Assay

pH of a 5% Solution @ 25 C

Ca and Mg precipitate

Insoluble matter

Iron (Fe)

Heavy Metals (as Pb)

Residue after ignition

Phosphate (PO4)

Sulfate (SO4)

Notes:

99.5% min.

4.5 - 5.5

0.002% max.

0.005% max.

2 ppm max.

5 ppm max.

0.01% max.

2 ppm max.

0.002% max.