Sodium Dithionite
Sodium dithionite (Na2S2O4), also known as sodium hydrosulfite, is a white crystalline powder used as a reducing agent in textile bleaching and vat dyeing processes. It falls under HTS 2831.90.00.00 as one of the 'other' dithionites specified in the chapter notes for Chapter 28. This chemically defined inorganic compound is stabilized for industrial use but classified here rather than under organic-stabilized variants.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If stabilized with organic substances like urea or formaldehyde
Chapter note specifies dithionites stabilized with organic substances fall under 2831.10, excluding them from 'other' category.
If imported as part of a formulated bleaching preparation or mixture
Mixtures or preparations containing dithionites are classified in Chapter 38 as chemical preparations, not pure compounds.
If containing significant organic thiocarbonyl components
Organic derivatives of thiocarbonyl compounds fall in Chapter 29, per exclusions from Chapter 28.
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Import Tips & Compliance
• Verify purity and chemical identity via Certificate of Analysis to confirm classification as chemically defined dithionite under Chapter 28 notes
• Ensure proper hazardous material declaration (UN1384) and packaging compliant with DOT/IMDG for reducing agents
• Avoid misclassification as organic derivatives; check for organic stabilizers which shift to specific stabilized subheadings
Related Products under HTS 2831.90.00.00
Zinc Dithionite
Zinc dithionite (ZnS2O4) is an inorganic salt used in industrial reducing applications, particularly in pulp and paper bleaching. Classified under HTS 2831.90.00.00 as 'other' dithionites, it meets Chapter 28 requirements for chemically defined inorganic sulfur-oxygen compounds. Its metal salt nature distinguishes it from organic-stabilized forms.
Potassium Dithionite
Potassium dithionite (K2S2O4) serves as a strong reducing agent in chemical synthesis and wastewater treatment. It is categorized under HTS 2831.90.00.00 for other dithionites, as a chemically defined inorganic compound per Chapter 28 Note 1. Primarily supplied as technical grade powder for industrial applications.
Ammonium Dithionite Solution
Ammonium dithionite (NH4)2S2O4 in aqueous solution acts as a reducing bleach for textiles and paper. Falls under HTS 2831.90.00.00 as 'other' dithionites when chemically defined and not organically stabilized. Concentration typically 20-40% active ingredient for liquid handling.
Sodium Formaldehyde Sulfoxylate
Sodium formaldehyde sulfoxylate (NaHSO2·CH2O) is a sulfoxylate reducing agent used in polymerizations and dye discharge printing. Classified in HTS 2831.90.00.00 as 'other' sulfoxylates when meeting inorganic compound criteria despite formaldehyde association. Technical grade powder or dihydrate form common.