Alkali resistant refractories

Abstract

An alkali-resistant refractory material has a surface layer characterized by a greater concentration of lithium than the bulk refractory material.

1 . An article comprising a refractory material having a surface layer characterized by a greater concentration of lithium than said refractory material.  
     
     
         2 . An article in accordance with  claim 1  wherein said surface layer comprises at least one compound selected from the group consisting of lithium aluminate, lithium silicate, and lithium alumina silicate.  
     
     
         3 . An article in accordance with  claim 1  wherein said surface layer is resistant to chemical attack by alkaline species.  
     
     
         4 . An article in accordance with  claim 1  wherein said surface layer protects said refractory from chemical attack by alkaline species.  
     
     
         5 . An article in accordance with  claim 1  wherein said surface layer is adherent to said refractory material.  
     
     
         6 . A method of making an alkali-resistant material comprising the steps of: 
 a. applying to a refractory material at least one lithium-containing material; and    b. heating said refractory material to a sufficient temperature so that said lithium-containing material forms an alkali-resistant surface layer on said refractory material.    
     
     
         7 . A method in accordance with  claim 6  wherein said lithium-containing material is characterized by a melting point of less than 1300° C.  
     
     
         8 . A method in accordance with  claim 6  wherein said lithium-containing material further comprises at least one compound selected from the group consisting of Li 2 CO 3  and LiOH.  
     
     
         9 . A method in accordance with  claim 6  wherein said applying step comprises depositing a layer of said lithium-containing material onto said surface.  
     
     
         10 . A method in accordance with  claim 6  wherein said applying step comprises infusing said lithium-containing material into said surface.  
     
     
         11 . A method in accordance with  claim 6  wherein said heating step is carried out at a temperature in the range of 700° C. to 1300° C.  
     
     
         12 . A method in accordance with  claim 6  further comprising the additional step of: 
 c. exposing said alkali-resistant material to a working material comprising lithium in order to maintain said layer.    
     
     
         13 . A method of forming an alkali-resistant layer on a refractory vessel liner comprising the steps of: 
 a. providing a working material comprising lithium; and    b. heating said working material in said vessel to a sufficient temperature so that said lithium forms an alkali-resistant surface layer on said vessel liner.    
     
     
         14 . A method in accordance with  claim 13  wherein said working material is characterized by a melting point of less than 1300° C.  
     
     
         15 . A method in accordance with  claim 13  wherein said working material further comprises at least one compound selected from the group consisting of Li 2 CO 3  and LiOH.  
     
     
         16 . A method in accordance with  claim 13  wherein said heating step is carried out at a temperature in the range of 700° C. to 1300° C.