China steel products development direction

1. Change the production process route of bar and wire

At present, the proportion of rebar and wire rod in China's steel output is 34.7% and 19.9%, as shown in Table 1. If 50% of the steel output is replaced by EAF, 598 million tons of carbon dioxide emissions can be reduced. Graphite electrode has excellent conductivity and thermal conductivity, and is suitable for EAF/LF steelmaking. The main products of EAF short process steel plants in the United States and Germany are also plain carbon steel bars and wires. Compared with the long process of blast furnace and converter for producing plain carbon steel, the process of EAF is simple. Baosteel put forward the concept of micro steel manufacturing park, which is also the construction of hundreds of micro EAF steel plants. Through these environment-friendly EAF steel plants, plain carbon long products are provided for urban development.

Table 1 Classification of Iron and Steel Products in China

2. Price control of scrap steel

The State Council Development and Reform Commission encourages enterprises to set up large steel scrap recycling, processing and distribution centers through policies to solve the quality and quantity of scrap steel raw materials; In addition, through the standardized management of scrap steel enterprises and the establishment of scrap steel standards, the stable quality of China's scrap resources can be ensured. Scrap steel enterprises and some iron and steel enterprises are also building scrap treatment workshops to reduce scrap purchase costs. The transformation of EAF steelmaking process is not only a link, but also a systematic project with strategic height, which is related to the entire upstream and downstream industrial chain. After stabilizing the supply of scrap steel, the scrap steel price is generally lower than molten iron price, so that China's EAF steelmaking process can be competitive.  

3. New technology of plain carbon steel EAF steelmaking

At present, China's plain carbon steel EAF process level is still a certain distance from the world level. We need to learn to master new EAF smelting technology:

(1) Horizontal charging EAF plays a leading role: under the condition that horizontal charging can realize continuous electricity, scrap can be added to the EAF, which shortens the smelting cycle and improves the production efficiency.

(2) Large proportion of reserved steel operation:

The research shows that when the steel reserve is less than 10%, the smelting time is 58.5 min, and the power consumption is 412kW h/t; The amount of remaining steel is 45.7%, and the power consumption of smelting time is 384kW h/t, 51.5min. In the case of EBT eccentric bottom tapping and steel retaining operation, the high proportion of steel retaining operation can increase the productivity by 12% and reduce the power consumption of 28Kwh per ton of steel.

(3) High power EAF:

Newly built electric furnaces generally adopt high power transformers, with a power of more than 800kVA per ton of steel. According to statistics, after 2000, there were 25 steel plants in North America newly built or transformed to produce plain steel EAFs. The power per ton of steel of 21 EAFs was more than 800kVA, and the oxygen consumption was more than 30m³ per ton of steel.

(4) All scrap EAF increases the oxygen consumption.

(5) AC EAF is the mainstream equipment in plain carbon steel EAF steelmaking.

4. Conclusion

EAF steelmaking is an environment-friendly industrial technology to achieve circular economy. Compared with the long process steelmaking process of blast furnace and converter, it greatly reduces carbon dioxide greenhouse gas emissions. At present, China gives support from the industrial policy. After 2020, the social waste steel will accumulate more than 300 million tons every year, laying the foundation for the development of EAF steelmaking, and the competitiveness of EAF steel will be enhanced.

The stage of China's economic development, the accumulation of iron and steel resources, and the development process of EAF steelmaking in developed countries can judge that China's EAFs will enter a rapid development stage after 2020. The policy of the National Development and Reform Commission of China points out that some blast furnace and converter processes have been transformed into EAF steelmaking processes to promote the overall energy conservation and environmental protection level of the industry. At present, Baosteel and private iron and steel enterprises in Fujian, Guangdong and Sichuan plan to build plain carbon steel EAFs.  

In the process of increasing the proportion of EAF steel, the guarantee of scrap steel quality and quantity, the adoption of new EAF steel technology, and the role of China Engineering Corporation in EAF projects need to be emphasized.  

It can be predicted that after 2020, the EAF steel proportion will increase, and the EAF steelmaking process will play an important role in China's economic development towards high quality. Welcome to contact us for daily EAF industry news.