![]() These two reactions generate bubbles of CO which go upward and foam the slag. Oxygen also oxidized certain amount of iron and FeO is formed. Thus, a foaming slag is used to cover the arcs as more heat can be transferred to the bath and scrap.įoaming slag is formed by injection of carbon and oxygen, First, the carbon inside the bath is oxidized by oxygen blowing. The analysis of the bath chemistry allows the furnace operator to determine the amount of O2 needed to be blown during refining.Īt the start of the melting process, the arcs are covered by the scrap, so the radiation from the arcs to the lateral walls is low, but when the scrap starts melting, the heat efficiency decreases since the radiation to the walls increases. At this point, usually bath temperature and bath sample is taken. In this stage, there are gas – solid and solid –liquid phases in the bath.įinishing stage: The scrap is completely covered by the melt and only the solid –liquid phase exists until all the scrap is completely melted. Melting stage: The melting starts at the top surface of the scrap pile, and molten liquid penetrate towards the bottom of the furnace and its height increases whereas the height of the scrap pile decreases. In this stage the gas – solid phases exist. The temperature at the top increases to reach the melting temperature of the scrap. The heating is done by radiation, convection (due to the hot gas going through the scrap porosities) and conduction (due to contact points between scraps). Heating stage: The scrap is heated by the arc and oxy-fuel burners at the top of the furnace. The entire duration of the process can be divided into three main stages: Chemical energy is supplied through many sources which include oxy-fuel burners and oxygen lances. ![]() Electrical energy is supplied through the graphite electrodes and normally has a very large contribution in the melting phase. This energy can be electrical or chemical. Melting is carried out by supplying energy to the furnace interior. The EAF processing route could be summarized as follows: In the EAF, scrap and sometimes other raw materials such as DRI, HBI and pig iron are melted and converted into high quality steel by using high-power electric arcs formed between a cathode and one (for direct current DC) or three (for alternating current AC) graphite electrodes (anodes). PRIMARY METALLURGYĮlectric Arc Furnace (EAF) is a central part of the production route of the Electric Steelmaking process that is an alternative to the dominant Basic Oxygen Steelmaking (BOS) route.ĮAF is generally used to produce carbon steels and alloy steels primarily by recycling ferrous scrap. By using HBI both the availability of the smelting furnace and the safety of employees while charging can be increased. It also frequently breaks the electrodes. In contrast, scrap is most unwieldy and sometimes needs cutting down, an expensive process. HBI is compact and the briquettes are easy to feed into the furnace. Hot Briquetted Iron (HBI) is a premium form of DRI that has been compacted at a temperature greater than 650° C at time of compaction and has a density greater than 5,000 kilograms per cubic metre (5,000 kg/m3).
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