Process and Apparatus for Producing Carbon Nanotube

Abstract

Carbon nanotubes are more efficiently produced with a simpler apparatus. The process, which is for producing carbon nanotubes by the combustion method, is characterized by comprising: a step in which a catalyst-supporting powder comprising a base powder and a catalyst supported on the surface thereof is prepared; a step in which the catalyst-supporting powder is deposited on a porous support ( 2 ) having through-holes through which a flame passes, so that the powder particles are held in the through-holes without tenaciously adhering to one another; a step in which the porous support ( 2 ) having the catalyst-supporting powder held thereon is disposed in a combustion oven ( 1 ) in which one end ( 1 b ) is open; and a step in which a carbon-containing flame is generated in a burner part ( 3 ) disposed at the other end ( 1 a ) of the combustion oven ( 1 ) and the flame is fed to the through-holes of the porous support ( 2 ) to produce carbon nanotubes on the surface of the catalyst-supporting powder present in the through-holes.

1 . A process for producing carbon nanotube by a combustion method, characterized in that it includes the steps of:
 preparing a catalyst-supporting powder comprising a base powder and a catalyst supported on the base powder;   allowing a porous support having through-pores that permit passage of a flame to hold said catalyst-supporting powder non-adherently within said through-pores of the porous support;   placing the porous support holding the catalyst-supporting powder inside a combustion oven having one open end; and   generating a carbon-containing flame in a burner portion disposed at the other end of said combustion oven and feeding the flame into the through-pores of the porous support so that carbon nanotubes are formed on a surface of the catalyst-supporting powder within the through-pores.   
     
     
         2 . The process for producing carbon nanotube as recited in  claim 1 , characterized in that a shielding member is disposed at said one end of the combustion oven for directing a part of a flow of said flame back toward the porous support. 
     
     
         3 . The process for producing carbon nanotube as recited in  claim 1 , characterized in that said base powder comprises a material soluble in an acid or alkali. 
     
     
         4 . The process for producing carbon nanotube as recited in  claim 3 , characterized in that said base powder comprises at least one of magnesium hydroxide, magnesium oxide, calcium hydroxide and calcium oxide. 
     
     
         5 . The process for producing carbon nanotube as recited in  claim 3 , characterized in that it further includes a step of extracting the catalyst-supporting powder, subsequent to formation of carbon nanotubes on its surface, from the porous support and contacting it to an acid or alkali to dissolve the base powder for recovery of the carbon nanotubes. 
     
     
         6 . The process for producing carbon nanotube as recited in  claim 1 , characterized in that said porous support comprises an entangled aggregate of metal or ceramic fibers, a stack of metal or ceramic meshes, a porous metal, or a porous ceramic. 
     
     
         7 . An apparatus for producing carbon nanotube by a combustion method, characterized in that it includes:
 a porous support having through-pores for non-adherently holding a catalyst-supporting powder comprising a base powder and a catalyst supported on a surface of the base powder,   a combustion oven having one open end and an interior portion for accommodation of said porous support, and   a burner portion disposed at the other end of the combustion oven;   and is operable to generate a carbon-containing flame in the burner portion and subsequently feed the flame into the through-pores of the porous support so that carbon tubes are formed on a surface of the catalyst-supporting powder within the through-pores.   
     
     
         8 . The apparatus for producing carbon nanotube as recited in  claim 7 , characterized in that it further includes a shielding member disposed at said one end of the combustion oven for directing a part of a flow of said flame back toward the porous support.