Production of Ferrochromium Alloys.
U S Pat 4 306 905 1981 Dec; :
Powdered chromite ore is mixed with a carbonaceous reductant, and with cao as an optional promoter, and pelletized. The porous pellets are heated in vacuum (0.4-16 Torr) to 1,300 deg-1,350 deg c for reduction. The hot reduced product is melted to the desired ferroalloy composition in the presence of fluxes. Thus, extruded pellets were manufactured from a mixture of powdered graphite and chromite concentrate (-400 mesh each), with or without 13 g cao/g of chromite. The pellets were heated to 1,300 deg c at 1 torr. Reduction of 100 pct of cr and fe was attained in 7 h with cao, compared with 16 h without cao.
U.S. Pat. 4,306,905, Dec. 22, 1981; Chem. Abstr. 96:38,831S