Technology of metallurgy for continuous scrap preheating electric arc furnace

Before putting the scrap steel into the electric arc furnace (EAF), using the high-temperature exhaust gas generating from EAF to preheat it can bring obvious energy-saving effect. Continuous scrap preheating EAF is different from the ordinary EAF in the way of the scrap steel continuous feeding, continuous preheating and melting, electric arc heating molten pool and then the molten pool melting scrap. In order to achieve high efficiency and energy-saving, ensure operating the equipment smoothly in the process and optimize the operating parameters, based on the technology features of the continuous scrap preheating EAF the research results indicate that more attention should be paid to the building of EAF lining, power supply, oxygen jet decarburization, slagging dephosphorization and so on;As the whole "flat molten bath", once the electric power is supplied, the electric arc heats the molten steel and at the same time the slag line is radiated by the high temperature electric arc, so the slag line must be protected and therefore full-time submerged arc operation by foaming slag is required;full-time "flat molten bath" and "change slag line" phenomenon need the thickness of magnesia-carbon brick on slag line increase about 300 mm, thus the resistance of slag line change can be increased;To determine the transformer parameters of the continuous preheating EAF, the following requirements should be considered:the scrap steel melting (voltage to be higher), the flat molten pool heating and heat preservation (voltage to be lower) by the electric arc. The selection of the voltage should based on the arc shielding state (scrap, or slag shelter state);in order to maximize energy-saving and environmental protection, the re-use technology of the waste heat must be applied, the pollution of dioxin deserves attention and research.