Stabilized refractory compositions

Abstract

A refractory composition including refractory aggregate, one or more matrix components, and silicate-coated set accelerator particles. The silicate-coated set accelerator particles can include one more of silicate-coated calcium hydroxide, magnesium hydroxide, calcium chloride, calcium carbonate, magnesium carbonate and calcium sulfate. Suitable silicate coatings include sodium silicate, potassium silicate, lithium silicate and mixtures thereof. A method of recovering an aged refractory composition, a settable composition and a method of manufacturing silicate-coated calcium hydroxide particles are also provided.

What is claimed is: 
     
         1 . A refractory composition comprising:
 (a) refractory aggregate;   (b) one or more matrix components; and   (c) silicate-coated set accelerator particles.   
     
     
         2 . The refractory composition of  claim 1 , wherein said silicate-coated set accelerator particles comprise silicate-coated particles of one or more of Ca(OH) 2 , magnesium hydroxide, calcium chloride, calcium carbonate, magnesium carbonate, lithium carbonate or calcium sulfate. 
     
     
         3 . (canceled) 
     
     
         4 . The refractory composition of  claim 2 , wherein said silicate coating is chosen from the group consisting of sodium silicate, potassium silicate, lithium silicate and mixtures thereof. 
     
     
         5 . The refractory composition of  claim 2 , wherein said silicate-coated set accelerator particles comprise silicate-coated Ca(OH) 2  particles, wherein said silicate coating is chosen from the group consisting of sodium silicate, potassium silicate, lithium silicate and mixtures thereof. 
     
     
         6 . The refractory composition of  claim 5 , wherein said silicate-coated set accelerator particles comprise sodium silicate-coated Ca(OH) 2  particles. 
     
     
         7 . The refractory composition of  claim 1 , wherein the silicate coating comprises 5% to 70% by weight of the set accelerator particles. 
     
     
         8 - 12 . (canceled) 
     
     
         13 . The refractory composition of  claim 1 , wherein the composition comprises 0.01% to 0.5% by weight of the silicate-coated set accelerator particles. 
     
     
         14 - 18 . (canceled) 
     
     
         19 . The refractory composition of  claim 1 , further comprising a binder. 
     
     
         20 - 24 . (canceled) 
     
     
         25 . The refractory composition of  claim 19 , wherein said binder is chosen from the group consisting of calcium aluminate cement, hydratable alumina, phosphate binder, alkali silicate binder, microsilica gel bond binder, colloidal silica and colloidal alumina. 
     
     
         26 - 37 . (canceled) 
     
     
         38 . The refractory composition of  claim 1 , wherein said silicate-coated set accelerator particles further comprise an anti-caking agent. 
     
     
         39 - 42 . (canceled) 
     
     
         43 . The refractory composition of  claim 1 , wherein said aggregate includes one or more of alumina, bauxite, mullite, bauxitic kaolin, andalusite, calcined kaolin, chamotte, calcined flint clay, pyrophyllite, fused silica, bubble alumina, lightweight clay grog, bubble fly ash, perlite, haydite, vermiculite, fused or sintered magnesia alumina spinels, fused or sintered alumina-zirconia-silica, magnesia, calcium hexaluminate, fused calcium aluminate clinker, sintered calcium aluminate clinker, and lightweight calcium hexaluminate. 
     
     
         44 . (canceled) 
     
     
         45 . The refractory composition of  claim 1 , wherein said matrix components comprise one or more of calcined alumina, reactive alumina, silicon carbide, quartz silica, fume silica, magnesia, kyanite, mullite, spinel (MgAl 2 O 4 ), clay, zircon, graphite, and fly ash. 
     
     
         46 - 47 . (canceled) 
     
     
         48 . A method of recovering an aged, monolithic refractory composition, comprising the steps of adding silicate-coated set accelerator particles to a monolithic refractory composition that has aged at least one month and thereafter mixing the refractory composition with an aqueous liquid and allowing the mixture to set. 
     
     
         49 . The method of  claim 48 , wherein said aged refractory composition comprises refractory aggregate, one or more matrix components and a binder. 
     
     
         50 . The method of  claim 48 , wherein said silicate-coated particles comprise silicate-coated particles of one or more of Ca(OH) 2 , magnesium hydroxide, calcium chloride, calcium carbonate, magnesium carbonate, lithium carbonate or calcium sulfate. 
     
     
         51 - 53 . (canceled) 
     
     
         54 . The method of  claim 48 , wherein said silicate-coated set accelerator particles comprise silicate-coated Ca(OH) 2  particles, wherein said silicate coating is chosen from the group consisting of sodium silicate, potassium silicate, lithium silicate and mixtures thereof. 
     
     
         55 - 67 . (canceled) 
     
     
         68 . The method of  claim 48 , wherein the silicate-coated set accelerator particles are added to the monolithic refractory composition that has aged at least four months. 
     
     
         69 - 70 . (canceled) 
     
     
         71 . The method of  claim 68 , wherein the silicate-coated set accelerator particles are added to the monolithic refractory composition that has aged at least eight months. 
     
     
         72 - 74 . (canceled) 
     
     
         75 . The method of  claim 48 , wherein a binder is included in the refractory composition or is included in the aqueous liquid mixed with the refractory composition. 
     
     
         76 . The method of  claim 75 , wherein said binder is chosen from the group consisting of calcium aluminate cement, hydratable alumina, phosphate binder, alkali silicate binder, microsilica gel bond binder, colloidal silica and colloidal alumina. 
     
     
         77 - 141 . (canceled)