Refractory cements and castables are formulated to withstand sustained high temperatures — typically above 1,000°C — and are classified separately from ordinary Portland or hydraulic cements. The key classification criteria include the refractory mineral base (e.g., calcium aluminate, silica, magnesia), the absence of ordinary Portland clinker, and the product's intended use in high-temperature applications. A technical data sheet specifying service temperature and chemical composition supports correct tariff classification.

Yes, pre-mixed and ready-to-use forms are common in trade and generally remain classifiable under this heading regardless of packaging format, provided the composition qualifies as refractory. However, if a product is presented as a kit with non-refractory components or mixed with aggregates that shift its character, reclassification risk increases. Importers should retain the manufacturer's formulation data and intended-use documentation to support the declared classification.