2510 - Natural calcium phosphates, natural aluminum calcium phosphates and phosphatic chalk:

This HTS category, 2510, encompasses natural calcium phosphates, natural aluminum calcium phosphates, and phosphatic chalk. These are mineral substances primarily used as sources of phosphorus and calcium, often in fertilizer production or as animal feed supplements. The classification hinges on the natural origin and specific chemical composition of these phosphates and chalk, distinguishing them from synthetic counterparts or processed materials.

Unlike sibling categories within Chapter 25 which cover a diverse range of minerals such as salt, sulfur, earths, stone, lime, and cement, this node is specifically dedicated to naturally occurring phosphate-rich minerals. It is important to differentiate these from other phosphorus-containing compounds which may be classified elsewhere, depending on their form and intended use.

Within HTS 2510, further subdivisions are made based on the physical state of the material. The subcategory 2510.10.00.00 covers unground forms of these natural phosphates and phosphatic chalk, meaning they are in their raw or minimally processed state. Conversely, 2510.20.00.00 applies to ground or pulverized versions of these same materials, indicating a level of mechanical processing to reduce particle size, typically for improved handling or application in industrial processes.