Application of premelted reducing agent in electric arc furnace

A steel plant has two 90t eccentric bottom arc furnaces, which quickly smelt the bottom steel, and the reducing agent uses carbon powder and aluminum powder.

1. Improvement and update of the reduction process

The electric arc furnace is changed to the eccentric bottom tapping steel, and the reduction process is developed from the reduction mechanism of the “third-stage smelting” to the smelting mechanism of rapid melting and rapid reduction, and the smelting process becomes simpler and faster. The reducing agent is mostly forced to reduce by a single reducing agent such as carbon powder or aluminum powder. Since the slag condition is difficult to control during the smelting process, the reduction effect of adding the reducing agent is not ideal. Therefore, in order to improve the reduction effect of various reducing agents and the utilization rate of reducing agents, it is necessary to further improve the reduction mechanism, and use a composite reducing agent such as silicon manganese alloy, silicon calcium alloy, etc. to enhance the reduction effect, and more importantly, The slagging and reduction are carried out at the same time, the utilization rate of the reducing agent is increased, and the pre-melting type reducing agent is introduced, thereby achieving the perfect combination of the smelting process.

2. Composition of pre-melted reducing agent

The composition of the premelted reducing agent is as follows: C _a O45% to 55%, Al ₂ O ₃ 15% to 25%, Al powder 8% to 10%, Si powder 10% to 20%, and C _a F 5% to 8%. The rest of the impurities.

The pre-melting type reducing agent is a combination of an aluminum-calcium-based slag agent, a pre-flux agent and a plurality of composite reducing agents, which has both a rapid slagging action and a composite reducing oxide function, and the pre-melting type slag material The composite reducing agent is effectively dispersed, so that the utilization rate of the reducing agent is greatly improved, and the reduction effect is better.

3. Application of pre-melting reducing agent

Premelted reducing agent has a very unique metallurgical theoretical perspective, and has a wide range of operability, very suitable for use in electric arc furnaces; our factory introduced in 2009, the effect is very good, now the two electric furnace production steel are all using this product reduction.

The attached table is the statistical data for production and application on a 90t electric furnace in a steel mill.

4. Conclusion

In summary, after using the pre-melting type reducing agent, the amount of Al and Si added is obviously reduced, and the reduction effect of the original process can be achieved by saving about half of the precious metal. The test has achieved satisfactory results, and the saving is very considerable. of.

About the author: Feng Zhongliang, Gong Yi Zhenhua Furnace Co., Ltd.

Yuan Zhiliang, Harbin Electric Machinery Co., Ltd., senior engineer, engaged in electric arc furnace, LF, VOD refining process and furnace refractory application and research.