2521.00.00.00 - Limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement

This HTS classification, 2521.00.00.00, specifically addresses limestone and other calcareous stone that are intended for use in the production of lime or cement. This includes materials primarily composed of calcium carbonate (CaCO3) which undergo calcination or other processes to yield essential industrial products. The key determining factor for classification here is the material's intended industrial application, rather than its finished form or potential for other uses.

In contrast to other mineral products within Chapter 25, such as common salt (Chapter 2501) or sulfur (Chapter 2503), this category is focused solely on raw, calcareous stone for specific manufacturing purposes. It also differs from finished lime or cement products, which would fall under different chapters depending on their specific composition and form. While other types of stone might be found in Chapter 25, the defining characteristic of this entry is its chemical composition and designated use in lime and cement production.

As this is a leaf node within the HTS structure, there are no further subdivisions under 2521.00.00.00. Classification under this heading is based on the physical characteristics of the stone – its calcareous nature – and documentary evidence or clear intent regarding its primary use as a fluxing agent or raw material for the manufacture of lime or cement. Importers should be prepared to provide documentation that substantiates this intended use to customs authorities.