Method for making steel in an electric arc furnace

Abstract

The invention relates to the field of metallurgy, and specifically to a method for producing steel in an electric arc furnace. A known method for making steel in an electric arc furnace includes, at least, loading, into the working space of a furnace, a solid metal charge and, at least, solid carbon-containing materials, melting the charge using electric arcs, carburizing the metal using the solid carbon-containing materials during melting, and outputting metal and slag from the furnace. It is proposed to conduct the melting process with the addition, to the working space of the furnace, of a high-carbon carburizer in the form of a liquid phase of iron recovered from the arc combustion zone for the additional carburization of the metal, wherein the high-carbon carburizer is obtained from iron oxides and carbonaceous material. The iron oxides and carbonaceous material are fed into the arc combustion zone, the dimensions of which are limited by D=dp+6del, where dp is the electrode pitch circle diameter and del is the diameter of an electrode. The total carbon content, in free and dissolved forms in the liquid iron phase, does not exceed 30%. The total amount of carburizer used in melting does not exceed 20% of the mass of the metal charge. The carburizer is fed continuously or periodically into the working space of the furnace during the charge melting process. The feeding of carburizer begins as charge melting begins. The use of the invention results in increased liquid metal output by means of regulating carbon content in the course of melting, increasing the carburization level of metal from the very beginning of melting, and reducing the loss of iron to slag and smoke.

1 . A method for steelmaking in an electric arc furnace comprising the following steps: at least loading a solid metal charge and at least solid carbon-bearing materials into the furnace proper; melting said charge with electric arcs; carburizing the metal with the solid carbon-bearing materials throughout the melting process; and tapping the metal and slag from the furnace, wherein during the melting process, a high carbon content carburizer is added into the furnace proper as a liquid phase of the iron reduced in the arc ignition zone, in order to additionally carburize the metal, wherein the high carbon content carburizer is obtained from iron oxides and a carbonaceous material. 
     
     
         2 . The steelmaking method of  claim 1 , wherein the total carbon content in free and dissolved forms in the liquid iron phase does not exceed 30%. 
     
     
         3 . The steelmaking method of  claim 1 , wherein the total carbon consumption for the smelting does not exceed 20% of the metal charge weight. 
     
     
         4 . The steelmaking method of  claim 1 , wherein iron said oxides and said carbonaceous material are injected into the arc ignition zone not exceeding D=(d p +6d el ) in size, where d p -electrode pitch circle diameter and d el -electrode diameter. 
     
     
         5 . The steelmaking method of  claim 1 , wherein the carburizer is injected into the furnace body continuously or periodically throughout the melting process of the charge. 
     
     
         6 . The steelmaking method of  claim 1 , wherein the start of the carburizer injection coincides with the start of the charge melting. 
     
     
         7 . The steelmaking method of  claim 1 , wherein the iron oxides and the carbonaceous material are injected into the arc-burning zone at the same time. 
     
     
         8 . The steelmaking method of  claim 1 , wherein prior to being injected into the furnace, the iron oxides and the carbonaceous material are premixed together and injected into the furnace as an intimate mixture. 
     
     
         9 . The steelmaking method of  claim 1 , wherein prior to being injected into the furnace, the iron oxides and the carbonaceous material are presintered and injected into the furnace sintered. 
     
     
         10 . The steelmaking method of  claim 1 , wherein prior to being injected into the furnace, the particles of the iron oxides and the carbonations material do not exceed 25 mm in size. 
     
     
         11 . The steelmaking method of  claim 1 , wherein the overall carbon content in free in dissolved forms in the liquid iron phase is at least 2%. 
     
     
         12 . The steelmaking method of  claim 1 , wherein the total amount of the carburizer used in the melting is at least 20% from the weight of the metal charge.