Process of recovering valuable metal

Abstract

A method for recovering a valuable metal including the steps of: recovering valuables from scraps containing the valuable metal; and removing at least part of carbon contained in the recovered valuables by heating the valuables in a non-oxidizable atmosphere, and a method for recovering a valuable metal including the steps of: thermally treating a melted mixture including the valuable metal and slag with a flux component to separate the valuable metal in a liquid phase from the slag in another liquid phase. In accordance with the present invention, the valuable metal in the scrap can be easily recovered.

What is claimed is:  
     
         1 . A method for recovering a valuable metal comprising the steps of: 
 recovering valuables from scraps containing the valuable metal; and    removing at least part of carbon contained in the recovered valuables by heating the valuables in a non-oxidizable atmosphere.    
     
     
         2 . The method as defined in  claim 1 , wherein the scraps containing the valuable metal are a scrapped nickel-hydrogen secondary cell.  
     
     
         3 . The method as defined in  claim 1 , wherein the valuables are selected from the group consisting of materials recovered from a positive electrode, materials recovered from a negative electrode and a mixture thereof.  
     
     
         4 . The method as defined in  claim 1 , wherein the non-oxidizable atmosphere is selected from the group consisting of an inert gas atmosphere, a hydrogen gas-atmosphere, a vapor atmosphere, an inert gas-vapor atmosphere and an inert gas-vapor-hydrogen gas atmosphere.  
     
     
         5 . The method as defined in  claim 1 , wherein the heating in the carbon-removing step is conducted at a temperature between 350 and 1050° C. for 5 minutes to 10 hours.  
     
     
         6 . The method as defined in  claim 1 , wherein the heating in the carbon-removing step is conducted while the valuables are stirred.  
     
     
         7 . The method for recovering the valuable metal as defined in  claim 1  further comprising the step of heating the recovered valuable metal for melting.  
     
     
         8 . A method for recovering a valuable metal comprising the steps of: 
 thermally treating a melted mixture including the valuable metal and slag with a flux component to separate the valuable metal in a liquid phase from the slag in another liquid phase.    
     
     
         9 . The method for recovering the valuable metal as defined in  claim 8 , wherein the flux component is boron oxide.  
     
     
         10 . The method for recovering the valuable metal as defined in  claim 8 , wherein the flux component is a mixture containing boron oxide and calcium oxide.  
     
     
         11 . A method for recovering a valuable metal comprising the steps of: 
 recovering valuables from scraps containing the valuable metal and slag;    removing at least part of carbon contained in the recovered valuables by heating the valuables in a non-oxidizable atmosphere to provide a melted mixture including the valuable metal and the slag; and    thermally treating the melted mixture with a flux component to separate the valuable metal in a liquid phase from the slag in another liquid phase.