At present, most electric arc steelmaking furnaces adopt the method of removing the furnace cover, feeding the furnace charge in batches from the furnace top, and directly heating the furnace charge with an electric arc.
The most common method of electric furnace steelmaking is cold charging, and cold charging can be divided into manual charging and mechanical charging according to the way steel materials are put into the furnace.
Mechanical charging is divided into trough, hopper, and basket charging due to different equipment.
At present, it is still the top loading of the basket that is widely used. The charging process is as follows: according to certain requirements, the charge is packed in the material basket pinned to the bottom with iron chains. When charging, first lift the furnace cover and rotate it to the rear side of the furnace or open the furnace body. Then use the crane to hoist the material basket from the furnace roof into the furnace, and then pull the overhead to discharge the material into the furnace. It usually takes 5 to 7 minutes to charge each time. In this way, when the electric furnace opens the furnace cover to charge, not only a large amount of dust generated by scrap steel and slag is generated, but also the dust spreads, polluting the working environment around the electric furnace. What is more important is the loss of a large amount of heat energy, (relevant information confirms: when the steel is just tapped, the furnace temperature is as high as above 1500°C, but at this time the heat dissipation is very fast, and it can drop below 800°C within a few minutes). This will inevitably prolong or increase the subsequent smelting time.
According to authoritative information, when the preheating temperature of scrap iron and steel before entering the furnace is 500°C, it can save 1/4 of electric energy, and when the temperature is 600-700°C, it can save 1/3 of electric energy. If the temperature reaches 900°C, only about 1/2 of the electric energy is needed for cold charging. This means that if the input power of the transformer remains unchanged, the melting period will be shortened in proportion. In addition, the introduction of hot charge into the furnace can also increase the stability of the arc and advance oxygen blowing and fluxing, which also shortens the melting period. Hot charging has no melting period, short smelting time and high productivity.
Continuous steelmaking technical equipment – DP scrap steel preheating electric furnace continuous charging device, this new type of steelmaking equipment has completely changed the conventional electric furnace top charging operation process with the furnace cover open. Continuous steelmaking technical one stop solution for LMM YOTAI
Its process procedure is: use special online equipment to continuously add metal raw materials (heavy and light scrap steel, pig iron, HBI, etc.) the process of. It can realize the continuous feeding of charge on the side of the electric furnace without opening the furnace cover, and the charge is directly loaded into the conveyor belt from the scrap yard or rail car. The scrap is then transported continuously and automatically to the electric furnace, while being preheated by the furnace exhaust gases in a preheating conveyor belt. Once preheated, the scrap is fed into an electric furnace where it is continuously melted by molten steel. At the same time, when tapping, generally keep 1/3~1/2 of the amount of remaining steel in the furnace. Immediately after the steel is tapped, the charge is sent continuously to continue the next smelting. The electrodes do not directly heat the charge. The main features of DP continuous conveying equipment are continuous feeding, continuous preheating and continuous smelting. It allows continuous flat bath operation which is a key advantage over conventional furnaces for direct arcing of steel!
Compared with other electric furnace processes, the DP series equipment process has the following obvious advantages: increased output (output increased by 8-10%), less power consumption (80-100KWh/t per ton of steel), less electrode consumption ( The electrode consumption of AC electric furnace is about 1.5–1.6kg/t), the dust treatment capacity is reduced by 20%-30%, the grid disorder is reduced, and the scrap steel yield is increased by about 2%. Less refractory materials and maintenance costs, lower production costs, and environmental impact are also minimized.
DP scrap steel preheating continuous conveying equipment is flexible and controllable in length (35-65 meters). Therefore, the equipment is suitable for the on-site technology and transformation of new steelmaking electric furnace workshops or old electric furnaces, and the economic benefits and surrounding environmental governance results are completely satisfactory.