Castable Refractory Mixes

Castable refractory mixes, also known as refractory concretes, are applied in place by casting, just like their name. They are a mixture of various components like alumina cements, fillers, very fine-sized materials and additives and form a hydraulic or chemical bond. For these mixes, calcium aluminate cements are their main and common binders. It’s mentionable that steels and cast irons industry play the main role in the development and evolution of such mixes. Castable refractories are classified into five main categories:

Conventional or regular cement castables (RCC)

Medium cement castables (MCC)

Low cement castables (LCC)

Ultra-low cement castables (ULCC)

Non-cement castables (NCC)

Conventional or Regular Cement Castables (RCC)

For these mixes, some of their significant features are: quicker installation method, no need for using molds or any complicated stamping and improved possibility of troweling and patching erosion cuts. Required water amount for RCCs to make them ready, is determined according to the “ball in hand” test instructions (ASTM C860).These mixes are usable in various industries and conditions, such as steel, ceramics, glass, alumina, rolling mills furnaces, petrochemistry and cement industries.

Medium Cement Castables (RCC)

These mixes will be having a lower porosity after sintering; thus they have more corrosion resistance rather than RCCs. In comparison to RCCs, these mixes have lower cement amount and by developing them, their cement amount is being reduced step by step. If MMCs are heated quickly, spalling happens to them due to quick vaporization of water, existing in the cement structure. This is one of their main disadvantages. Therefore water vaporization should occur in a certain temperature range.Low, Ultra-low and Non-cement Castables (LCC, ULCC and NCC) It’s obvious that these mixes’ main feature is their lower need for water addition, which results in a higher density and less porosity. Unlike conventional castables, which lose their strength in a medium temperature range due to cement dehydration, LCCs, ULCCs and NCCs’ strength grows as the temperature raises. Of their common applications, just like RCCs, utilization in steel (induction furnaces’ roof and skewback ring and rolling mills furnaces), ceramics, glass, alumina, petrochemistry and cement industries can be named. Behin Nasooz Co. castable mixes are presented as the following grades: