Method For Producing Metal

Abstract

A method for producing a metal by an electrolytic process using an yttria-containing porous ceramic body as a diaphragm is provided; the calcium formed by electrolysis cannot pass through the diaphragm, hence the back reaction can be effectively inhibited. Preferably, to be used is a diaphragm comprising a porous ceramic body having a purity of yttrium of 90 mass % or more (more preferably, 99% or more), a porosity of 1% or more and a pore diameter of 20 μm or less, and having a thickness of 0.05-50 mm and a metal halide is used as the electrolytic bath. The method can be utilized for producing metals such as calcium or rare earth elements, in particular. For example, when the method is applied to the production of calcium, metallic calcium can be produced with ease and at low cost without the need for enormous heat energy.

1 . A method for producing a metal by an electrolytic process, comprising using an yttria-containing porous ceramic body as a diaphragm. 
     
     
         2 . The method for producing a metal as claimed in  claim 1 , wherein said porous ceramic body is made of a material which is mainly constituted by yttria. 
     
     
         3 . The method for producing a metal as claimed in  claim 1 , wherein a metal halide is used as an electrolytic bath. 
     
     
         4 . The method for producing a metal as claimed in  claim 1 , wherein said porous ceramic body has a porosity of not less than 1%. 
     
     
         5 . The method for producing a metal as claimed in  claim 1 , wherein said diaphragm has a thickness of 0.05-50 mm. 
     
     
         6 . The method for producing a metal as claimed in  claim 1 , wherein said porous ceramic body has a pore diameter of not more than 20 μm. 
     
     
         7 . The method for producing a metal as claimed in  claim 1 , wherein said porous ceramic body has an yttria purity of not less than 90 mass %. 
     
     
         8 . The method for producing a metal as claimed in  claim 1 , wherein a current density in electrolysis is 0.1-100 A/cm 2 . 
     
     
         9 . A method for producing a metal, comprising using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 1  to obtain metallic calcium or a molten salt containing metallic calcium. 
     
     
         10 . The method for producing a metal as claimed in  claim 9 , wherein said metallic calcium is obtained in the form of a solid. 
     
     
         11 . The method for producing a metal as claimed in  claim 9 , wherein said metallic calcium is obtained in the form of a molten substance. 
     
     
         12 . A method for producing a metal, comprising using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 2  to obtain metallic calcium or a molten salt containing metallic calcium. 
     
     
         13 . A method for producing a metal, comprising using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 3  to obtain metallic calcium or a molten salt containing metallic calcium. 
     
     
         14 . A method for producing a metal, comprising using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 4  to obtain metallic calcium or a molten salt containing metallic calcium. 
     
     
         15 . A method for producing a metal, comprising using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 5  to obtain metallic calcium or a molten salt containing metallic calcium. 
     
     
         16 . A method for producing a metal, comprising using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 6  to obtain metallic calcium or a molten salt containing metallic calcium. 
     
     
         17 . A method for producing a metal, comprises using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 7  to obtain metallic calcium or a molten salt containing metallic calcium. 
     
     
         18 . A method for producing a metal, comprising using a calcium salt or a mixed salt containing calcium salt in a molten state as an electrolytic bath and applying the method for producing a metal as defined in  claim 8  to obtain metallic calcium or a molten salt containing metallic calcium.