Monolithics

Monolithic refractories (single piece cast in the shape of equipment such as one for a ladle shown in Figure 5.7) are replacing the conventional type fired refractories at a much faster rate in many applications including those of industrial furnaces. The main advantages being:

· It eliminates joints which is an inherent weakness

· Method of application is faster and skilled measures in
large number are not required

· Transportation and handling are simple

· Offers better scope to reduce downtime for repairs

· Offers considerable scope to reduce inventory and eliminate special shapes

· It is a heat saver

· Has better spalling resistance

· Has greater volume stability

Various means are employed in the placement of monolithics like ramming, casting, gunniting, spraying, sand slinging, etc. Ramming masses are used mostly in cold applications where proper consolidation of the material is important. The same practice can be adopted with both air setting and heat setting materials. Proper ramming tools need to be selected.

Castables by name implies a material of hydraulic setting in nature. Calcium aluminate cement being the binder, it will have to be stored properly to prevent moisture absorption. Further its strength starts deteriorating after a period of 6 to 12 months.