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 dolomi