Kaowool and Superwool hardeners are inorganic liquid hardening agents which, when applied to Blanket, Modules or Board, produces a hard surface finish with increased resistance to mechanical abrasion and to gas flow erosion.
Blanket, Modules and Board can be treated to produce depths of hardening varying from a thin eggshell surface to total penetration, the latter resulting in a rigidised material. During storage the Hardener temperature should not fall below +2°C. The product has a shelf life of approximately 12 months.
Hardener is normally used diluted 50-50 with water and can be applied by brushing, spraying, or dipping. Spray operation should be carried out under well ventilated conditions, taking care to avoid breathing in the spray.
The amount needed varies with the type of application, and is dependent on variables such as Blanket density and the depth of treatment required. As a surface coating, 2.5 litres of diluted Hardener will cover 1m2, and 17 litres will saturate the same area of 25mm @ 128kg/m3 Blanket.
Drying procedure is not critical but 12 hours at 90°C is fairly typical. Natural drying is feasible but, in the case of through-hardened Blanket or Board, migration of Hardener to the material surface may occur.
Where enhanced resistance to erosion by high velocity gases is required, such as occur around burner block assemblies, Blanket Modules or Board can be hardened after installation.
A final hardening spray is often given to the Blanket hotface linings of furnaces, ductwork, etc. where gas flow is significant, or when it is desired to impart some resistance to mechanical damage.
Surface hardening is also recommended for applications involving contact with molten non-ferrous metal, e.g. launder linings.