Composition for reducing steelmaking slag

Abstract

A slag composition containing steelmaking slag and from about 0.5 to about 10 weight percent of reducing agent. The steelmaking slag contains from about 20 to about 55 weight percent of calcium oxide, from about 10 to about 50 weight percent of ferrous oxide, from about 5 to about 20 weight percent of magnesium oxide, from about 5 to about 20 weight percent of silicon oxide, from 0.5 to about 10 weight per cent aluminum oxide, and from about 0.5 to about 10 weight percent of manganese oxide. The reducing agent contains from about 5 to about 80 weight percent of calcium carbide and from about 10 to about 70 weight percent of an admixture containing silicon or titanium or silicon carbide or combinations thereof.

1 . A slag composition comprised of steelmaking slag and from about 0.5 to about 15 percent of reducing agent by total weight of steelmaking slag and reducing agent, wherein: 
 a. said steelmaking slag is comprised of from about 20 to about 55 weight percent of calcium oxide, from about 10 to about 50 weight percent of ferrous oxide, from about 5 to about 20 weight percent of magnesium oxide, from about 5 to about 20 weight percent of silicon oxide, from 0.5 to about 10 weight per cent aluminum oxide, and from about 0.5 to about 10 weight percent of manganese oxide; and    b. said reducing agent is comprised of from about 5 to about 80 weight percent of calcium carbide and from about 10 to about 70 weight percent of a material selected from the group consisting of silicon, titanium, silicon carbide, and mixtures thereof.    
   
   
       2 . The slag composition as recited in  claim 1 , wherein said reducing agent is provided in the form of particles, and at least about 90 weight percent of said particles are within a size range of from about 0.1 to about 0.7 inches.  
   
   
       3 . The slag composition as recited in  claim 2 , wherein said calcium carbide and said material selected from the group consisting of silicon, titanium, and silicon carbide, and mixtures thereof have similar particle size distributions.  
   
   
       4 . The slag composition as recited in  claim 1 , wherein the source of said titanium is titanium oxide.  
   
   
       5 . The slag composition as recited in  claim 1 , wherein the source of said titanium is ferrotitanium.  
   
   
       6 . The slag composition as recited in  claim 1 , wherein the source of said silicon is calcium silicon.  
   
   
       7 . A slag composition comprised of steelmaking slag and from about 0.5 to about 15 percent of reducing agent by total weight of steelmaking slag and reducing agent, wherein: 
 a. said steelmaking slag is comprised of from about 20 to about 55 weight percent of calcium oxide, from about 10 to about 50 weight percent of ferrous oxide, from about 5 to about 20 weight percent of magnesium oxide, from about 5 to about 20 weight percent of silicon oxide, from 0.5 to about 10 weight per cent aluminum oxide, and from about 0.5 to about 10 weight percent of manganese oxide; and    b. said reducing agent is comprised of from about 5 to about 80 weight percent of calcium carbide and from about 10 to about 70 weight percent of a first material selected from the group consisting of silicon, titanium, silicon carbide, and mixtures thereof; and from about 5 to about 80 weight percent of a second material including a fluxing material selected from the group consisting of lime, calcium aluminate, calcium silicate, glass, calcium fluoride, by-product oxides, recycled slag, or combinations thereof.    
   
   
       8 . The slag composition as recited in  claim 7 , wherein said reducing agent is provided in the form of particles, and at least about 90 weight percent of said particles are within a size range of from about 0.1 to about 0.7 inches.  
   
   
       9 . The slag composition as recited in  claim 7 , wherein the source of said titanium is titanium oxide.  
   
   
       10 . The slag composition as recited in  claim 7 , wherein the source of said titanium is ferrotitanium.  
   
   
       11 . The slag composition as recited in  claim 7 , wherein the source of said silicon is calcium silicon.  
   
   
       12 . The slag composition as recited in  claim 7 , wherein the source of said calcium aluminate is recycled ladle slag.  
   
   
       13 . The slag composition as recited in  claim 7 , wherein the source of said calcium silicate is recycled ladle slag.  
   
   
       14 . An additive used in steel making for making a ladle slag composition, said additive comprising about 5 to about 60 weight percent of a first reducing agent, and about 10 to about 70 weight percent of a second reducing agent, wherein: 
 a. said first reducing agent consists essentially of calcium carbide; and    b. said second reducing agent is selected from the group consisting of silicon, titanium, silicon carbide, and mixtures thereof.    
   
   
       15 . The additive as recited in  claim 14 , wherein said reducing agents are provided in the form of particles, and at least about 90 weight percent of said particles are within a size range of from about 0.1 to about 0.7 inches.  
   
   
       16 . The additive as recited in  claim 15 , wherein said calcium carbide and said second reducing agent selected from the group consisting of silicon, titanium, and silicon carbide, and mixtures thereof have similar particle size distributions.  
   
   
       17 . The additive as recited in  claim 14 , wherein the source of said titanium is titanium oxide.  
   
   
       18 . The additive as recited in  claim 14 , wherein the source of said titanium is ferrotitanium.  
   
   
       19 . The additive as recited in  claim 14 , wherein the source of said silicon is calcium silicon.  
   
   
       20 . The additive as recited in  claim 14 , further comprising a fluxing material selected from the group consisting of lime, calcium aluminate, calcium silicate, glass, calcium fluoride, by-product oxides, steelmaking slag, recycled slag, or combinations thereof.