Composition for reducing the oxygen potential of slag

Abstract

A slag composition containing steelmaking slag and from about 0.3 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 8 to about 50 weight percent of ferrous oxide, from about 4 to about 20 weight percent of magnesium oxide, from about 8 to about 30 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 15 to about 70 weight percent of calcium carbide and from about 10 to about 50 weight percent silicon carbide, wherein the ratio of calcium carbide to silicon carbide is between 0.7 and 7.

1 . A slag composition comprised of steelmaking slag and from about 0.3 to about 10 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 8 to about 50 weight percent of ferrous oxide, from about 4 to about 20 weight percent of magnesium oxide, from about 8 to about 30 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 15 to about 70 weight percent of calcium carbide and from about 10 to about 50 weight percent of silicon carbide, wherein the ratio of calcium carbide to silicon carbide is between 0.7 and 7.   
     
     
         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 silicon carbide have similar particle size distributions. 
     
     
         4 . A slag composition comprised of steelmaking slag and from about 0.3 to about 10 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 8 to about 50 weight percent of ferrous oxide, from about 4 to about 20 weight percent of magnesium oxide, from about 8 to about 30 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 15 to about 70 weight percent of calcium carbide and from about 10 to about 50 weight percent of silicon carbide, wherein the ratio of calcium carbide to silicon carbide is between 0.7 and 7; and from about 5 to about 80 weight percent of a fluxing material selected from the group consisting of lime, calcium aluminate, calcium silicate, glass, calcium fluoride, by-product oxides, recycled slag, and combinations thereof.   
     
     
         5 . The slag composition as recited in  claim 4 , 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. 
     
     
         6 . An additive used in steel making comprised of reducing agents for adjusting ladle slag composition, said additive comprising about 15 to about 70 weight percent of calcium carbide and about 10 to about 50 weight percent of silicon carbide, wherein the ratio of calcium carbide to silicon carbide is between about 0.7 and about 7. 
     
     
         7 . The additive as recited in  claim 6  wherein the ratio of calcium carbide to silicon carbide is in the range 1.5 to 4.5. 
     
     
         8 . The additive as recited in  claim 7  wherein the ratio of calcium carbide to silicon carbide is in the range 2.3 to 3.5. 
     
     
         9 . The additive as recited in  claim 6 , 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. 
     
     
         10 . The additive as recited in  claim 9 , further comprising 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.