Fireclay brick for blast fur NACE refers to the clay brick used for lining blast furnace. It is required that Fe2O3 content is low, high temperature and normal temperature strength and high density. In the 1950s, China successfully manufactured clay brick for blast furnace and built 1000m3 large blast furnace. Blast furnace clay brick is used for throat, shaft, hearth and bottom of small blast furnace lining. In the 1990s, clay brick was used in the furnace body of large blast furnace, and the rest parts were replaced by high alumina brick, silicon carbide brick and carbon brick. The proportion of clay brick used in blast furnace decreased gradually.
Al2O3 ≥ 42%; Fe2O3 ≤ 1.7%, refractoriness > 1750 ℃, load softening temperature t0.6 (0.2MPa) greater than 1430 ℃, reburning line change (1450 ℃, 3H) 0 ~ - 0.33%, apparent porosity less than 16%, normal temperature lining pressure strength greater than 49MPa.
The clay brick of blast furnace has high compressive strength at room temperature and can resist the wear of furnace charge in regular operation; its volume shrinkage is small under high temperature and long-term operation; it is beneficial to keep the integrity of furnace lining; its apparent porosity is low and Fe2O3 content is low, which reduces the deposition of carbon in the pores and causes the brick to expand loose and damage in the use process; the formation of low melting point is less, which makes the clay brick of blast furnace have better performance than that of common clay brick.
Blast furnace clay brick is used for throat, shaft, hearth and bottom of small blast furnace lining. In the 1990s, clay bricks were used in the body of large blast furnace, and the rest parts were replaced by high alumina bricks, silicon carbide bricks and carbon bricks. The proportion of clay bricks used in blast furnace decreased gradually

Project Indicators	ZGN-42	GN-42
AL2O3,%	≥42	≥42
Fe2O3,%	≤1.6	≤1.7
Fire resistance,℃	≥1750	≥1750
Apparent porosity,%	≤15	≤16
ormal temperature  compressive strengthMPa	≥58.8	≥49.0
0.2MPa load softening  start temperature	≥1450	≥1430
Change rate of reheating line,%	0～-0.2	0～-0.2
Air permeability	This inspection is required. The measured data shall be indicated in the quality certificate.