2523.10.00.00 - Cement clinkers

This HTS classification, 2523.10.00.00, specifically covers cement clinkers. Cement clinkers are the primary intermediate product in the manufacture of hydraulic cements, formed by heating a mixture of limestone and clay-rich materials to a high temperature in a kiln, resulting in fused, granular lumps. They are not yet finished cement but are the essential precursor that is subsequently ground with gypsum and other additives to produce the final cement powder.

This category is distinguished from its sibling categories by its stage of production and composition. Portland cement (2523.21.00.00 and 2523.29.00.00) refers to the finished product, finely ground and ready for use, which is produced *from* clinkers. Aluminous cement (2523.30.00.00) is characterized by a high alumina content, giving it different setting and hardening properties and a distinct manufacturing process compared to clinker used for Portland cement. Other hydraulic cements (2523.90.00.00) encompass a broader range of cements not specifically defined as Portland, aluminous, or slag cement.

As cement clinkers represent a leaf node within this chapter, there are no further subcategories under 2523.10.00.00. Classification at this level focuses on the physical form and chemical composition of the fused nodules produced during the calcination of cement raw materials, prior to final grinding and the addition of gypsum. This ensures that the raw material for various types of hydraulic cement is accurately identified and segregated for customs purposes.