Problems in blast furnace ironmaking

 　　one

　　We should pay attention to the strength of sintered ore and more importantly, its metallurgical properties. As the main iron-containing raw material for blast furnaces in China, sintering ore not only includes macroscopic physical and chemical properties such as strength, particle size, and grade, but also needs to pay attention to the high-temperature physical and chemical properties exhibited by sintering ore during the smelting process of blast furnaces, such as the metallurgical properties of sintering ore, such as reducibility, softening and melting properties.

　　two

　　To comprehensively evaluate and assess the performance of block ore, especially its metallurgical performance. At present, the main problems exposed during the use of block ore include: high powder content, poor reducibility and high-temperature softening melting performance, unrepresentative hot cracking performance and detection, and excessive harmful elements and content. These issues have an impact on the use of block ore and the blast furnace smelting process, and it is necessary to further improve the performance evaluation system of block ore.

　　two

　　The price of raw materials and fuels is distorted, and more attention should be paid to coke quality. The rising prices of coal and coke have led some enterprises to sacrifice coke quality in order to reduce costs, resulting in a decline in ironmaking technical and economic indicators. This phenomenon is also sufficient to demonstrate the importance of coke quality for blast furnace smelting.

　　three

　　In terms of efficient and long-lasting blast furnaces. The longevity technology of blast furnace is a systematic project that requires comprehensive technical measures. The longevity development of blast furnaces in China is very uneven, with an average lifespan of only 5-10 years, and there is still a significant gap compared to foreign blast furnaces. In recent years, there has been a significant increase in cases of abnormal increase in the temperature of the side walls of blast furnace hearth and even burning through of the hearth, indicating that there are still significant problems with the longevity of blast furnace hearth in China. It is worth noting that since 2010, with the strengthening of blast furnace smelting, some steel enterprises have encountered the problem of copper cooling wall damage, which is worth further research and improvement.

　　four

　　In terms of increasing the temperature of the hot air. Improving wind temperature can effectively reduce coke and fuel ratios, reduce production costs, and is a key technology for sustainable development and low-carbon smelting in the current steel industry. In 2016, 36 steel association member units experienced a decrease in hot air temperature, while 27 companies experienced an increase in hot air temperature. At present, there are still 5 enterprises with hot air temperatures below 1100 ℃, and there is still a long way to go from the ideal high air temperature of 1280 ± 20 ℃, and it is necessary to continue promoting high air temperature technology.