9902.11.61 - Alginic acid (CAS No. 9005-32-7), ammonium alginate (CAS No. 9005-34-9), potassium alginate (CAS No. 9005-36-1), calcium alginate (CAS No. 9005-35-0) and magnesium alginate (CAS No. 37251-44-8) (provided for in subheading 3913.10.00)

This HTS category, 9902.11.61, encompasses specific alginate salts derived from alginic acid. This includes ammonium alginate, potassium alginate, calcium alginate, and magnesium alginate. These substances are chemically modified forms of alginic acid, a natural polysaccharide extracted from brown seaweed. They are primarily used as thickening agents, stabilizers, emulsifiers, and gelling agents in a wide range of industries, including food, pharmaceuticals, and textiles. The presence of the CAS numbers in the description provides a precise method for identifying these specific chemical compounds.

Distinguishing this category from its siblings is straightforward. This node, residing within Chapter 99 of the HTS (Special Classification Provisions), deals with temporary legislation and specific import restrictions, not the fundamental classification of goods by their inherent nature. Its siblings would include other temporary provisions, such as quotas, special duty rates, or specific prohibitions under trade agreements or agricultural adjustment legislation. Therefore, 9902.11.61 is not compared to categories like live animals (0101-0105) based on product type, but rather on the unique temporary regulatory treatment it signifies.

As this is a leaf node, there are no further subcategories to introduce. The classification ends with the specific alginate salts listed. Any further breakdown would occur at a lower level within the primary tariff structure, specifically under subheading 3913.10.00, which provides the primary classification for alginic acid and its derivatives. This chapter 99 provision indicates a special, temporary condition or restriction applied to these otherwise classified goods.