Desulphurization of ferrous materials using glass cullet

Abstract

The invention relates to a method for the preparation of a sodium-based reactive desulphurizing agent for use in molten ferrous materials. The source of sodium in the reactive desulphurizing agent is a glass cullet, a composition comprising of at least Na 2 O and SiO 2 . In a second embodiment of the invention, the glass cullet reactive desulphurizing agent also comprises of an alkali or an alkaline material or other materials, such as oxides of calcium, aluminum and magnesium. Preferred raw materials for the oxides of calcium, aluminum and magnesium are, respectively, lime, alumina and dolomite. The premixed solid reactive desulphurizing agent is brought in contact with the molten ferrous material, allowing the desulphurization or the double replacement of the iron sulphur to take place and produce a ferrous oxide. The sodium in the reactive desulphurizing agent is rendered resistant to combustion or evaporation on contact with the molten ferrous materials by the flux activity of the silica. A metallic solid, such as aluminum, is introduced into the molten ferrous material to complete the reduction of the ferrous oxide.

1 . A method for desulphurizing a molten ferrous material, comprises a reactive desulphurizing agent, said reactive desulphurizing agent further comprises of desulphurizing reactants, wherein at least one desulphurizing reactant contains a glass cullet.  
     
     
         2 . A method as defined in  claim 1 , wherein the glass cullet contains sodium.  
     
     
         3 . A method as defined in  claim 2 , wherein the glass cullet composition comprises: 
 a. a sodium oxide, Na 2 O; and a silicon oxide, SiO 2 ; wherein further,    b. x parts of Na 2 O and of y parts of SiO 2 ; wherein yet further,    c. the ratio, y/x, is anywhere from 0.5 to 5.    
     
     
         4 . A method as defined in  claim 1 , wherein the reactive desulphurizing agent comprises of a glass cullet and at least one other non-sodium desulphurizing reactant.  
     
     
         5 . A method as defined in  claim 4 , wherein the non-sodium desulphurizing reactants, in the reactive desulphurizing agent, are selected from a group of alkali earth metal compounds, alkaline metal compounds and other metals, compounds, composition and combinations thereof.  
     
     
         6 . Deleted.  
     
     
         7 . A method as defined in  claim 5 , wherein the desulphurizing agent comprises of a glass cullet and non-sodium desulphurizing reactants, wherein the sources for said non-sodium desulphurizing reactants are obtained from calcined materials: a lime, dolomite and an alumina.  
     
     
         8 . A method as defined in  claim 7 , wherein lime, dolomite and alumina provide: 
 a. calcium oxide;    b. magnesium oxide; and    c. aluminum oxide.    
     
     
         9 . A method as defined in  claim 8 , wherein the sulphur replacement reactants in the reactive desulphurization agent in the molten ferrous material comprise from 7 to about 50% by weight of sodium oxide, from 7 to about 50% by weight of silicon oxide, less than or equal to about 45% by weight of calcium oxide, less than or equal to about 8% by weight of magnesium oxide, and less than or equal to about 25% by weight of aluminum oxide.  
     
     
         10 . A method according to  claim 7 , wherein the reactive desulphurizing agent is placed in intimate contact with a molten ferrous material.  
     
     
         11 . A method according to  claim 10 , wherein at least one metallic solid is introduced into the desulphurized molten ferrous material to deoxidize or reduce the iron in the molten ferrous material.  
     
     
         12 . A method as defined in  claim 1 , wherein the reactive desulphurizing agent is placed in intimate contact with molten ferrous materials for the purpose of replacing the sulphur in the iron.  
     
     
         13 . A method according to  claim 12 , wherein at least one metallic solid is introduced into the desulphurized molten ferrous material to deoxidize or reduce the iron in the molten ferrous material.  
     
     
         14 . A method as defined in  claim 1 , wherein the ferrous material is selected from a group comprising: iron, pig iron, iron alloy, steels, mixtures thereof and other ferrous materials and wherein said ferrous material is contaminated with sulphur.  
     
     
         15 . A method derived from  claim 1 , wherein the desulphurizing agent is also a fluxing agent.  
     
     
         16 . A method as defined in  claim 15 , wherein the fluxing agent enhances the process of replacing of sulphur in the ferrous material.