Process for recovery of iron from copper slag

Abstract

The present invention relates to a process for recovery of iron from copper slag. This invention particularly relates to a process for recovery of iron from a waste like granulated copper slag generated during the production of copper from its ores by a pyrometallurgical method. The present invention will be useful for solving the ecological and environmental issues with an added economic advantage of utilising the dump slag generated in the copper plants. Novelty of the present invention is process for the preparation of value added products viz grinding grade cast iron using copper slag generated during the processing of copper concentrate which otherwise is considered as a waste. Other novel features of the inventions are creating a homogeneous mixture of slag, reductant and flux so that reaction kinetics is more than conventional process. The reductant is used in such a way so that maximum recovery of iron can take place.

1 . A process for the recovery of iron from copper slag which comprises: 
 i. selecting and grinding the copper slag to [the] a size in the range of 2-15 mm.    ii. mixing homogeneously copper slag, a reductant and a flux in the ratio range between 20:1:4 to 20:3:10.    iii. creating a molten pool of metal having a [carbon] percentage of carbon in the range of 3-4.5% in a [arc] furnace by a known method,    iv. inducting the mixture obtained in step (ii) in the molten metal pool at a slow rate so that vigorous reaction can be avoided,    v. maintaining the temperature of the furnace in the range of 1350 to 1500° for a period ranging between 1-3 hours,    vi. sprinkling reductant material into the molten bath so that foam can be avoided, and    vii. tapping the melt from the furnace and casting by a known method.    
     
     
         2 . A process according to  claim 1 , wherein the copper slag used in the process [have] has the following composition range:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Cu (%) 
                      0-0.523 
                 
                     
                   Silica (%) 
                   25-35 
                 
                     
                   Lime (%) 
                    3-10 
                 
                     
                   Fe (%) 
                   30-50 
                 
                     
                   Cd (ppm) 
                      0-0.005 
                 
                     
                   Co (ppm) 
                   2-6 
                 
                     
                   Ni (ppm) 
                     0-0.6 
                 
                     
                   Pb (ppm) 
                    2-10 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         3 . A process according to claim[s]  1 [- 2 ] wherein the reductant material are selected from graphite, petroleum coke and like materials and have a size in the range between 0.2 to 10 mm.  
     
     
         4 . A process according to claim[s]  1 [- 3 ] wherein the addition of a reductant material [are] is made through the following three stages: 
 stage-1: 15 to 20 weight % of the reductant is added initially after completely melting [of] the metal pool,    stage-2: 50 to 60 weight % of the reductant is mixed with granulated slag and flux,    stage-3: 30 to 35 weight % of the reductant is added during the melting process to avoid foaming.    
     
     
         5 . A process according to claim[s]  1 [- 4 ], [wherein the quantity of the molten pool] the quantity [created amount] of the molten pool is [of] 10 to 20 of the volume % [of furnace] capacity of the furnace.  
     
     
         6 . A process according to claim[s]  1 [- 5 ] wherein the flux [used are] employed is selected from the group consisting of the oxides and carbonates of calcium and magnesium.  
     
     
         7 . The process according to claim[s]  1 [- 6 ] wherein the [obtained] products obtained are a [is] grinding grade of cast iron and like and the recovery rate of iron is in the range of 75 to 85 weight % of the iron values.  
     
     
         8 . A process according to  claim 2 , wherein the reductant material are selected from graphite, petroleum coke and like materials and have a size in the range between 0.2 to 10 mm.  
     
     
         9 . A process according to  claim 2 , wherein the addition of a reductant material [are] is made through the following three stages: 
 stage-1: 15 to 20 weight % of the reductant is added initially after completely melting [of] the metal pool,    stage-2: 50 to 60 weight % of the reductant is mixed with granulated slag and flux,    stage-3: 30 to 35 weight % of the reductant is added during the melting process to avoid foaming.    
     
     
         10 . A process according to  claim 3 , wherein the addition of a reductant material [are] is made through the following three stages: 
 stage-1: 15 to 20 weight % of the reductant is added initially after completely melting [of] the metal pool,    stage-2: 50 to 60 weight % of the reductant is mixed with granulated slag and flux,    stage-3: 30 to 35 weight % of the reductant is added during the melting process to avoid foaming.    
     
     
         11 . A process according to  claim 2 , [wherein the quantity of the molten pool] the quantity [created amount] of the molten pool is [of] 10 to 20 of the volume % [of furnace] capacity of the furnace.  
     
     
         12 . A process according to  claim 3 , [wherein the quantity of the molten pool] the quantity [created amount] of the molten pool is [of] 10 to 20 of the volume % [of furnace] capacity of the furnace.  
     
     
         13 . A process according to  claim 4 , [wherein the quantity of the molten pool] the quantity [created amount] of the molten pool is [of] 10 to 20 of the volume % [of furnace] capacity of the furnace.  
     
     
         14 . A process according to  claim 2 , wherein the flux [used are] employed is selected from the group consisting of the oxides and carbonates of calcium and magnesium.  
     
     
         15 . A process according to  claim 3 , wherein the flux [used are] employed is selected from the group consisting of the oxides and carbonates of calcium and magnesium.  
     
     
         16 . A process according to  claim 4 , wherein the flux [used are] employed is selected from the group consisting of the oxides and carbonates of calcium and magnesium.  
     
     
         17 . A process according to  claim 5 , wherein the flux [used are] employed is selected from the group consisting of the oxides and carbonates of calcium and magnesium.  
     
     
         18 . The process according to  claim 2 , wherein the [obtained] products obtained are a [is] grinding grade of cast iron and like and the recovery rate of iron is in the range of 75 to 85 weight % of the iron values.  
     
     
         19 . The process according to  claim 3 , wherein the [obtained] products obtained are a [is] grinding grade of cast iron and like and the recovery rate of iron is in the range of 75 to 85 weight % of the iron values.  
     
     
         20 . The process according to  claim 4 , wherein the [obtained] products obtained are a [is] grinding grade of cast iron and like and the recovery rate of iron is in the range of 75 to 85 weight % of the iron values.  
     
     
         21 . The process according to  claim 5 , wherein the [obtained] products obtained are a [is] grinding grade of cast iron and like and the recovery rate of iron is in the range of 75 to 85 weight % of the iron values.  
     
     
         22 . The process according to  claim 6 , wherein the [obtained] products obtained are a [is] grinding grade of cast iron and like and the recovery rate of iron is in the range of 75 to 85 weight % of the iron values.