Large refractory article and method for making

Abstract

A method of sintering large refractory ceramic articles is disclosed. The method includes supporting a green refractory body on a plurality of support plates, the support plates in turn being supported by a plurality of support members having arcuate upper and lower surfaces. A setter material is disposed between the green refractory body to be sintered and the support plates. As the refractory body is sintered, the density of the article increases. Concurrently, the dimensions of the body decrease, which shrinkage, unless otherwise accommodated, may cause fracture of the body. The support plates and the structure of the support members, move to prevent the development of detrimental stresses in the refractory body as it sinters.

1 . An isostatically pressed and sintered monolithic refractory article comprising:
 a mass greater than 450 kg;   a porosity less than 20%; and   a length greater than 250 cm.   
     
     
         2 . The refractory article according to  claim 1 , wherein the porosity is less than 10%. 
     
     
         3 . The refractory article according to  claim 1 , wherein the mass is greater than 1000 kg. 
     
     
         4 . The refractory article according to any of  claims 1 , wherein the refractory article comprises a trough, and forming surfaces that converge at a root. 
     
     
         5 . The refractory article according to  claim 1 , wherein the refractory article comprises zircon or xenotime. 
     
     
         6 . A method of making a glass sheet comprising:
 heating a batch material in a furnace to produce a molten glass;   flowing the molten glass over converging forming surfaces of a refractory body to form the glass sheet; and   wherein the refractory body has a mass greater than 450 kg and a length greater than 250 cm.   
     
     
         7 . The method according to  claim 6 , wherein the mass of the refractory body is greater than 1000 kg. 
     
     
         8 . The method according to  claim 6 , wherein the refractory body comprises zircon or xenotime. 
     
     
         9 . A method of forming a sintered refractory article, comprising:
 positioning a green refractory body on a plurality of support plates separated by gaps, wherein the support plates are supported by a plurality of support members, each of the support members having an arcuate upper surface of constant radius of curvature and an arcuate lower surface of constant radius of curvature, and the radius of curvature of the arcuate upper surface is equal to the radius of curvature of the arcuate lower surface, there being a layer of setter material disposed between the green refractory body and the support plates;   heating the green refractory body to form a sintered refractory article; and   wherein during the heating the green refractory body contracts, causing the support plates to translate in response to the contraction of the green refractory body and the support members to rotate in response to the translation of the support plates.   
     
     
         10 . The method according to  claim 9 , wherein a longest dimension of the sintered refractory article is at least about 250 cm. 
     
     
         11 . The method according to  claim 9  wherein a mass of the sintered refractory article is at least about 450 kg. 
     
     
         12 . The method according to  claim 9 , wherein a mass of the sintered refractory article is greater than 1000 kg 
     
     
         13 . The method according to  claim 9 , wherein the green refractory body was formed by isostatically pressing a refractory material. 
     
     
         14 . The method according to  claim 9 , wherein a radius of curvature of the upper and lower arcuate surfaces is at least 30 cm. 
     
     
         15 . The method according to any of  claims 9 , wherein a joint material is disposed in the gaps between adjacent support plates. 
     
     
         16 . The method according to  claim 9 , wherein a center of gravity of the support members is displaced from a center of rotation of the support members. 
     
     
         17 . The method according to  claim 9 , wherein the sintered refractory article is an isopipe. 
     
     
         18 . The method according to  claim 9  wherein the sintered refractory article comprises zircon or xenotime. 
     
     
         19 . A method of forming a sintered refractory article, comprising:
 positioning a green refractory body having a mass of at least 450 kg on a plurality of support plates in a furnace, wherein the support plates are supported by a plurality of support members and adjacent support plates are separated by gaps, each of the support members being a portion of a cylinder;   heating the green refractory body in the furnace to form a sintered refractory article; and   wherein the green refractory body contracts during the heating, causing the support plates to translate in response to the contraction of the green refractory body and the support members to rotate in response to the translation of the support plates.   
     
     
         20 . The method according to  claim 19 , wherein the mass is greater than 1000 kg.