Technical indexes

High pure

Industrial grade

Photographic grade

sodium sulfite

Top grade

First grade

sodium sulfite

Na2SO3 ≥ %

98.0

97.0

96.0

97.0

Fe ≤ %

0.003

0.003

0.005

0.002

Water-insoluble matter ≤ %

0.01

0.02

0.03

0.05

Free alkali (Na2CO3 ) ≤ %

0.001

0.1

0.4

0.15

Sodium sulfate (Na2SO3) ≤ %

1.2

2.5

-

-

Sodium chloride (NaCl) ≤ %

0.003

0.1

-

-

Heavy metals (as Pb) ≤ %

0.001

-

-

0.002

Arsenic (As) ≤ %

0.0001

-

-

-

Sodium thiosulfate ≤%

0.001

-

-

0.0015

Appearance of Aq. solution

Qualified

-

-

Qualified

Reaction of Silver nitrate ammonia solution

Qualified

-

-

Qualified