Method for suppressing reaction of molten metals with refractory materials
View Patent ↗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 mold, 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 stabilizing a porous refractory component made of calcium silicate against reactions with molten aluminum or magnesium, the method consisting of:
(a) forming an aqueous solution of an oxide or hydroxide of a group II alkali earth;
(b) impregnating the component made of calcium silicate with the solution; and
(c) drying the impregnated component in air ready for contact with molten aluminum or magnesium.
2. A method according to claim 1 wherein the group II alkali earth is selected from the group consisting of barium and strontium.
3. A method according to claim 2 wherein the porous refractory component is a fired component.
4. A method according to claim 2 wherein the porous refractory component is an unfired component.
5. A method according to claim 2 wherein the aqueous solution is formed at a temperature of at least 30° C.
6. A method according to claim 2 wherein the aqueous solution is formed at a temperature of at least 40° C.
7. A method according to claim 2 wherein the drying of step (c) is carried out at a temperature of no more than 250° C.
8. A method of stabilizing a porous refractory component against reactions with molten aluminum or magnesium, the method comprising:
(a) forming an aqueous solution of an oxide or hydroxide of a group II alkali earth;
(b) impregnating the component made of calcium silicate with the solution;
(c) drying the impregnated component in air; and
(d) further impregnating the impregnated component with a sulfuric acid solution and drying the further impregnated component in air, after step (c), ready for contact with molten aluminum or magnesium.
9. A method according to claim 8 wherein the group II alkali earth is selected from the group consisting of barium and strontium.
10. A method according to claim 9 wherein the porous refractory component is a fired component.
11. A method according to claim 9 wherein the porous refractory component is an unfired component.
12. A method according to claim 9 wherein the aqueous solution is formed at a temperature of at least 30° C.
13. A method according to claim 9 wherein the aqueous solution is formed at a temperature of at least 40° C.
14. A method according to claim 9 wherein the drying of steps (c) and (d) is carried out at a temperature of no more than 250° C.