9902.01.31 - Amorphous silicon dioxide micro-spheres of mean particle size 0.003-0.018 mm, linseed oil absorption 30-40 ml/g, surface area less than 80 m²/g, and pore volume less than 0.1 ml/g (CAS No. 7631-86-9) (provided for in subheading 2811.22.10)

This HTS classification, 9902.01.31, specifically covers amorphous silicon dioxide micro-spheres meeting a precise set of physical and chemical criteria. These characteristics include a mean particle size ranging from 0.003 to 0.018 mm, a linseed oil absorption capacity between 30 and 40 ml/g, a surface area less than 80 m²/g, and a pore volume below 0.1 ml/g. The CAS number 7631-86-9 is also provided for definitive identification. It is crucial to note that this special classification is provided for under subheading 2811.22.10, indicating its primary material composition.

The purpose of this specific subheading within Chapter 99 of the HTS is to address goods subject to temporary legislation, modifications related to trade agreements, or additional import restrictions proclaimed under Section 22 of the Agricultural Adjustment Act. While other categories within Section XXII might cover goods under specific trade provisions, this node is distinguished by its focus on a highly specialized form of amorphous silicon dioxide with unique physical properties, not by its general material type.

As this is a leaf node within the HTS database, there are no further subcategories. Classification decisions for this item will hinge on a thorough verification of the stated physical and chemical specifications. Importers and exporters must ensure that the imported or exported amorphous silicon dioxide micro-spheres precisely match the parameters outlined in the description to qualify for this specific tariff classification.