Item

Index

Prime

First

Qualified

Magnesium sulfate( MgSO₄.7H₂O) Main content ≥

96.0

95.0

90.5

Boric acid ( H₃BO₃)content  ≥

3.7

3.6

3.0

water-fast substances ≤

0.010

0.040

0.060

Oxide( CI) ≤

0.050

0.10

0.15

Ferrum ( Fe) ≤

0.0020

0.0030

0.0050