Method for suppressing reaction of molten metals with refractory materials

Abstract

A method is described for improving resistance to chemical attack by aluminum or magnesium in refractory components. In one method, a slurry is formed comprising-calcium silicate-containing refractory material and a barium-containing compound. This slurry is placed in a mould, then dewatered to form a component which is hydrothermally processed to form a final component. In a second procedure, a silica-containing porous refractory component is impregnated with an aqueous solution of an oxide or hydroxide of barium or strontium and thereafter dried in air.

1 . A method of making an unfired refractory component that is resistant to reaction with molten aluminum or magnesium, comprising: 
 (a) forming a slurry comprising calcium silicate-containing refractory material and a barium- or strontium-containing compound;    (b) placing the slurry in a mould;    (c) dewatering the slurry to form the component; and    (d) hydrothermally processing the component to form a final product.    
     
     
         2 . A method according to  claim 1  wherein the barium- or strontium-containing compound is a barium-containing compound selected from barium sulphate, barium oxide and barium hydroxide.  
     
     
         3 . A method according to  claim 2  wherein the barium sulphate is a powder or a slurry.  
     
     
         4 . A method according to  claim 2  wherein the barium oxide or the barium hydroxide is an aqueous solution.  
     
     
         5 . A method according to  claim 4  wherein the aqueous solution is prepared with water at a temperature of at least 30° C.  
     
     
         6 . A method according to  claim 4  wherein the aqueous solution is prepared with water at a temperature of at least 40° C.  
     
     
         7 . A method of stabilizing a silica-containing porous refractory component against reactions with molten aluminum or magnesium, comprising: 
 (a) forming an aqueous solution of an oxide or hydroxide of a group II alkali earth;    (b) impregnating the component with the solution; and    (c) drying the impregnated component in air.    
     
     
         8 . A method according to  claim 7  wherein the group II alkali earth is selected from barium and strontium.  
     
     
         9 . A method according to  claim 7  further comprising impregnating the component with a sulphuric acid solution and drying the component in air, after step (c).  
     
     
         10 . A method according to  claim 7  wherein the porous refractory component is a fired component.  
     
     
         11 . A method according to  claim 7  wherein the porous refractory component is an unfired component.  
     
     
         12 . A method according to  claim 7  wherein the aqueous solution is formed at a temperature of at least 30° C.  
     
     
         13 . A method according to  claim 7  wherein the aqueous solution is formed at a temperature of at least 40° C.