Optical Grade Calcium Carbonate
High-purity, low-birefringence calcium carbonate crystals for optical polishing compounds and lens manufacturing aids, under HTS 2836.50.00.00. Synthetic single crystals available.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If fabricated into optical elements
Finished optical components from halides/carbonates classify Chapter 90.
If polishing compound preparation
Formulated polishing slurries become Chapter 38 preparations.
If rare earth doped
Doped optical materials may classify as radioactive/rare earth compounds.
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Import Tips & Compliance
• Provide X-ray diffraction confirming calcite crystal structure
• Test for inclusions (<10 ppm) affecting optical clarity
• Package in inert atmosphere to prevent CO2 absorption/hydration
Related Products under HTS 2836.50.00.00
Precipitated Calcium Carbonate (PCC)
Precipitated calcium carbonate is a fine, white powder produced by chemical precipitation from calcium hydroxide and carbon dioxide, classified under HTS 2836.50.00.00 as chemically defined calcium carbonate. It is widely used as a filler in paper, plastics, and paints to enhance brightness and opacity.
Ground Calcium Carbonate (GCC) Powder
Ground calcium carbonate is a micronized powder derived from high-purity limestone, meeting the definition of calcium carbonate under HTS 2836.50.00.00 when chemically processed. Used in pharmaceuticals, food supplements, and as an antacid.
Nano Calcium Carbonate
Nano-sized calcium carbonate particles (1-100 nm) produced via precipitation for high-performance applications, classified as calcium carbonate under HTS 2836.50.00.00. Used in tire rubber reinforcement, coatings, and advanced composites.
Pharmaceutical Grade Calcium Carbonate USP
USP-grade calcium carbonate meeting pharmacopeia standards for purity and microbial limits, classified under HTS 2836.50.00.00 as chemically defined compound. Primary ingredient in antacids like Tums and calcium supplements.
Food Grade Calcium Carbonate E170
E170 food additive calcium carbonate used as acidity regulator, anticaking agent, and nutrient source, classified under HTS 2836.50.00.00. Meets FCC standards for direct food contact applications.
Calcium Carbonate Filler Masterbatch
Masterbatch containing 70-80% calcium carbonate dispersed in polymer carrier, but classified under HTS 2836.50.00.00 when imported as chemical concentrate. Used for plastics compounding to reduce costs.