Low Carbon Operation of Super-Large Blast Furnaces in China

Abstract

There are 19 super-large blast furnaces more than 4 000 m 3 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 SiO 2 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.KEY WORDS: super-large blast furnace; low carbon operation; fuel rate; gas utilization efficiency; economic coal injection; blast furnace visualization technology.

Analysis of Blast Furnace Hearth Sidewall Erosion and Protective Layer Formation

“…Ke-Xin JIAO, 1,3) Jian-Liang ZHANG, 1,2) Zheng-Jian LIU, 1,2) * Chun-Lin CHEN 3) and Yan-Xiang LIU The blast furnace campaign life is largely determined by the damage to the hearth area. Bricks and skulls in the hearth were sampled and investigated after the blowing-out of one commercial blast furnace.…”

“…1,2) Procedures have been pursued and BF campaign lives have been steadily increasing. 3,4) Many studies on the relationship between inner hearth condition and BF operating conditions, such as heat load, molten iron flow, the lower boundary level and permeability distribution of deadman in hearth have been carried out by using numerical simulation method.…”

Economical and Efficient Protection for Blast Furnace Hearth

“…Yong DENG, 1,2) Jian-liang ZHANG 1,2) and Ke-xin JIAO 1,2) * In order to clarify the erosion mechanism of carbon brick and realize the economical and efficient protection for blast furnace hearth at the end of the service. The damaged carbon bricks were sampled from a commercial blast furnace, the microstructure of the damaged carbon bricks was analyzed through SEM and EDS.…”

“…1,2) The burn out of hearth occurred from small BF (100 m 3 ) to large BF (4 747 m 3 ), hearth had always been the limiting area for long campaign life of BF. 3) However, the erosion mechanism of carbon brick was not clear although many dissection investigations were carried out in the past.…”

Operation Characteristic of Super-Large Blast Furnace Slag in China

“…1 showing the slag compositions and hot metal temperature (T HM ) of the Chinese super-large BFs. 1,[18][19][20] C/S (CaO/SiO 2 ) of slags is controlled within 1.12 to 1.24 except No.10 BF, which is 1.08 and lower than others. Mg/Al ratio ranges from 0.45 to 0.7.…”