Analysis of high and stable production of blast furnace

Shougang operates five blast furnaces, with the first four undergoing significant modifications between 1991 and 1994. The total capacity of these furnaces is 9,934 m³. Following the expansion, the workload for tapping and slag removal in front of the furnace increased significantly, leading to challenges such as frequent furnace surges, difficulty in maintaining the iron mouth, and high labor intensity for workers. Additionally, the consumption of refractory materials and auxiliary supplies was high, which not only hindered normal production but also raised costs and caused environmental pollution. As furnace operations advanced and material quality improved, the demand for more efficient and stable performance became higher. In response, Shougang’s steelworkers and technicians conducted extensive research and experiments, gradually overcoming production limitations. This led to a reduction in worker workload, from nearly 20 people to just 10 today, and a drop in refractory material consumption from about 10 yuan per ton of iron to 4 yuan. Today, the work in front of the furnace meets the requirements for high and stable production. In terms of technical progress, the maintenance of the iron mouth has seen major improvements. Hydraulic mud guns and opening machines were introduced, enhancing the efficiency of iron and slag removal. However, some furnaces faced difficulties in maintaining the iron sluice due to lack of slag sump usage. Through continuous efforts, the pass rate of the iron mouth reached over 99.8%, making it a key factor in extending the life of the blast furnace. The iron mouth, being a weak point in the hearth, directly affects the furnace's longevity. For example, the utilization coefficient of the 2000-3000 m³ vertical blast furnace exceeds 320 kg/t, with an optimal number of tap times around 13. Shougang developed different types of gun mud tailored to each furnace, addressing issues like iron mouth erosion and mud flow. After 1995, adjustments in raw material composition and particle size improved the thermal conductivity and sintering performance of the mud, resulting in better maintenance and fewer incidents of decompression or furnace enthalpy loss. The use of new castable mud sleeves reduced labor intensity and eliminated the need for repeated mud application. Iron-injection technology was also introduced to manage excessive gas at the iron mouth, improving safety. By using resin press-in materials, the problem of gas fire was effectively addressed through a structured process involving cleaning, sealing, pressing, and curing. In the slag and iron ditch area, the transition from ramming materials to castables significantly extended service life and reduced costs. Continuous improvements in casting techniques, including proper mixing, vibration, and baking, ensured high-quality results. The main trench reconstruction and hot spray repair methods further enhanced durability and reduced maintenance frequency. The development of the residual iron opening machine shortened the opening time, improved safety, and reduced labor intensity. Special arrangements for slag and iron disposal, including dry slag pots and coke-filled slag traps, ensured efficient waste management during furnace operations. Environmental protection measures, such as installing dust collectors and upgrading filtration systems, helped control dust emissions and improve the working environment. These efforts have collectively contributed to safer, more efficient, and sustainable operations in front of the blast furnaces. In conclusion, over the past decade, Shougang has made significant progress in maintaining the iron mouth, managing the slag and iron ditches, and improving the working environment. Continued improvements in equipment and materials will further enhance efficiency and sustainability.

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