|
Item
|
USP grade
|
Industrial grade
|
|
appearance
|
white tabular crystal
|
white tabular crystal
|
|
purity %
|
≥99%
|
≥98%
|
|
melting point ℃
|
118-120
|
116-120
|
|
sulfide ≤%
|
0.04
|
0.04
|
|
chloride ≤%
|
0.015
|
0.015
|
|
heavy metal ≤ppm
|
10
|
10
|
|
ignition residue ≤%
|
0.01
|
0.01
|