Method for recovering valuable metals

Abstract

Provided is a method in which, when discarded batteries such as lithium-ion batteries are treated by a dry process, slag having a reduced viscosity is obtained to heighten the recovery of valuable metals. The method for recovering valuable metals includes a dry process (S 20 ) which includes a melting step (ST 21 ), a slag separation step (ST 22 ), and an alloy separation step (ST 23 ), the slag having an aluminum oxide content of 5 mass % or higher but less than 20 mass % and an iron content in terms of metallic iron amount of 20-40 mass %. Furthermore, silicon oxide and calcium oxide are added as a flux in the melting step (ST 21 ) so that the slag has a melting point of 1,400° C. or lower, and the melting step (ST 21 ) is conducted at 1,400° C. or lower. Thus the recovery of the alloys can be heightened.

1 - 5 . (canceled) 
     
     
         6 . A method for recovering valuable metals from waste batteries, the method comprising:
 a roasting step for roasting the waste batteries at a temperature of higher than or equal to 300° C. and lower than 600° C.;   an oxidation step for carrying out an oxidation treatment by roasting the waste batteries roasted in the roasting step at a temperature of from 1100° C. to 1200° C.; and   dry step for melting the waste batteries after the oxidation step, and separately collecting slag and an alloy of valuable metals.   
     
     
         7 . The method for recovering valuable metals according to  claim 6 , wherein the melting step in the dry step further comprises an additional oxidation step for carrying out an additional oxidation treatment. 
     
     
         8 . The method for recovering valuable metals according to  claim 6  or  7 , wherein the roasting step and the oxidation step are carried out in a single heating furnace by sequentially changing the temperature inside the single heating furnace. 
     
     
         9 . The method for recovering valuable metals according to  claim 6  or  7 , wherein the roasting step and the oxidation step are carried out in a single heating furnace by dividing the interior of the single heating furnace into plural zones, and heating the respective zones to different temperatures. 
     
     
         10 . The method for recovering valuable metals according to any one of  claims 6  to  9 , wherein the waste batteries are a battery pack equipped with a plastic casing.