2519.90.10.00 - Fused magnesia and dead-burned (sintered) magnesia

This HTS category, 2519.90.10.00, specifically covers fused magnesia and dead-burned (sintered) magnesia. Fused magnesia is produced by melting natural magnesite or magnesium oxide at extremely high temperatures, resulting in a dense, crystalline material. Dead-burned magnesia, also known as sintered magnesia, is produced by heating magnesium oxide to a point where it loses its reactivity and becomes suitable for refractory applications. These products are characterized by their high melting point and excellent resistance to heat and chemical attack. Small quantities of other oxides may be present, as long as they were added before the sintering process.

It is important to distinguish this category from its sibling, 2519.90.20.00, which covers caustic calcined magnesite. Caustic calcined magnesite is produced at lower temperatures and retains its reactivity, making it suitable for agricultural and chemical applications, unlike the inert nature of fused and dead-burned magnesia. The other sibling category, 2519.90.50.00, acts as a residual category for any other magnesium oxide products not specifically classified elsewhere within heading 2519.

As a leaf node, 2519.90.10.00 does not have further subcategories. Therefore, classification within this code hinges on the accurate identification of the product as either fused magnesia or dead-burned (sintered) magnesia, distinguishing it from the more reactive forms of magnesium oxide covered by other HTS classifications within heading 2519.