Fire Clay and High Alumina Refractory Bricks for Furnaces and Kilns

Fire clay and high alumina refractory bricks line the hot faces of high-temperature furnaces and kilns. They build and repair the walls, roofs, hearths and flues of glass furnaces, blast furnaces, hot-blast stoves, cement and lime kilns, boilers, ladles and fireplaces, where they keep their shape and strength at temperatures that would melt or deform an ordinary brick. Made from alumina-silica raw materials and fired hard, they resist heat, thermal cycling and the load of the structure above them.

It is the alumina content. Fire clay bricks are the lower-alumina grades, roughly 30 to 45 percent alumina, and serve as the economical general-purpose refractory for moderate temperatures. High alumina bricks carry more alumina, from about 48 percent up to 80-plus, which lifts their refractoriness, their strength at temperature and their resistance to slag and chemical attack. The hotter and more demanding the service, the higher the alumina grade chosen.

SK is a refractoriness rating — the higher the SK number, the higher the temperature the brick withstands before it softens. The grades run from SK-30, a fire clay brick, up to SK-40, a high alumina brick, and each step up brings a higher alumina content, a higher refractoriness under load and a higher crushing strength. The SK number is a quick way to match a brick to how hot and how loaded its position in the furnace is.

By the temperature, the load and the chemistry at that spot in the furnace. A cooler, lightly loaded area can use a fire clay grade, while the hottest, most loaded or most chemically attacked zones need a high alumina grade with a higher refractoriness under load. Slag, glass melt and abrasion all push the choice further up the range. Tell us the furnace, the working temperature and the zone, and we will recommend the grade and the shape.

We supply a standard 230 by 114 by 65 millimetre brick and the full range of standard refractory shapes, and we make custom and special shapes to your drawing. Straights, wedges, arches, keys and cast shapes are all available to build walls, arches and hearths. Send us the furnace drawing or the shapes you need, and we will quote the grade, the shapes and the quantities.