Medium, low, micro - carbon ferrochrome silicon chromium alloy, chromite and lime as materials, with 1500 ~ 6000 kVA furnace desilication, select high alkalinity slag operation (CaO/SiO2 for 1.6 ~ 1.8). Low and micro - carbon ferrochrome is also produced by heat transfer method. Two electric furnaces are used for the production, one for the exercise of silicon-chromium alloy, and one for the melting of slag, which is composed of chromium ore and lime. The response of the essence is divided into two stages in two buckets: (1) slag slag furnace slag into the top of the bucket, the other bucket has begun to desilication of silicon chromium alloy, because the excess amount of slag oxidant is large, desilication is abundant, can be obtained containing silicon less than 0.8%, containing carbon as low as 0.02% of micro carbon ferrochrome. The reverberated slag in the top bucket (containing about 15% Cr2O3) is moved to the second bucket, and the silicon and chromium alloy (containing 45% silicon) made by the electric furnace is heated and added into the slag, after the reverberation, the silicon and chromium alloy (containing about 25% silicon) is started desilication, and added into the top bucket for further desilication, and the slag containing Cr2O3 less than 2 ~ 3% can be thrown away.
Oxygen blowing method in essence, low carbon ferrochrome, with liquid carbon ferrochrome as material, blowing to the molten pool to participate in a small amount of lime, fluorite slag, iron before adding silicon chromium alloy or ferrosilicon to recover the slag in chromium. The smelting of micro-carbon ferrochrome is possible only at a certain vacuum.
Vacuum decarburization process is pithy, solid state for the material with fine grinding of high carbon ferrochrome, part of the fine grinding of high carbon ferrochrome by oxidizing roasting as oxidant, with water glass or other adhesives, pressure ball, after low temperature drying, the car type vacuum furnace, the vacuum degree 0.5 ~ 10 mm hg, temperature of 1300 ~ 1400 ℃ heat recovery under 35 ~ 50 hours, available carbon is less than 0.03% even less than 0.01% of low carbon ferrochrome. Exercise in a recovery furnace, using coke as a recovery agent and silica or bauxite as a flux. The composition of slag is SiO227 ~ 33%, MgO30 ~ 34%, Al2O326 ~ 30%, Cr2O3 < 9.0%. Because it is made of chromium carbide, commodities contain 4 to 9% carbon. Modern exercise chromite recovery furnace capacity of 10,000 ~ 48,000 kVA, usually choose to close fixed, exercise power consumption of 3000 ~ 4000 kw • hour/ton. The electric furnace for exercising si-Cr alloy is similar to the electric furnace for restoring ferrochrome. There are two methods: one step and two step. One - step exercise with chromite, silica and coke plus flux. The two-step method selects carbon ferrochrome, silica and coke as materials to exercise without slag, and the exercise process is roughly similar to the production of ferrosilicon. Exercise power consumption per ton of 3000 ~ 4000 kw • hour around.