2519.90 - Other:

HTS code 2519.90, categorized under "Other," encompasses magnesium oxide and carbonate products that do not fall under the more specific sibling category of natural magnesium carbonate (magnesite), HTS code 2519.10. This broad designation includes a range of manufactured or processed magnesium compounds.

Distinguishing this category from its sibling, 2519.10, is crucial. While 2519.10 specifically covers naturally occurring magnesium carbonate (magnesite) in its raw or minimally processed form, 2519.90 is reserved for magnesium oxides, including fused magnesia, dead-burned (sintered) magnesia, and other magnesium oxides, which have undergone significant processing such as calcination or sintering.

Within HTS code 2519.90, further distinctions are made through subcategories. HTS 2519.90.10.00 specifically addresses fused magnesia and dead-burned (sintered) magnesia, products characterized by their high density and refractory properties achieved through high-temperature processing. HTS 2519.90.20.00 covers caustic calcined magnesite, which is produced by heating magnesite at lower temperatures and retains a higher reactivity. Finally, HTS 2519.90.50.00 serves as a residual category for any other magnesium oxide or carbonate products that do not fit the more specific subheadings.