2523.30.00.00 - Aluminous cement

This HTS category, 2523.30.00.00, specifically classifies aluminous cement. Aluminous cement, also known as high-alumina cement (HAC), is a hydraulic cement that derives its binding properties primarily from calcium aluminates. It is characterized by its rapid setting and hardening times, and its high strength development, particularly at elevated temperatures and in environments aggressive to Portland cement. Its production involves fusing or sintering bauxite or other aluminum-rich materials with limestone.

Aluminous cement is distinguished from its siblings by its distinct chemical composition and performance characteristics. While Portland cement (covered under 2523.20) is based on calcium silicates, and slag cement (part of 2523.90) utilizes blast furnace slag, aluminous cement's primary constituents are calcium aluminates. Cement clinkers (2523.10.00.00) are the intermediate product before grinding into cement, whereas this classification covers the finished cement product.

As this is a leaf node within the HTS structure, there are no further subcategories. Therefore, classification under 2523.30.00.00 hinges on confirming the material's composition as primarily calcium aluminates, distinguishing it from other hydraulic cements based on their dominant mineralogical composition and intended applications, such as high-temperature refractories or specialized concrete formulations where rapid strength gain and chemical resistance are paramount.