Sprayable insulating liner compositions for metal vessels

Abstract

Sprayable aqueous insulating liner compositions for metal casting vessels such as permanent refractory lined tundishes are disclosed that contain a water insoluble and hydration resistant particulate refractory grain containing MgO, organic binder and fibers, with the composition being substantially free of water soluble alkali and alkaline earth metal oxides that would migrate during drying with the water to degrade the permanent refractory lining.

What is claimed is: 
     
       1. An insulating liner composition admixed with water and sprayable onto a permanent refractory surface the water being in sufficient amount of said water so that no dust and virtually no rebound of said admixture occurs upon spraying on the inside of a metal carrying vessel to form an expendable liner having low thermal conductivity and high thermal expansion so that the vessel may be easily stripped of said liner after use thereon, comprising a water insoluble and hydration resistant particulate retractory grain, or grain mixture, of at least about 50% by weight of MgO.   .[.an organic.]. .Iadd.a .Iaddend.binder and fibers, said binder in an amount effective to bind said particulate refractory grain and fibers in an essentially dried state on said refractory surface,   said composition being substantially free of water soluble alkali and alkaline earth metal oxides that would migrate during drying with said water to said permanent refractory liner thereby causing degradation or spalling of said permanent refractory.   
     
     
       2. The composition of claim 1 wherein said MgO is supplied by a material selected from the group consisting of magnesite, olivine, magnesite-chrome grain and chrome ore. 
     
     
       3. The composition of claim 1 wherein said organic binder is in an amount of from about 1 to about 10% by weight and said fibers are present in an amount of from about 0.3 to about 5% by weight. 
     
     
       4. The composition of claim 1 wherein said fiber is selected from the group consisting of inorganic fibers and cellulose fibers, and mixtures thereof. 
     
     
       5. The composition of claim 4 wherein said inorganic fibers are in an amount of up to about 2% by weight and said cellulose fibers are in an amount of up to about 3% by weight. .[.6. The composition of claim 1 
     
     
        especially adapted for use as a sprayed tundish liner..]. 7. The composition of claim 1 wherein no more than about 0.10% by weight of said soluble alkali and alkaline earth metal oxides are present in said 
     
     
        composition. 8. The composition of claim 1 containing about 20 to about 
     
     
        30% of water. .Iadd.9.  The composition of claim 1 wherein said binder is an organic binder. .Iaddend. .Iadd.10. The composition of claim 1 wherein said binder is an inorganic binder. .Iaddend. .Iadd.11. The composition of claim 7 wherein said binder is an organic binder. .Iaddend. .Iadd.12. The composition of claim 7 wherein said binder is an inorganic binder. .Iaddend.