Super-duty fireclay

The advantage afforded by the 60% alumina brick over the super duty fireclay bricks mentioned above is a higher service temperature limit. The majority of the alumina in a 60% alumina brick is combined with silica to form mullite, and is therefore protected from the alkali/alumina reaction. 

Super-duty Fireclay Refractory. Defined in ASTM - C27 as a fireclay brick having a P.C.E. 33 and an after-contraction 1% when tested at 1600 C. There are three types Regular, Spall Resistant, Slag Resistant. Limits are set for panel spalling loss, modulus of rupture and bulk density. ASTM C-673 specifies a super-duty plastic refractory with P.C.E. 321/. ... 

Modem firebrick (from fireclay, kaolin) and silica brick are available in many compositions and many, many shapes for a wide range of apphcations and to meet varying temperature and usage requirements. High-density, double-burned, and super-duty (low-silica) firebrick have high-temperature heat resistance, but relatively high heat loss thus, they are usually backed by a lower density insulating brick. 

SD = sd = super-duty = the best quality of fireclay brick, secondary air = the second stream of air to be mixed with fuel in, at, or near a burner. See also tertiary air. In an air-atomizing oil burner, the atomizing air might be considered to be primary air and the combustion (or main) air to be secondary air. In an open burner (some air induced by draft), all air through the burner (atomizing and combustion air) may be considered to be primary air, and all through the register to be secondary air. sect = section. 

Industrial applications and uses. As a general rule fireclays are used in both shaped refractories (i.e., bricks) and monolithic refractories (i.e., castables), while super-duty plastic fireclay is used in the preparation of castable recipes. Therefore, the major applications of... 

AI2O3 Phases on phase diagram mullite and glass (can contain free Si02 ) fireclay Highest-quality grades usable to about 1600°C ( super-duty brick) Typically contain 38%-42% AI2O3 and are based on fireclay minerals... 

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