US2024167109A1PendingUtilityA1

Method for producing pig iron

Assignee: KOBE STEEL LTDPriority: Mar 26, 2021Filed: May 10, 2021Published: May 23, 2024
Est. expiryMar 26, 2041(~14.7 yrs left)· nominal 20-yr term from priority
C22B 1/243C21B 5/008C21B 5/001C21B 5/007C21B 9/10C22B 1/16C22B 1/245
49
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Claims

Abstract

A method for producing pig iron may use a blast furnace with a tuyere. Such a method may include: charging a first layer containing an iron ore material and a second layer containing coke alternately in the blast furnace; and reducing and melting the iron ore material in the charged first layer while injecting an auxiliary reductant into the blast furnace by hot air blown from the tuyere. An aggregate containing a reduced iron molded product obtained through compression molding of reduced iron may be blended into the first layer. The iron ore material may contain iron ore pellets as a principal material. An average basicity of the reduced iron molded product may be less than or equal to 0.5, and an average basicity of the iron ore pellets may be greater than or equal to 0.9.

Claims

exact text as granted — not AI-modified
1 . A method for producing pig iron using a blast furnace with a tuyere, the method comprising:
 charging a first layer comprising an iron ore material and a second layer comprising coke alternately in the blast furnace; and   reducing and melting the iron ore material in the first layer that is charged while injecting an auxiliary reductant into the blast furnace by hot air blown from the tuyere,   wherein an aggregate comprising a reduced iron molded product obtained through compression molding of reduced iron is blended into the first layer,   wherein the iron ore material comprises iron ore pellets as a principal material,   wherein an average basicity of the reduced iron molded product is less than or equal to 0.5, and   wherein an average basicity of the iron ore pellets is greater than or equal to 0.9.   
     
     
         2 . The method of  claim 1 , wherein a content of the iron ore pellets in the iron ore material is greater than or equal to 50% by mass. 
     
     
         3 . The method of  claim 1 , wherein the iron ore pellets are self-fluxing. 
     
     
         4 . The method of  claim 1 , wherein an R ratio of a consumption of the iron ore pellets to a consumption of the reduced iron molded product satisfies inequality (1): 
       
         
           
             
               
                 
                   
                     
                       R 
                       ≥ 
                       
                         
                           
                             [ 
                             
                               
                                 
                                   ( 
                                   
                                     C 
                                     / 
                                     S 
                                   
                                   ) 
                                 
                                 Critical 
                               
                               - 
                               
                                 
                                   ( 
                                   
                                     C 
                                     / 
                                     S 
                                   
                                   ) 
                                 
                                 HBI 
                               
                             
                             ] 
                           
                           
                             [ 
                             
                               
                                 
                                   ( 
                                   
                                     C 
                                     / 
                                     S 
                                   
                                   ) 
                                 
                                 P 
                               
                               - 
                               
                                 
                                   ( 
                                   
                                     C 
                                     / 
                                     S 
                                   
                                   ) 
                                 
                                 Critical 
                               
                             
                             ] 
                           
                         
                         × 
                         
                           
                             
                               ( 
                               
                                 % 
                                 ⁢ 
                                     
                                 
                                   SiO 
                                   2 
                                 
                               
                               ) 
                             
                             HBI 
                           
                           
                             
                               ( 
                               
                                 % 
                                 ⁢ 
                                     
                                 
                                   SiO 
                                   2 
                                 
                               
                               ) 
                             
                             P 
                           
                         
                       
                     
                     , 
                   
                 
                 
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
         wherein (C/S) is an average basicity, (% SiO 2 ) is a content of SiO 2  in % by mass, HBI, in subscript, is the reduced iron molded product, P is the iron ore pellets, and (C/S) Critical  is a critical basicity of the HBI. 
       
     
     
         5 . The method of  claim 1 , wherein the average basicity of the iron ore pellets is greater than or equal to 1.0. 
     
     
         6 . The method of  claim 1 , wherein the average basicity of the iron ore pellets is greater than or equal to 1.4. 
     
     
         7 . The method of  claim 1 , wherein the average basicity of the iron ore pellets is less than or equal to 2.0. 
     
     
         8 . The method of  claim 1 , wherein the content of the iron ore pellets in the iron ore material is greater than or equal to 90% by mass. 
     
     
         9 . The method of  claim 1 , wherein the content of the iron ore pellets in the iron ore material is greater than or equal to 100% by mass. 
     
     
         10 . The method of  claim 1 , wherein the iron ore pellets have a porosity resulting from open pores of a pore size of greater than or equal to 4 μm which is greater than or equal to 21%. 
     
     
         11 . The method of  claim 1 , wherein the iron ore pellets comprise MgO. 
     
     
         12 . The method of  claim 1 , wherein the iron ore pellets comprise MgO in at least 1% by mass. 
     
     
         13 . The method of  claim 1 , wherein the iron ore pellets comprise MgO in at least 1.5% by mass. 
     
     
         14 . The method of  claim 1 , wherein the iron ore pellets comprise MgO in no more than 4% by mass. 
     
     
         15 . The method of  claim 1 , wherein the iron ore pellets comprise MgO in no more than 3% by mass.

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