Smelting process of high-carbon ferrochrome
The smelting methods of high-carbon ferrochrome are blast furnace method, electric furnace method, plasma furnace method, etc. The use of blast furnace can only produce special pig iron with chromium content of about 30%. At present, most of the high-carbon ferrochrome with high chromium content are smelted in the mineral-heated furnace using the melt method.
The basic principle of smelting high-carbon ferrochrome by the electric furnace method is the reduction of chromium and iron oxides in chromite ore with carbon. Carbon reduction of chromium oxide generates Cr2C2 at a starting temperature of 1373K and Cr7C3 at a reaction starting temperature of 1403K, while the reduction generates chromium at a reaction starting temperature of 1523K, thus the carbide of chromium is obtained in the carbon reduction of chromite, not chromium metal. The carbon content in ferrochrome depends on the reaction temperature. It is easier to generate carbides with a high carbon content than to generate carbides with a low carbon content.
Third, the raw materials for smelting high-carbon ferrochrome.
The raw materials for smelting high-carbon ferrochrome are chrome ore, coke and silica.
1, chrome ore in Cr2O3 ≥ 40%, Cr2O3 / ∑ FeO ≥ 2.5, S < 0.05%, P < 0.07%, MgO and Al2O3 content can not be too high, particle size 10 ~ 70mm, such as refractory ore, particle size should be appropriate smaller.
2, coke requirements containing not less than 84% fixed carbon, ash less than 15%, S <0.6%, particle size 3 ~ 20mm.
3, silica requires SiO2 ≥ 97%, Al2O3 ≤ 1.0%, good thermal stability, without clay, particle size 20 ~ 80mm.
