BS EN ISO 21068-1:2008

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:

1. graphite brick containing silicon carbide;

2. silicon carbide brick (includes the bricks containing silicon nitride);

3. refractories containing carbon and/or silicon carbide mixed with clay;

4. refractories containing carbon and/or silicon carbide mixed with silica (and fused silica);

5. refractories containing carbon and/or silicon carbide mixed with high alumina material;

6. refractories containing carbon and/or silicon carbide mixed with magnesia (and dolomite);

7. refractories containing carbon and/or silicon carbide mixed with chrome mineral or magnesia-chrome materials;

8. refractories containing carbon and/or silicon carbide except those described in a) to g) above.

The items of chemical analysis described in ISO 21068, Parts 1 to 3 are as follows:

1. loss on drying (LOD);

2. loss on ignition (LOI);

3. total carbon, C_total;

4. free carbon, C_free;

5. silicon carbide, SiC;

6. free silicon (Si_free);

7. free aluminium (Al_free);

8. free magnesium (Mg_free);

9. free iron (Fe_free);

10. silicon(IV) oxide (SiO₂);

11. aluminium oxide (Al₂O₃);

12. iron(III) oxide (total iron oxide calculated as Fe₂O₃);

13. titanium(IV) oxide (TiO₂);

14. calcium oxide (CaO);

15. magnesium oxide (MgO);

16. sodium oxide (Na₂O);

17. potassium oxide (K₂O);

18. chromium(III) oxide (Cr₂O₃);

19. zirconium oxide (ZrO₂);

20. boron oxide (total boron calculated as B₂O₃);

21. nitrogen;

22. oxygen;

23. nitrides (undifferentiated: Si₃N₄, AlN, BN, sialon, oxy-nitrides, etc.).

The range of determination specified in this part of ISO 21068 is given in Table 1.

Table 1

Range of determination

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