Recently, the "Development and Application of High-iron and Low-silicon Alkaline Pellets" project, completed by a research team composed of researchers from the Shougang Technology Research Institute and Jingtang Company won the first prize awarded by Shougang Science and Technology in 2019. This project has provided important support for the “Key Technologies for Greening of Steel Processes” key research and development plan, which is a part of China’s national Thirteenth Five-Year Plan. Through this project, Shougang is able to play a leading role in realizing energy conservation, environmental protection and green development goals for steel companies.

Pellets are one of the main charging materials in blast furnace ironmaking. In the ironmaking process, increasing the proportion of high-quality pellets into the furnace can help improve the technical and economic indicators of the blast furnace, as well as reduce pollutant emissions and energy consumption in the process. Given the strict energy conservation and environmental protection requirements now in place, as well as the demand among iron and steel enterprises to reduce costs, iron and steel companies must look to improve the quality and proportion of the pellets they are using in their blast furnaces, in order to achieve sustainable development.

In order to promote the low-carbon and green development of the steel industry, and reach the goal of achieving a 50%+ proportion of pellets used in the three 5,500-cubic-meter blast furnaces at Shougang Jingtang Company, the Technical Research Institute and former iron professionals from Jingtang Company formed a research team at the end of 2015. They explored new ideas from across the world, whilst also taking practical concerns into account, eventually putting forward the innovation of using slaked lime to produce ultra-low-silicon alkaline pellets, greatly reducing the amount of blast furnace slag as well as fuel consumption thus realizing high-efficiency and low-carbon ironmaking. After more than 3 years of hard work, they have overcome various problems to finally develop high-quality high-iron and low-silicon alkaline pellets, achieving stable smelting of more than 55% pellets in 3 large blast furnaces.

According to Dr. Qing Gele of the Technical Research Institute, during the project development process, the team were faced with many difficulties, including the difficulty of controlling the reduction expansion rate of ultra-low silicon pellets, the clogging of the grate and the air distribution plate of the belt roaster, and electric dust removal failures. Faced with these difficulties and pressures, the project team did not waver. They conducted repeated experimentation and analysis, holding frequent team meetings to discuss the causes of various problems, and formulate solutions. This hard work paid off. After 6 industrial trials, the project team successfully developed high-quality low-silicon alkaline pellets whose comprehensive indicators reached international advanced levels. At the same time, they developed a smelting system for super-large blast furnaces with high proportion of pellets, which achieved stable smelting with pellets exceeding 55%. The amount of blast furnace slag is reduced to less than 215kg/t, and the fuel ratio is reduced to less than 480kg/t. As a result, Jingtang Company had reduced carbon dioxide emissions by more than 700,000 tons and reduced pollutants such as nitrogen oxides, sulfur dioxide, and carbon monoxide by more than 900,000 tons annually. 

During the project development process, the research teamed applied for 7 national patents, including 5 invention patents. Aside from this, they also published 9 papers in domestic and foreign journals and important academic conferences.

In recent years, in order to construct high-efficiency, low-carbon and green ironmaking platforms, Jingtang Company and the Technology Research Institute have continuously worked to improve the quality of raw fuels, developed global group smelting technology, and boldly tested and produced various types of pellets, such as "low-silicon magnesium" "low-silicon titanium and magnesium" and "high titanium", meeting the various needs of different blast furnaces and improving the technical and economic indicators of blast furnaces. At the same time, they also formulated national standards, including the Test and Calculation Method for Thermal Balance of Belt Roasters, helping to guide Chinese pellet technology and increase the proportion of pellets used in blast furnaces.