ULTRA LOW CEMENT CASTABLES (ULCC)

A ULCC contains less than 3% calcium aluminate cement, with the rest of the matrix bonded by reactive alumina, microsilica and chemical dispersants. The result is a very dense, low-porosity (8–14%) castable with hot strength approaching that of bricks, excellent slag resistance and very low permeability. ULCC is used in the most-aggressive wear zones of steel and aluminium plants.

Specify ULCC where lining life is the dominant cost driver, steel ladle slag bands, EAF tap holes, reheating furnace skid rails, copper anode furnace launders, aluminium melter ramps, and continuous casting tundish working linings. ULCC typically gives 1.4–2× the life of LCC in these zones, justifying the 30–80% price premium.

Stricter. ULCC has even lower permeability than LCC, so trapped moisture is harder to vent. Dry-out is typically 48–96 hours: ambient to 110°C at 8°C/hr, hold 18 hours, then 20°C/hr to 350°C, hold 12 hours, then 35°C/hr to working temperature. Many ULCC mixes include organic fibres that burn out at 200–300°C to create venting channels.

Up to 1700–1800°C depending on aggregate. Standard 80–90% Al₂O₃ ULCC handles 1700°C. Tabular alumina or fused alumina-spinel ULCC reaches 1800°C continuous. For higher service temperatures (1850°C+), no-cement (chemically bonded) castables or shaped refractories should be used.

Yes, premium ladle linings increasingly use 90% Al₂O₃ ULCC with 6–10% spinel addition. Typical campaign life is 110–180 heats versus 80–140 for standard LCC. The cost premium is offset by reduced relining frequency and lower lost-production hours. Slag bands and impact zones may still be supplemented with MgO-C bricks.

CUMI Super Refractories ULCC range, we are the authorised dealer. Also Calderys ACCMON, ULTRACASTING and KERAFLEX series, and IFGL ULCC for steel applications. Each manufacturer has 4–6 grades; we help you select the right grade based on your installation method, vessel size, slag chemistry and target campaign life.