Scholarlink

<p>Nitrogen, as a deleterious element in steel, can significantly deteriorate its mechanical properties. In the context of green and low-carbon steelmaking, the electric arc furnace (EAF) short-process route has attracted considerable attention. Within this route, the ladle furnace (LF) is widely employed in the refining stage owing to its low capital investment and strong refining capability. However, due to its multitasking operations and complex process conditions, controlling nitrogen pickup in molten steel during LF refining remains challenging. In this study, numerical simulations based on FLUENT were conducted to investigate a novel nitrogen-control strategy in the LF. Furthermore, industrial experiments were performed using a 70t LF furnace at a steel plant. The CO<sub>2</sub> nozzles were installed on the furnace cover to inject CO<sub>2</sub> gas into the furnace, forming a protective layer that prevents direct contact between the molten steel surface and atmospheric N<sub>2</sub>. This approach not only enhances the cleanliness of the molten steel but also promotes the resource utilization of CO<sub>2</sub>. The effects of the nozzle polar radius and blowing angle on the distributions of velocity, temperature, and CO<sub>2</sub>/N<sub>2</sub> concentration fields inside the furnace were systematically examined in this paper. The results indicate that an increase in the nozzle polar radius leads to a gradual decrease in CO<sub>2</sub> concentration and a corresponding rise in N<sub>2</sub> concentration, while exerting minimal influence on the slag temperature. As the injection angle increases, both the volume and volume fraction of CO<sub>2</sub> initially increase and then decrease, reaching a maximum CO<sub>2</sub> concentration at a 15&#xa0;deg blowing angle. The N<sub>2</sub> concentration exhibits the opposite trend. Under this optimal condition, CO<sub>2</sub> injection exerts a pronounced effect on the temperature of both the molten steel and slag. In addition, the industrial experiment results obtained from a 70t LF furnace at a steel plant indicate that, with increasing CO<sub>2</sub> injection pressure, the nitrogen increase before and after LF treatment decreases. Compared with the conventional LF process, when the CO<sub>2</sub> injection pressure was set to 0.3&#xa0;MPa, the nitrogen pickup decreased from 10.95 to 0.14&#xa0;ppm.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Study on CO2 Top Injection for Nitrogen Control in Ladle Furnace Refining

  • 期刊论文

  • 发表日期：

    2026年3月26日

查看全文
  • Qisheng Wang,
  • Guangsheng Wei,
  • Chengjin Han,
  • Kai Liu,
  • Yabin Zhang

摘要

Nitrogen, as a deleterious element in steel, can significantly deteriorate its mechanical properties. In the context of green and low-carbon steelmaking, the electric arc furnace (EAF) short-process route has attracted considerable attention. Within this route, the ladle furnace (LF) is widely employed in the refining stage owing to its low capital investment and strong refining capability. However, due to its multitasking operations and complex process conditions, controlling nitrogen pickup in molten steel during LF refining remains challenging. In this study, numerical simulations based on FLUENT were conducted to investigate a novel nitrogen-control strategy in the LF. Furthermore, industrial experiments were performed using a 70t LF furnace at a steel plant. The CO2 nozzles were installed on the furnace cover to inject CO2 gas into the furnace, forming a protective layer that prevents direct contact between the molten steel surface and atmospheric N2. This approach not only enhances the cleanliness of the molten steel but also promotes the resource utilization of CO2. The effects of the nozzle polar radius and blowing angle on the distributions of velocity, temperature, and CO2/N2 concentration fields inside the furnace were systematically examined in this paper. The results indicate that an increase in the nozzle polar radius leads to a gradual decrease in CO2 concentration and a corresponding rise in N2 concentration, while exerting minimal influence on the slag temperature. As the injection angle increases, both the volume and volume fraction of CO2 initially increase and then decrease, reaching a maximum CO2 concentration at a 15 deg blowing angle. The N2 concentration exhibits the opposite trend. Under this optimal condition, CO2 injection exerts a pronounced effect on the temperature of both the molten steel and slag. In addition, the industrial experiment results obtained from a 70t LF furnace at a steel plant indicate that, with increasing CO2 injection pressure, the nitrogen increase before and after LF treatment decreases. Compared with the conventional LF process, when the CO2 injection pressure was set to 0.3 MPa, the nitrogen pickup decreased from 10.95 to 0.14 ppm.