Method for improving efficiency of hot metal briquetting

Abstract

This invention belongs to the field of iron and steel smelting technology, and relates to a method for improving the efficiency of molten iron casting. The method involves selecting molten iron with stable blast furnace conditions, a temperature of 1500℃~1520℃, and a molten iron composition (by mass percentage): C: 4.15%~4.3%, Si: 0.3%~0.5%; blast furnace slag basicity (CaO / SiO2): 1.15~1.25; removing slag before casting, adding a heat-insulating agent at a rate of 0.6~1.0 kg / ton of molten iron, and evenly covering the surface of the molten iron; and employing a casting iron spout construction method. The process involves: using 10-20mm thick steel plates for the spout template, laying a layer of asbestos board on top, and then ramming a refractory layer at least 200mm thick onto the asbestos board. The ramming material contains 20%-30% electrode paste or asphalt. Refractory bricks are then laid on top of the rammed layer, and the joints between the bricks are filled with ramming material containing 20%-30% electrode paste or asphalt. Coke dust is added to the peat to increase its refractoriness, achieving a fixed carbon content of 30%. The spray nozzle is changed from a nozzle hole to a spray slit, and the peat slurry is evenly sprayed into the cast iron mold. This ensures the fluidity of the molten iron, reduces the time spent cleaning the cast iron spout to prevent blockages and crusting, and extends the service life of the cast iron spout.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel smelting technology and relates to a method for improving the efficiency of molten iron casting. Background Technology

[0002] A cast iron machine is a device for casting pig iron blocks. It consists of a circulating chain conveyor belt containing a series of molds. Molten iron is poured one by one into the moving molds at one end, cools during the journey, and solidifies automatically from the molds as it moves in the opposite direction at the tail end of the machine. The cast iron machine is a crucial piece of equipment in blast furnace iron casting; its operational stability directly affects the continuity of cast iron production and the improvement of casting efficiency.

[0003] The process of casting molten iron blocks is as follows: Locomotives transport molten iron ladles or mixed iron ladles filled with molten iron from the blast furnace to the iron casting machine workshop via railway locomotives or automobiles (the overhead crane lifts the molten iron ladles filled with molten iron from the blast furnace to the KR desulfurization area to remove the blast furnace slag, and then lifts them to the iron casting area). The tilting mechanism tilts the molten iron ladle, and the molten iron flows into the iron casting machine mold through the molten iron flow channel. The iron casting machine mold filled with molten iron moves slowly upward under the drive of the chain belt. During the transportation process, the cooling device sprays cooling water onto the already crusted iron blocks to accelerate the cooling of the iron blocks. The iron blocks fall off at the star wheel at the head of the machine and are slid into the transport car by the chute and transported out. Individual iron blocks that are not easy to fall off are cleaned and removed by the iron removal device. When the chain belt returns, in order to facilitate the demolding of the iron blocks, peat slurry is continuously sprayed into the iron casting machine mold during the operation of the iron casting machine.

[0004] Casting machines, which mold molten iron from blast furnaces into iron blocks, are a means of maintaining the balance between the iron and steel interface in blast furnaces and converters. The efficiency of demolding the cast iron blocks, the lifespan of the casting nozzle, and the flow of molten iron all constrain the production efficiency of the casting machine. Therefore, improving the efficiency of molten iron casting has always been a key research focus. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to solve the above problems and provide a method for improving the efficiency of molten iron casting.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method to improve the efficiency of molten iron casting involves selecting molten iron with stable blast furnace conditions, a molten iron temperature of 1500℃~1520℃, and a molten iron composition by mass percentage: C: 4.15%~4.3%, Si: 0.3%~0.5%; blast furnace slag basicity CaO / SiO2: 1.15~1.25; removing floating slag before casting, and adding heat-insulating agent at a rate of 0.6~1.0 kg / ton of molten iron to evenly cover the surface of the molten iron.

[0008] The cast iron spout construction process is as follows: the spout template is made of 10-20mm steel plate, a layer of asbestos board is laid on the steel plate, and a refractory layer with a thickness of not less than 200mm is rammed on the asbestos board. 20%-30% electrode paste or asphalt is added to the ramming material. Refractory bricks are laid on the rammed layer, and the brick joints are filled with ramming material with 20%-30% electrode paste or asphalt added.

[0009] During the operation of the iron casting machine, peat slurry is continuously sprayed into the mold to prevent the cast iron blocks from sticking to the mold. Coke dust is added to the peat to increase its refractoriness and fix its carbon content to 30%. The nozzle of the spray pipe is changed from a nozzle hole to a spray slit to effectively prevent nozzle blockage and to evenly spray the peat slurry into the mold.

[0010] Furthermore, after each casting of molten iron, the surface of the cast iron spout is cleaned of residual slag and iron, and repaired with electrode paste or asphalt ramming mix containing 20% ​​to 30%.

[0011] Furthermore, a mechanical hammer is added to rhythmically strike the cast iron block inside the mold, assisting in demolding.

[0012] Furthermore, a drain valve is added to the bottom of the shotcrete pipe to regularly remove impurities from inside the pipe.

[0013] The beneficial effects of this invention are as follows:

[0014] This invention optimizes the temperature and composition of blast furnace molten iron, ensuring its fluidity and reducing the time required to clean blockages and crusts in the cast iron runner. Adjustments to the cast iron runner construction process improve its anti-seepage capability and service life, shortening replacement and maintenance times. Improved peat refractoriness and optimized slurry pipe structure reduce slurry blockage and improve slurry application, ensuring smooth casting. The use of a mechanical hammer enhances the demolding effect of cast iron blocks and shortens the time required to clean residual iron blocks from the mold.

[0015] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Detailed Implementation

[0016] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0017] A method to improve the efficiency of molten iron casting involves selecting molten iron with stable blast furnace conditions, a molten iron temperature of 1500℃~1520℃, and a molten iron composition by mass percentage: C: 4.15%~4.3%, Si: 0.3%~0.5%; blast furnace slag basicity CaO / SiO2: 1.15~1.25; removing floating slag before casting, and adding heat-insulating agent at a rate of 0.6~1.0 kg / ton of molten iron to evenly cover the surface of the molten iron.

[0018] The construction process for the cast iron spout is as follows: the spout template is made of 10-20mm steel plate, a layer of asbestos board is laid on the steel plate, and a refractory layer with a thickness of not less than 200mm is rammed on the asbestos board. 20%-30% electrode paste or asphalt is added to the ramming material. Refractory bricks are laid on the rammed layer, and the brick joints are filled with ramming material containing 20%-30% electrode paste or asphalt. After each casting of molten iron, the surface of the cast iron spout is cleaned of residual slag and iron, and repaired with ramming material containing 20%-30% electrode paste or asphalt.

[0019] During the operation of the iron casting machine, peat slurry is continuously sprayed into the mold to prevent the cast iron blocks from sticking to the mold. Coke dust is added to the peat to increase its refractoriness, achieving a fixed carbon content of 30%. The nozzles of the spray pipe are adjusted from orifices to slits to effectively prevent nozzle clogging and ensure the peat slurry is evenly sprayed into the mold. Simultaneously, a drain valve is added to the bottom of the spray pipe to periodically remove impurities.

[0020] Add a mechanical hammer to rhythmically strike the cast iron block inside the mold, assisting in demolding.

[0021] Using the method of this invention, the casting efficiency has been increased from 1,600 tons of cast iron per day to 2,000 tons, resulting in a significant improvement in production efficiency.

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for improving the efficiency of molten iron casting, characterized in that: Select molten iron with stable blast furnace conditions, a temperature of 1500℃~1520℃, and a molten iron composition by mass percentage: C: 4.15%~4.3%, Si: 0.3%~0.5%; blast furnace slag basicity CaO / SiO2: 1.15~1.25; before casting, remove the floating slag, add heat-insulating agent at 0.6~1.0 kg / ton of molten iron, and evenly cover the surface of the molten iron; The cast iron spout construction process is as follows: the spout template is made of 10-20mm steel plate, a layer of asbestos board is laid on the steel plate, and a refractory layer with a thickness of not less than 200mm is rammed on the asbestos board. 20%-30% electrode paste or asphalt is added to the ramming material. Refractory bricks are laid on the rammed layer, and the brick joints are filled with ramming material with 20%-30% electrode paste or asphalt added. During the operation of the iron casting machine, peat slurry is continuously sprayed into the mold to prevent the cast iron blocks from sticking to the mold. Coke dust is added to the peat to increase its refractoriness and fix its carbon content to 30%. The nozzle of the spray pipe is changed from a spray hole to a spray slit to effectively prevent nozzle blockage and to evenly spray the peat slurry into the mold. After each casting of molten iron, clean the surface of the cast iron spout of the molten iron and repair it with electrode paste or asphalt ramming material mixed with 20%~30% of the material. Add a mechanical hammer to rhythmically strike the cast iron block inside the cast iron mold to assist in demolding; add a drain valve at the bottom of the shotcrete pipe to regularly remove impurities from the shotcrete pipe.