2836.50.00.00 - Calcium carbonate

This category specifically classifies calcium carbonate. Calcium carbonate is a chemical compound with the formula CaCO3, commonly found in nature as the minerals calcite and aragonite. It is a widely used industrial mineral and chemical feedstock, appearing in various forms such as powdered, crystalline, or precipitated. Its applications span diverse industries including construction (as cement and aggregate), agriculture (as a soil conditioner), food (as a dietary supplement and anticaking agent), pharmaceuticals (as an antacid and calcium supplement), and manufacturing (as a filler in plastics, paper, and paints).

Distinguishing calcium carbonate from its sibling categories is crucial for accurate classification. While all fall under the broader heading of carbonates, this code exclusively pertains to the calcium compound. For instance, disodium carbonate (2836.20.00.00) and sodium hydrogencarbonate (2836.30.00.00) are distinct salts of carbonic acid involving sodium. Similarly, potassium carbonates (2836.40) and barium carbonate (2836.60.00.00) represent compounds of different alkali and alkaline earth metals. This classification hinges on the specific metallic cation bonded to the carbonate anion.

As this HTS classification for calcium carbonate is a leaf node, there are no further subdivisions within this specific code. Classification at this level is determined by the chemical identity of the substance itself. Therefore, any product primarily consisting of calcium carbonate, regardless of its physical form (e.g., chalk, limestone powder, precipitated calcium carbonate), will fall under this heading, provided it meets the chemical definition of calcium carbonate and is not classifiable under a more specific heading elsewhere in the tariff schedule based on its intended use or further processing.