What Is a Furnace Roller?

The furnace body consists of upper and lower furnace bodies, furnace doors, furnace door lifting mechanisms, EBT tapping mechanisms, etc. The lower furnace body adopts a cylindrical structure welded by steel plates. The upper furnace body (referring to the part above 400mm on the slag line) is generally a water-cooled furnace with a tube-to-tube structure welded with seamless steel pipes under high power conditions. The wall and its inlet and outlet water are provided with ball valves.

In the electric furnace, due to the high temperature of arc discharge, the charge is melted and a reduction reaction is performed to form an alloy. A barrel-shaped hearth is formed by a furnace lining in the furnace body, and a three-phase electrode is vertically arranged in the upper part of the furnace in a regular triangle shape. The lower part of the electrode is the main reaction area, and the electrical energy is converted into thermal energy through the arc and resistance. The geometrical dimensions such as the furnace diameter, depth, and the relative positions of the electrodes and the furnace have a great influence on the current distribution and temperature distribution in the furnace. Because the reaction temperature is as high as over 2000 ° C, the volume of the furnace body is generally larger than the reaction space, so a layer of furnace charge is left between the reaction zone and the furnace lining to protect the furnace lining.

The furnace body consists of a furnace shell, a furnace lining and a tap hole. Most of the furnace shells are in the shape of barrels or inverted cones. They are made of 16-25mm thick boiler steel plates and are equipped with horizontal reinforcement rings and horizontal and vertical reinforcement ribs for reinforcement. The tap slot is made of welded steel or cast steel.

The furnace body is made of carbon brick lining. It is required that thin steel plates must be welded at the welding interface of the furnace shell to seal the joints to prevent the joints from being loosened when the furnace shell is heated, and the carbon bricks are oxidized due to air leakage. The bottom surface of the furnace shell is horizontal. The furnace body of the fixed furnace floats on the I-beams arranged at intervals, so that when heated, the furnace shell and I-beams can expand freely without affecting each other. An air passage at the bottom of the furnace is formed between the I-beams, which is beneficial to the cooling of the furnace bottom. ^[1]

The effects of high temperature thermal corrosion, mechanical scouring and chemical erosion inside the ore heating furnace, so that the use of any refractory materials can not avoid the damage of the furnace lining. High power density and high stirring strength of the molten pool are the main measures to strengthen the multi-slag ore hot furnace, which in turn makes the working conditions of the lining closer to or exceeds the range of performance that the refractory can withstand. It is difficult to adapt to the improvement of the material alone. Demand for process development. In recent years, the research on the furnace lining in the metallurgical industry has shifted from simply pursuing materials to adopting strong cooling measures to extend the life of the furnace lining. People fully understood the role of heat transfer and insulation of the furnace lining, balanced the gain and loss of heat loss and furnace lining loss, and began to attach importance to the cooling effect of the furnace lining.

The traditional furnace design often increases the thickness of the furnace lining and insulation layer in order to improve the thermal efficiency of the electric furnace. However, due to the internal thermal balance of the furnace, the temperature of the furnace wall and the bottom of the furnace is too high, and the added furnace lining is eventually consumed, and it cannot play a protective role. The use of measures to increase the diameter of the furnace shell, in addition to increasing the cost of the furnace lining, will also increase the distance from the furnace eye to the high temperature melt in the furnace, which also causes difficulties for the furnace. Practice has proven that increasing the thermal conductivity of the lining material is the most effective measure to extend the life of the lining. Although this design will have a lot of heat loss through the furnace lining and the thermal efficiency of the electric furnace will be reduced, the furnace lining with good thermal conductivity has no significant impact on the unit power consumption of the product.

This new concept of furnace lining design has been applied to smelting electric furnaces. Its basic principle is that no matter how high the temperature and how aggressive the chemical melt, the melt will be transformed into a solid with minimal erosion under a certain cooling intensity; the fake furnace lining formed by solidified metal and slag is a high temperature melt Plays a good protective role. The key technology is the choice of cooling strength, cooling element and cooling medium, as well as the design of the interface between the cooling element, the refractory material of the mechanical equipment and the melt. The technical features of the new concept are: thinning the furnace wall, intensifying cooling, reducing the temperature of the furnace wall; hanging the slag furnace wall, stable and reasonable slag skin, and reducing heat loss. ^[3]

The converter furnace body malfunctions. It is common for the refractory material to burn through or drop bricks, which causes the furnace shell to turn red or leak. The furnace director immediately turns the air eye area out of the melt surface and performs the air stop operation.

(1) Partial redness on the surface of the furnace shell

The eye area and the end wall are red. Spray water or ventilate heat on the surface immediately.

The part of the furnace mouth is red, increase the amount of quartz stone and cold material, and use the melt spray to hang the slag by itself.

(2) Partial penetration

At the location of the wind eye area, the furnace can be turned out of the liquid surface, blocked with asbestos rope and magnesium mud, and then continued to be blown. After being discharged from the furnace, the furnace is filled with magnesium mud or processed into the furnace.

At the position of the furnace body or end wall, immediately dump the melt into a ladle or directly discharge it into a safety pit, and the furnace must be stopped for maintenance.

At the position of the furnace mouth, increase the input of quartz stone and cold material, and control the air supply so that the slag is leaked by the burned and leaked parts.

Turn the furnace body immediately after turning black, redness or perforation in a large area, and pour the melt into the ladle or directly into the safety pit for shutdown and maintenance.