Žáruvzdorné materiály s nízkým a ultra nízkým obsahem cementu

Low and ultra-low Cement Castables have small pore size, large density, good volume stability, high strength, and a small amount of water. They overcome the characteristics that the strength of ordinary castables decreases significantly at 800~1200 ℃, increases with the increase of temperature, and have excellent thermal shock resistance, slag resistance, and corrosion resistance.

Technical parameters of low and ultra-low cement castables

Položka		Index
Položka		Clay	High Alumina	Corundum
Al₂O₃ %		≥45	≥75	≥98
Cao %		＜1.8	＜1.5	＜1.0
Bulk density g/cm³	110℃×24h	≥2.3	≥2.6	≥3.1
	1350℃ × 3 h	≥2.26	≥2.61	/
	1550℃ × 3 h	/	/	≥3.00
Cold Crushing Strength MPa	110℃×24h	≥70	≥75	≥85
	1350℃ × 3 h	≥85	≥90	/
	1550℃ × 3 h	/	/	≥100
Flexural Strength MPa	110℃×24h	≥6	≥8	≥9
	1350℃ × 3 h	≥8	≥9	/
	1550℃ × 3 h	/	/	≥11
Permanent linear change Rate %	1000℃ × 3 h	-0.3	-0.2	-0.2
	1350℃ × 3 h	±0.3	±0,5	/
	1550℃ × 3 h	/	/	±0,5
Maximum service temperature ℃		1450	1600	1800

Classification of low cement castables

Low cement castables are classified into aluminum silicate, mullite, korund, magnesia aluminum, quartz, carbon, and silicon carbide. Different materials of low cement castables have different uses. Silicon carbide low cement castables are divided into furnace-tapping trough castables and steelmaking ladle castables.

Application of low and ultra-low cement castables

Clay and high-alumina low-cement castables are mostly used in heating furnaces and soaking furnaces, and are also used in some parts of the lining of heat treatment furnaces and rotary kilns for building materials; low-cement castables can also be used in high-temperature burner linings, heating furnace water-cooling pipe wrapping linings; blast furnace iron troughs, cupola iron troughs, molten iron pretreatment integral powder spraying guns and other linings, atd. Corundum and chromium-containing corundum low-cement castables are used for linings of certain parts of steel refining devices outside the furnace, and are also used for industrial frequency induction furnace linings, high-temperature wear-resistant linings of petrochemical catalytic cracking reactors, atd.;