Further improvement in the performance is visualised by reducing electrical losses and recovering as much as possible the calorific value of outgoing carbon monoxide. The submerged arc furnace is made of carbon or magnesium refractory material as furnace lining and self-baking electrodes. The reduction of silica is found to account for just 47♶% of the total energy that is added via the calorific value of carbon and the electricity in producing the alloy. It might result in a saving of more than 3000 kWh/t of Fe-80Si alloy. The recycling of silicon monoxide is promoted by maintaining a bed of a certain height so that evolved gases are cooled owing to heat exchange between the gas and solid phases. Mass and enthalpy balances are used to determine the carbon and electricity requirements of the process. Submerged arc furnace production of pig iron and foundry iron has been practiced in some industrialized countries as late as the 1950s. It is important to know the activity coefficient of silicon in the alloy as a function of temperature, and the silicon content of the alloy using literature data. The sum of partial pressures of carbon monoxide and silicon monoxide must equal the applied pressure of 1 atm at the smelting temperature.
Submerge arc furnace free#
Thermodynamic data on the standard free energy of formation of species are used in the study to calculate the required smelting temperatures at various silicon contents of the alloy. Higher grades of ferrosilicon alloy may be produced owing to the reactions occurring between silicon carbide and silica at temperatures above 1810 K. The submerged arc furnace has been widely used in the ferroalloy industry and has great energy saving potential.
The rest of the carbon will be consumed to transform silica to silicon carbide at ~ 1810 K. In the presence of iron, silica will be reduced by carbon to give a maximum of ~ 22 wt% silicon in the liquid alloy. Ferrosilicon alloys are commonly manufactured in submerged electric arc furnaces with little slag.
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