Sodium Metabisulfite
Sodium Metabisulfite
Product Name: Sodium Metabisulfite
Alias: Sodium Pyrosulfite
Category: Inorganic chemical/inorganic salt
CAS NO: 7681-57-4
EC NO:231-673-0
Molecular Formula: Na2S2O5
Molecular Weight: 190.1
Properties: white or yellowish crystalline powder with strong SO2 odor; specific wt.: 1.4. Soluble in water, its aqueous solution is acidic.
Appearance: White Free Flowing Fine Crystal or Powder
Specification For Food Grade and Industry Grade :
Item Quality spec.
Food Grade Technical Grade
Purity (Na2S2O5) ≥98.0% ≥97.0%
Sulfur dioxide( SO2) ≥65.0% 65.0%
Arsenic ( As ) ≤0.0002% -
Heavy metal (Pb) ≤0.0005% -
Selenium (Se ) ≤0.0005% -
Iron (Fe) ≤0.001% ≤0.002%
Insol. in water ≤0.02% ≤0.05%
pH-value : 4.0-4.8 4.0-4.8
Note: Meet FCC V and E 223 standard
Specification for Pharmaceutical Grade and Photo Grade  
Item Quality Index
Pharmaceutical Grade Photo Grade
Purity ( As Na2S2O5) 98.0% min 98.0% min
Sulfur Dioxide( SO2) 65.0% min 65.0% min
Thiosulphate ( As S2O3) : 0.05 % max 0.05% max
Chloride ( As CL-) : 30 ppm max 50ppm max
Arsenic ( As ) : 1ppm max 1ppm max
Lead ( Pb ) : 1 ppm max 2ppm max
Copper (Cu) : 1 ppm max 1ppm max
Iron (Fe ) : 5 ppm max 5ppm max
Mercury (Hg) : 0.1ppm max 1ppm max
Chromium (Cr) : 1 ppm max -
Selenium (Se ) : 1 ppm max 5ppm max
Zinc (Zn) 1 ppm max 1ppm max
Cadmium (Cd ) 1ppm max -
Nickel (Ni) 1ppm max -
Na2SO3 + Na2SO4 1.5% max -
PH value : 4.0-4.8 4.0-4.8
Remark : Conformed with USP standard
Packing:25kg plastic woven bag, 25kg Kraft paper bag, 25kg PE bag, 500kg/1000kg/1100kg/1200kg jumbo bag or as per the buyer's requirement.
(1) Food Grade: Bleach agent (e.g. candies, cake, bamboo shoots, etc); Loose agent (e.g. bread, cracker etc); Antiseptic and germicide (e.g. fruit juice, tinned food, brews, the cereals food is defended storage etc); Inhibitor and freshen agent (e.g. day lily, seafood, fruit and vegetable etc).
(2) Industry Grade: Mordant of printing and dyeing; Dechlorinate of textile after bleaching; Sulphonated agent and reducer of chemical industry and pharmacy; Bleach of paper pulp, bamboo and timber bleach of Stap; Treatment agent of waste water; Rubber solidifying agent Perfume industry is served as hydro carbon perfume aldehyde
The hide profession employ to do to molt dose and pliable dose and wearproof dose; sewage treatment, and so on .
(3) Pharmaceutical Grade: In chemical synthesis in the production of acrylic fibre, vitamin K, vitamin A, pharmaceutical intermediates, etc.
(4) Photo Grade: The sensitize industry is served as the developing agent reductant and the protection of fixing bath dose.
Storage: Store the product in a dry and cool place.