Inorganic Salts

Sodium Metabisulphite

Chemical formula: Na2S2O5
Content: 97.0% min
SO2: 65.0% min
pH, 10% solution: 4.0 - 4.6

Sodium Metabisulphite is supplied at 97.0% min Na2S2O5 with SO2 at 65.0% min, the two numbers that decide how much active preservative is actually being bought. It works as a preservative, antioxidant and antimicrobial in dried, glazed and candied fruit, in onions and potatoes, in citrus and grape juice and in shrimp and prawn processing, and it is also the standard dechlorination chemical ahead of reverse osmosis membranes. Packing runs from 25 KG bags to 1200 KG jumbo bags at 27 MT per 20ft container.

Why buyers specify this grade

Na2S2O5 content 97.0% min with SO2 65.0% min, so the active sulphite dose is known
Iron 30 ppm max, heavy metals as Pb 5 ppm max and arsenic 1 ppm max
Water insoluble 0.02% max, which matters when it is dosed ahead of RO membranes
pH 4.0-4.6 on a 10% solution for predictable dosing behaviour
25 KG bags up to 1200 KG jumbo bags, 27 MT per 20ft container

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Specification

Na2S2O5 content	97.0% min
SO2	65.0% min
Iron as Fe	30 ppm max
Heavy metal as Pb	5 ppm max
Arsenic as As	1 ppm max
Water insoluble	0.02% max
pH, 10% solution	4.0 - 4.6

Technical data

Chemical formula: Na2S2O5
Content: 97.0% min
SO2: 65.0% min
pH, 10% solution: 4.0 - 4.6
Loading: 27 MT per 20ft container

Quality control

Released on content, SO2, iron, heavy metals, arsenic, water insoluble and pH
TDS and MSDS issued with the order, sample COA on request

Where it is used

Preservative, antioxidant and antimicrobial for dried, glazed and candied fruit
Vegetables including onions and potatoes
Citrus and grape juices
Fish processing including shrimps and prawns
Silage treatment as an antifermentative
Removing excess chlorine in desalting plants with reverse osmosis and in drinking water treatment
Bacteriostatic in starch and sweetener production

Who buys it

Dried fruit and candied fruit processors
Juice producers
Shrimp and seafood processors
Desalination and drinking water treatment operators
Starch and sweetener plants

Problems it solves

Enzymatic browning turning dried fruit and cut potato dark
Residual chlorine destroying reverse osmosis membranes
Black spot in shrimp and prawns during processing and storage
Insoluble residue fouling a dosing line, held to 0.02% max

Packing and options

25 KG polypropylene woven or paper bags with inner PE liner
1000 KG, 1100 KG or 1200 KG jumbo bags
27 MT per 20ft container

How it compares

Sodium bisulphite solutions are easier to dose but cost more to ship because most of the drum is water. Sodium metabisulphite is the dry form with 65% min available SO2, which makes it the economical choice for anything shipped internationally or stored in volume.

Handling and storage

Dissolve shortly before use, sulphite solutions lose strength on standing
When dosing ahead of RO membranes, allow for the 0.02% max water insoluble content
Store dry and sealed, away from acids, in a ventilated place

FAQ

Sodium Metabisulphite questions buyers ask

What content do you supply

Na2S2O5 at 97.0% min with SO2 at 65.0% min.

What packing is available

25 KG polypropylene woven or paper bags with an inner PE liner, and 1000 KG, 1100 KG or 1200 KG jumbo bags, loading 27 MT per 20ft container.

Can it be used for dechlorination

Yes, it is used in desalting plants with reverse osmosis and in drinking water treatment for removing excess chlorine.

What are the heavy metal limits

Heavy metal as Pb 5 ppm max, arsenic 1 ppm max and iron 30 ppm max.

Which foods is it used in

Dried, glazed and candied fruits, vegetables such as onions and potatoes, citrus and grape juices, and fish including shrimps and prawns.

What is the pH in solution

4.0 to 4.6 on a 10% solution.

Download TDS, MSDS and sample COA