Abstract

For years, refractory producers have struggled to find an insulative/lightweight (LW) aggregate to use in bricks and monolithics for applications above 2500F (1370°C): petrochemical, power, cement dry calciners, steel ladle covers, preheaters, etc. Imerys is developing a range lightweight aluminosilicate calcines (the initial product is called Mulcoa 43LW), that can be used in light weight formulations capable of reaching 2800F (1540°C) and beyond. Obviously, the main feature of these products is the exceptional refractoriness, associated with a density significantly lower than regular aluminosilicates. But, these materials are also quite interesting in that their open porosity is generally quite low, allowing for casting/gunning/pumping at lower than normal water content than for products based on most other insulative materials. In comparison, this positively affects the dry-out and re-heat shrinkage characteristics, at elevated T, of formulations based on Mulcoa M43LW.

These new LW aggregates allow for the development of a range of finished products: Reduced Cement Insulating Castables, Traditional Insulating Castables and Gunning Castables where, in practice, Mulcoa 43LW acts very similar to normal Mulcoa aggregates.

This study examines the properties of conventional and low cement castable formulations based on Mulcoa M43LW.