Analysis of high and stable production of blast furnace

Shougang has five blast furnaces, with the first four undergoing significant modifications between 1991 and 1994. The total furnace capacity now stands at 9,934 m³. After the expansion, the workload for tapping and slag removal in front of the furnace increased significantly. This led to challenges such as frequent furnace surges, difficulty in maintaining the iron mouth, and high labor intensity among workers. Additionally, the consumption of refractory materials and auxiliary supplies was high, which not only limited normal production but also raised costs and caused environmental pollution. As furnace operation and material quality improved, the demands on the blast furnace became higher. In response to these issues, steel workers and technicians conducted continuous research and experiments, gradually solving the problems that had previously hindered production. Over time, the workload decreased, with the number of workers in front of the furnace dropping from nearly 20 to around 10 today. Refractory material consumption per ton of iron has also reduced from about ¥10 to ¥4, and current operations now meet the requirements for high and stable production. In the front of the first blast furnace, technical progress has been made in several areas. One key area is the maintenance of the iron mouth. With the overhaul of Shougang's blast furnaces, hydraulic mud guns and opening machines were introduced, improving the efficiency of iron and slag removal. However, some blast furnaces lacked proper slag openings, making it difficult to maintain the iron mouth. Recent improvements have led to an iron mouth pass rate exceeding 99.8%, with the quality of the iron mouth becoming a critical factor in extending the life of the blast furnace. Different types of gun mud have been used based on the characteristics of each furnace. For example, after the No. 1 blast furnace was opened in 1994, it was found that the original waterless mud was insufficient for its needs. Adjustments were made to the raw material composition, reducing particle size and improving thermal conductivity, leading to better sintering performance. This resulted in a reduction in the number of tap times, from over 16 to 10–12 per day. Another advancement was the use of pouring mud sleeves, replacing traditional water-based mud. These new sleeves significantly reduced labor intensity and improved the success rate of mud casting to 100%. Iron-injection technology was also introduced to address gas issues at the iron mouth, using resin press-in materials to stabilize the area and improve safety. Regarding the slag and iron ditches, Shougang shifted from ramming materials to castables, which greatly improved their service life. The cost of refractory materials has dropped from ¥10 to ¥4 per ton of iron. Casting techniques were refined, with attention to mixing, vibration, and baking processes to ensure optimal performance. Hot spray technology was also adopted to repair damaged areas quickly, reducing maintenance frequency and extending the life of the main ditch. The dismantling of the iron mouth machine was another improvement, reducing the time required to open the iron mouth from 30 minutes to just 3–4 minutes. This not only improved efficiency but also reduced risks and labor intensity. Environmental protection measures, including dust collection systems and improved ventilation, have also been implemented to enhance the working environment and reduce pollution. Overall, Shougang’s efforts in the front of the blast furnace have significantly improved operational efficiency, reduced costs, and enhanced worker safety and environmental sustainability. Future improvements will focus on further optimizing equipment and materials to achieve even higher productivity and longer furnace life.

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