Alumina honeycomb structure, method for manufacture of the same, and heat-storing honeycomb structure using the same

Abstract

In an alumina honeycomb structural body according to a first aspect of the invention and another invention relating it, the alumina honeycomb structural body is constructed in such a manner that alumina is a main ingredient and an amount of impurities is limited to not greater than 2 weight %. Moreover, in an alumina honeycomb structural body according to a second aspect of the invention and another invention relating it, the alumina honeycomb structural body is constructed in such a manner that an amount of alumina as a main ingredient is limited to not less than 98 weight %; an amount of Na containing compound is limited to 0.02 weight %-1.0 weight % of Na 2 O when converting it into oxide; and remainder is impurities.

1 . An alumina honeycomb structural body, comprising: alumina as a main ingredient and not greater than 2 weight % of impurities.  
     
     
         2 . The alumina honeycomb structural body according to  claim 1 , wherein a porosity is not greater than 50%, preferably not greater than 15%, a thermal expansion coefficient is not greater than 8.5×10 −6 /° C., and a main crystal phase is α alumina.  
     
     
         3 . The alumina honeycomb structural body according to  claim 1 , wherein an amount of impurities is not greater than 1 weight %.  
     
     
         4 . A method of manufacturing an alumina honeycomb structural body, comprising the step of: mixing 97 weight %-70 weight % of α alumina, 3 weight %-30 weight % of aluminum hydroxide, forming agents, and solvents to obtain a plastic substance; extruding the plastic substance to obtain an extruded honeycomb body; and firing the extruded honeycomb body to obtain an alumina honeycomb structural body having α alumina as a main crystal phase.  
     
     
         5 . An alumina honeycomb structural body, comprising: not less than 98 weight % of alumina as a main ingredient; a Na containing compound having 0.02 weight %-1.0 weight % of Na 2 O when converting it into oxide; and remainder of impurities.  
     
     
         6 . The alumina honeycomb structural body according to  claim 5 , wherein a porosity is not greater than 50%, preferably not greater than 15%, a thermal expansion coefficient is not greater than 8.5×10 −6 /° C., and a main crystal phase is α alumina.  
     
     
         7 . A method of manufacturing an alumina honeycomb structural body containing Na, comprising the steps of: mixing 97 weight %-70 weight % of α alumina, 3 weight %-30 weight % of aluminum hydroxide, necessary amount of sodium source, forming agents, and solvents to obtain a plastic substance; extruding the plastic substance to obtain an extruded honeycomb body; and firing the extruded honeycomb body to obtain an alumina honeycomb structural body having α alumina as a main crystal phase.  
     
     
         8 . A honeycomb regenerator, comprising: at least one alumina honeycomb structural body set forth in  claim 1  or  5 , wherein a heating gas and a gas to be heated are alternately passed therein so as to perform a heat-exchanging.  
     
     
         9 . A switching regenerative burner, comprising: at least one pair of honeycomb regenerators set forth in  claim 8 , wherein one honeycomb regenerator stores heat while the other honeycomb regenerator discharges heat, and a heat-exchanging operation is performed by switching each other.  
     
     
         10 . A heating furnace, comprising: the switching regenerative burner set forth in  claim 9 .  
     
     
         11 . A method of heating a substance to be heated, comprising the step of: heating the substance by using the heating furnace set forth in  claim 10 .  
     
     
         12 . A steel heating furnace, comprising: the switching regenerative burner set forth in  claim 9 .  
     
     
         13 . A method of heating a steel, comprising the step of: heating the steel by using the steel heating furnace set forth in  claim 12.