2811.22 - Silicon dioxide:

This category, HTS code 2811.22, encompasses silicon dioxide in its various forms, excluding carbon dioxide which is classified separately under 2811.21. Silicon dioxide is a fundamental inorganic compound, commonly known as silica, and plays a crucial role in numerous industrial applications. This classification is designed to capture pure or relatively pure forms of silicon dioxide that do not fall under more specific chemical headings within Chapter 28.

Distinguishing this category from its sibling, 2811.21 (Carbon dioxide), is straightforward as carbon dioxide is a gas with distinct chemical properties and uses. This heading specifically targets solid or semi-solid forms of silicon dioxide, ranging from finely powdered forms to more structured materials. It serves as a broad classification for silicon dioxide where further chemical modification or specific preparation methods do not warrant a more detailed subdivision.

Within HTS code 2811.22, further distinctions are made to refine the classification of silicon dioxide. Subcategory 2811.22.10.00 covers "Synthetic silica gel," which is a highly porous, amorphous form of silicon dioxide produced synthetically, often used as a desiccant or adsorbent. The remaining silicon dioxide products not meeting the specific criteria for synthetic silica gel are classified under 2811.22.50.00 as "Other." This bifurcation allows for the separation of a commonly utilized, specifically manufactured form of silicon dioxide from other naturally occurring or less processed varieties.