Grade
Index name

Prime

First

Second

Third

P -1

P -2

I -1

I -2

II -1

II -2

III -1

III -2

Boron trioxide ( B₂O₃) ≥

24

22

20

18

16

14

12

10

Total iron(Fe₂O₃) ≤

15

Calcium oxide t(CaO ) ≤

8

Magnesia ( MaO) ≤

45

Ore lumpiness<

400( ≤15% within 300-400mm,<15% within 20mm)