Blast furnace outlet is one of the most important parts of the blast furnace, is the blast furnace to discharge hot metal and slag channels, generally set to 1-4. Whether the iron outlet is smooth or not and the size of iron flux are important factors affecting the operation of the blast furnace. Blast furnace blast mud is the plastic refractory material used to seal the iron outlet, and it is also the daily consumption resistant material with the largest cost proportion in the steelmaking process, reaching 80% of the total cost of consumption resistant material. Therefore, the study of blast furnace mud is very important, which is directly related to the life of blast furnace and the cost of iron and steel making.
FIG. 1 Schematic diagram of blast furnace outlet
In recent years, the upsizing of blast furnaces and the application of enhanced smelting technology have led to the prolongation of iron production time and the increase of iron production times, which makes the requirements for iron outlet and working environment more demanding, and also puts forward higher requirements for gun mud. By 2019, China has reached 22 large blast furnaces above 4000m³, the maximum volume of blast furnaces has reached 5800m³, there are 4 iron outlets, and the average number of iron production is 10 to 13 times per day. For example, the two 4063m³ blast furnaces of Baosteel have a maximum daily iron capacity of 10000t, a slag discharge capacity of 3200t, an iron discharge speed of 5.8-7.5t ·min⁻¹, and an iron discharge time of more than 120min. The plasticity, refractoriness, corrosion resistance of iron slag, sintering strength and opening performance of mortar are all required and challenged. The performance of the mud is related to the production and operation of the blast furnace. If the quality of the mud is not good, there will be various problems, such as broken iron, wet iron, shallow iron, etc., and even cause personal safety accidents. On the contrary, the quality of blast mud is good, the aperture is stable, the iron discharge is uniform, and the iron mouth maintains a certain depth, which can optimize the production of blast furnace and reduce the consumption of refractory materials.
In this paper, the types of cannon mud and the characteristics and applications of different kinds of cannon mud are introduced, and the latest research progress of cannon mud is summarized from three aspects: raw material (chemical composition, particle composition, water content), additives and bonding agents, and the research ideas and development direction of cannon mud are prospected.
FIG. 2 Schematic diagram of blast furnace outlet
The schematic diagram of the vacuum vibration pouring device is shown in Figure 1. Place the mixed slurry (with 8% water (w)) in the funnel of the device, vacuum to -0.09MPa, hold the pressure for 30min, open the shaking table to make the vibration frequency 60Hz, vibrate for 1min after the slurry has completely flowed into the mold, and put air into the device after stopping vibration. Press molding process: Put the blank (moisture content 8%(w)) into the mold of the brick press, and maintain the pressure 90s under 200MPa pressure. After forming, the billets were dried at 100℃ for 72h and sintered at 1400℃ for 8h.