2015 Volume 55 Issue 6 Pages 1146-1156
There are 19 super-large blast furnaces more than 4000 m3 running in China currently, and significant progresses of low carbon operation were obtained in recent years. In this paper, low carbon operation technologies of Chinese super-large blast furnaces were illustrated in the two aspects of raw materials preparation and blast furnace operation. Firstly in terms of raw materials preparation, low carbon operation technologies include producing low SiO2 content and high reducibility sinter to reduce slag volume and improve sinter metallurgical properties; optimizing coal blending structure for coking to guarantee coke quality; implementing blending yard technology to stabilize blast furnace operation; controlling harmful elements load to reduce their damage to coke; adopting screening technology to reduce dust amount; recycling small size sinter, nut coke and CDQ dust to improve ironmaking energy efficiency. Secondly in terms of blast furnace operation, low carbon operation technologies include improving gas utilization efficiency by upper adjustment and lower adjustment, the upper adjustment including charging mode, batch weight and stock line level, lower adjustment including the control of blast volume and blast kinetic energy; implementing comprehensive blast technology of high blast temperature, dehumidified blast and high top pressure, promoting economic coal injection concept; conducting low silicon smelting, but should pay attention to its impact on campaign life of blast furnace; controlling thermal load to reduce heat loss, emphasizing middle-part management of blast furnace; development and application of blast furnace visualization technology to guarantee long-term smooth operation of blast furnace.