories containing carbon and/or silicon carbide mixed with high alumina material; f) refractories containing carbon and/or silicon carbide mixed with magnesia (and dolomite); g) refractories containing carbon and/or silicon carbide mixed with chrome mineral or magnesia-chrome materials; h) refractories containing carbon and/or silicon carbide except those described in a) to g) above.