Low Cement Castable

 Low Cement Castable Introduction

Low cement castable, is calcium aluminate cement bonded castable, but its calcium aluminate cement content is below 2.5%, only half or one third that of ordinary calcium aluminate cement bonded castable, that’s why it is called low cement castable.  According to American ASTM standards, CaO content between 1.0%~2.5% is called low cement castable, CaO content less than 1.0% is called ultra low cement castable. Low cement refractory castalbe adopts superfine power(less than 10μm) as coagulating agent, so  low cement castable is hydration binding and coagulation binding coexisted castable. Low cement high alumina castable is widely used in thermal equipments, heating furnace in metallurgical industry, boilers in power industry and building material industrial furnace.

Low Cement Castable Classifications
 

According to raw refractory material types, low cement castable is divided into low cement clay castable, low cement high alumina castable, low cement mullite castable, low cement corundum castable, low cement chrome corundum castable, low cement zircon mullite castable, low cement zircon mullite castable, low cement alumina sipnel castable, low cement carbon and silicon carbide castable, etc. By workability, low cement castable and ultra low cement castable are divided into vibration low cement castable, ultra low cement castable, self flow low cement and ultra low cement castable.

Low Cement Castable Properties

1. Low CaO content, the amount of eutectic mixture is reduced, therefore, low cement  castable has higher refractoriness, better high temperature strength and slag corrosion resistance.

2. Compared with ordinary castable, low cement castable only needs one third of water, so the casted body has lower porosity and higher bulk density.

3. When casted into shapes, there is few cement hydrates and will not have hydration bond disintegration during heating, so the middle temperature strength will not decrease, and its mechanical strength gradually increases with the rising of heat treatment temperature.

4. When the granularity composition is properly adjusted, it can be used to prepare self flow castable and pump grouting castable.


Low Cement Castable Physical & Chemical Index

Item	Clay	High alumina	Corundum
Al2O3 %	45	75	92
SiO2 %	50	12	5
CaO %	<1.8	<1.5	<1.5
Bulk Density(110℃, 24h) g/cm3	2.3	2.6	3.0
Cold crushing strength(110℃, 24h) Mpa	72	75	85
Linear change rate(1350℃, 3h) %	±0.3	±0.5	±0.5
Max working temperature ℃	1450	1600	1700
Water needed %	6.0~6.5	6.0~6.5	4~5

 
 
Low Cement Castable and Ultra Low Cement Castable Applications

Low cement castable is widely used in various kinds of industrial furnaces and kilns, covering metallurgy, petrochemical industry, machinery manufacturing, power plant, building material and so on. Low cement castable has replaced traditional refractory products to build linings. Vibration type low cement and is mainly used to make thick linings, such as the inner lining of heating furnaces, heat treatment furnaces, electric furnace cover, vertical kilns, rotary kilns, blast furnaces tapping spout, steel ladle, iron ladle, etc. Self flow low cement castable is mainly used as thin linings and high temperature refractory components linings with metal anchoring parts. For example, water cooling pipe outer lining of heating furnaces, linings of integral gunning machine used for gunning metallurgy, RH and DH vacuum degassing equipment impregnation pipe lining, ladle gas supplying elements( permeable bricks) and high temperature abrasion resistant linings of petrochemical industry catalytic cracking reactors.