Calcium Sulfite Hemihydrate
Calcium sulfite hemihydrate (CaSO3·0.5H2O), a white powder byproduct from flue gas desulfurization, used in construction materials. Falls under HTS 2832.20.00.00 as an 'other sulfite' chemically defined per Chapter 28 Note 1.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If calcium carbonate
Carbonates of inorganic bases like calcium are in 2836, excluded from Chapter 28 sulfites.
If for construction gypsum use
Processed into gypsum plasters shifts to Chapter 25 mineral products.
If as mineral fertilizer additive
Chapter notes exclude fertilizer formulations containing sulfites from Chapter 28.
Not sure which classification is right?
The Tariff Assistant works through the GRI rules on your specific product to reach the right HTS code — and can price the duty on it in the same conversation.
Import Tips & Compliance
• Document hydrate water content; anhydrous form may classify differently if proven
• Comply with CPSC standards if used in building products; labeling required
• Bulk shipments need dust suppression measures; improper handling causes customs holds
Related Products under HTS 2832.20.00.00
Sodium Sulfite Anhydrous
Sodium sulfite (Na2SO3) in anhydrous form is a white crystalline powder used as a reducing agent and preservative. It falls under HTS 2832.20.00.00 as one of the 'other sulfites' excluding sodium and potassium sulfites, which are specified separately in the tariff schedule.
Ammonium Sulfite Solution 40%
A 40% aqueous solution of ammonium sulfite ((NH4)2SO3) used in wastewater treatment and as an oxygen scavenger. Classified under HTS 2832.20.00.00 as an 'other sulfite' of an inorganic base, meeting Chapter 28 definitions for chemically defined compounds.
Zinc Sulfite Powder
Zinc sulfite (ZnSO3) powder used in specialty chemical synthesis and as a corrosion inhibitor. It qualifies under HTS 2832.20.00.00 as a sulfite of an inorganic base (metal salt), distinct from chromates or other excluded compounds.
Magnesium Sulfite Tribasic
Tribasic magnesium sulfite (Mg3(SO3)2) used in pharmaceutical buffering and flame retardants. Classified in HTS 2832.20.00.00 as a chemically defined sulfite salt of an inorganic base.
Ferrous Sulfite Crystals
Ferrous sulfite (FeSO3) crystals employed in analytical chemistry and reducing applications. Meets HTS 2832.20.00.00 criteria as an 'other sulfite' of iron, chemically defined inorganic compound.
Strontium Sulfite Powder
Strontium sulfite (SrSO3) powder for pyrotechnics and specialty ceramics. Under HTS 2832.20.00.00 as a rare earth-adjacent sulfite, excluded from radioactive elements in 2844.