7202.21.90.00 - Containing by weight more than 90 percent of silicon

This HTS category, 7202.21.90.00, specifically classifies ferrosilicon alloys that contain a very high concentration of silicon by weight, exceeding 90 percent. Ferrosilicon, in general, is an alloy of iron and silicon used primarily as a deoxidizer and alloying element in the production of steel and cast iron. This particular subcategory targets the purest forms of ferrosilicon, where silicon is the dominant component by weight.

Distinguishing this category from its siblings, the key differentiator is the precise silicon content. While other ferrosilicon categories at this level cover alloys with more than 55% silicon but not exceeding 90% silicon, this classification is reserved for those that surpass the 90% threshold. This strict numerical cutoff based on silicon's weight percentage is critical for accurate customs declaration and duty assessment.

As this node represents a leaf in the HTS classification tree, there are no further subcategories. Therefore, the focus for classification within 7202.21.90.00 is solely on confirming that the ferrosilicon product's silicon content, by weight, is definitively greater than 90 percent. This precise measurement is the sole criterion for placing an import or export under this specific HTS code.