Abstract: This paper elaborates on the main technological improvements of Baosteel's COREX 3000 and introduces the R&D work carried out to enhance the competitiveness of COREX 3000 technology. The design of COREX 3000 fully draws on the lessons learned from the production of C1000 and C2000 furnaces and the successful experience of blast furnaces. Significant improvements have been made to the furnace body, refractory materials, furnace cooling system, and charging device, increasing the designed capacity from 800,000 tons for C2000 to 1.5 million tons. Combining the characteristics of the Luojing project itself, Baosteel is conducting technological research and development on the effective utilization of COREX gas, pulverized ore, and pulverized coal to optimize the entire process flow, striving for significant improvements in technical and economic indicators, operating rate, and furnace life compared to C2000. Keywords: Molten reduction, COREX, Pulverized coal, Pulverized ore 1 Introduction According to the site selection requirements of the 2010 Shanghai World Expo, Baosteel Group decided to relocate Shanghai Pudong Iron & Steel Co., Ltd. from under the Lupu Bridge to the Luojing area of ​​Baoshan District. The relocation project of Pudong Steel to Luojing adopted the world's most mature COREX molten reduction ironmaking process to replace Pudong Steel's original outdated molten iron steelmaking process and solve the problem of hot iron supply. The residual gas output from molten reduction, besides being used as fuel for the steel plant itself, will be recycled in stages. Being the first to adopt COREX 3000 (hereinafter referred to as C3000) ironmaking equipment is the starting point and opportunity for Baosteel's non-blast furnace ironmaking technology innovation. Based on the digestion and absorption of COREX technology, Baosteel will further research and develop new non-blast furnace ironmaking technologies with independent intellectual property rights. Baosteel will build Luojing into a research and development base for new non-blast furnace ironmaking processes. This article focuses on the main technological improvements of Baosteel's Luojing C3000. 2 Baosteel Luojing C3000 Process Flow The Luojing project is located next to the Luojing coal wharf on the Yangtze River at the northernmost tip of Shanghai, covering an area of ​​approximately 3.2 square kilometers. The entire project is constructed in two phases. The first phase has a production scale of 2 million tons of billets, with special medium and heavy plates as the main product. The first phase involves the construction of one 33,000-ton furnace with a reserved interface for future FINEX development. This includes coal drying facilities, pulverized coal utilization, ore/coal bins and feeding facilities, the C3000 furnace body, a gas cleaning system, a slag and iron system, a casting machine, a water treatment system, etc. The gas will be used as fuel for the plant's own operations and for CCPP generator sets. Gas differential pressure power generation (TRT) and gas desulfurization systems will also be constructed. The second phase will have a production capacity of 3.35 million tons of billets, with the construction of another COREX furnace and one DR vertical shaft furnace. The Luojing project's technology and equipment will be designed to world-class standards, adhering to the principles of advancement, completeness, forward-thinking, and economy. The goal is to achieve advanced technology, reliable equipment, first-class products, a beautiful environment, and reasonable investment, ensuring the Luojing project is completed at high speed, with high quality and high efficiency. COREX is a molten reduction ironmaking process developed by Voestalpine and Kof GmbH of Germany. It is currently the only molten reduction ironmaking process to have achieved industrialized production. Its principle is equivalent to dividing the blast furnace into two sections from the softening zone, allowing direct production using natural lump ore, pellets, a small amount of fines, non-coking coal, and a small amount of coke. The COREX molten reduction ironmaking process is shown in Figure 1. To date, five COREX units have been put into production (one C1000 and four C2000). Except for the first C1000 unit at Isco Steel's Pretoria plant in South Africa, which is now out of production, and the C2000 unit at POSCO Steel in South Korea, which has been converted to FINEX, the other three C2000 units are in normal production. Baosteel Group's Pudong Steel Company is currently building the world's first C3000 type COREX, with a designed annual output of 1.5 million tons. The main design parameters of Baosteel's Luojing C3000 are shown in Table 1. The pre-reduction vertical shaft furnace of the Luojing C3000 (total height 29m) Eight screw conveyors are arranged horizontally along the circumference at the bottom of the furnace (12m high, 8m inner diameter of the reduction section), continuously feeding material to the molten gasifier while it is hot. Each screw conveyor consists of a DRI screw conveyor, a DRI feed pipe, a DRI feed pipe compensator, and a DRI distributor. Four hot cyclone dust collectors are installed in the molten gasifier's output gas pipeline system. The high-temperature gas pipeline leading from the molten gasifier and the inner wall of the dust collectors are lined with refractory material. Four sets of hot cyclone dust collector ash return devices are installed below the hot cyclone dust collectors. The powder collected by the hot cyclone dust collectors is returned to the molten gasifier through four dust injection systems via four combustion ports on the upper dome of the molten gasifier. The C3000 molten gasifier (33m high, 9m hearth inner diameter) has 28 oxygen tuyeres, each consisting of a small tuyere sleeve, a large tuyere sleeve, and an oxygen lance. Six oxygen burners are located in the dome space above the semi-coke fixed bed to improve and adjust the thermal condition of the molten gasifier dome. The C3000 molten gasifier has two tapholes with an angle of 180° between them. Slag is produced using the new Imba process granulation, and after dewatering, it is transported by truck. 3. Major Design Improvements of Baosteel Luojing C3000 3.1 The design improvements of the C3000 molten gasifier by Voestalpine (VOT) drew on successful blast furnace experience. For example, it incorporated the longevity lessons learned from large oxygen-enriched pulverized coal injection blast furnaces, increasing the belly angle to 220 degrees (a reduction according to blast furnace calculations) to prevent cooling wall erosion. Two sections of copper cooling walls were used above the tuyeres, increasing the volume of the semi-coke fixed bed. The length of the taphole and the depth of the dead iron layer were increased to reduce the scouring and erosion of the hearth by molten iron. Other design improvements were also made to the C3000 gasifier, such as reducing the free space in the dome above the semi-coke fixed bed compared to the C2000, increasing the outlet angle of the gas pipeline, optimizing the dust recirculation system, increasing the number of oxygen burners in the dust burners in the dome free space from four to six (C2000), and increasing the height of the semi-coke bed above the tuyeres from 7m (C2000) to 10m (C3000), etc. 3.2 Improved Design of the Reduction Shaft Furnace: To accommodate the volume expansion of the charge during the reduction process, the C3000's furnace angle was adjusted during the design process to facilitate the smooth flow of the charge. The C3000 increased the diameter of the gas casing pipe and the height of the section below the casing pipe, improved the refractory material design, and increased the pressure differential at the bottom of the furnace. This prevented or reduced the direct intrusion of gas from the gasifier into the reduction shaft furnace through the sponge iron feed pipe, which could lead to excessively high local charge temperatures and agglomeration. Simultaneously, to reduce clogging caused by sponge iron agglomeration, the C3000's design also adjusted the length and diameter of the sponge iron screw conveyor and the diameter of the sponge iron feed pipe. 3.3 Improvement of Furnace Cooling System Design Based on the production experience of C2000, in order to improve the furnace cooling of the semi-coke fixed bed section below the dust burner of the molten gasifier, C3000 has made design improvements to the cooling system of the molten gasifier. The number of cooling walls has been increased from 9 to 10. At the same time, the material selection of the cooling walls has also been improved. Two sections of copper cooling walls have been used in the furnace belly above the tuyeres to improve the cooling effect of the furnace body and achieve effective protection of the furnace body. 3.4 Improvement of Charging System Design (1) Improvement of Charging System Design of Reduction Vertical Furnace. In order to solve the shortcomings of particle size segregation, density segregation and uneven material distribution in the reduction vertical furnace, the charging method of the vertical furnace has been changed from the original spider leg charging method to the Gimbal type dynamic charging method, which can effectively improve the gas distribution in the vertical furnace, improve the gas utilization rate and the quality of sponge iron. (2) Design improvement of the sponge iron feeder in the molten gasifier. The C3000 uses an adjustable baffle plate on the sponge iron feeder (see Figure 2). By adjusting the angle of the baffle plate, the distribution of sponge iron is controlled, so that the sponge iron is distributed as evenly as possible in the semi-coke bed material surface area, improving the process conditions for the final reduction of sponge iron in the gasifier. (3) Design improvement of the coal feeding system in the molten gasifier. The C3000 molten gasifier adds a Gimbal-type annular rotating dynamic feeder, which can effectively control the coal feeding pattern and range according to the process requirements (see Figure 3), avoiding coal from falling into the center of the material surface, so that the coal is distributed as evenly as possible in a large area of ​​the semi-coke bed surface, improving the process conditions for coal gasification and coking in the furnace, and making the process more stable. 3.5 Improvements in Refractory Material Design Based on the design and production experience of (22000), many improvements were made to the design of refractory materials for the gasifier and reduction shaft furnace of C3000. Among them, the design of the refractory material for the gas casing of the shaft furnace was improved, which improved the structural stability of the refractory material and facilitated the distribution of gas in the shaft furnace. At the same time, the artificial dead material column of the shaft furnace was integrated into the design, which improved the smooth flow of the furnace charge and helped reduce the blockage of the furnace charge. Combining the experience of Baosteel blast furnace, the refractory material of (23000) was optimized, and many improvements were made in the configuration and design of the hearth refractory material. The service life of the first generation furnace of C3000 can reach 10-15 years. 3.6 Other Design Improvements Based on the C2000, the C3000 improved the structure of the dust return blowing system, changing it from the original "CLOSE" mode to "OPEN" mode. The structure of the T-type mixer was also improved, and a coarse particle filter screen was added, effectively reducing clogging in the dust return blowing system. Simultaneously, the C3000 also improved the design of the gas pipeline, effectively reducing the content of coarse dust particles in the gas entering the shaft furnace and improving the permeability of the reduction shaft furnace charge. 4. Baosteel Luojing (23000) Main Research Topics From the commissioning of the first C1000 type COREX in 1989 to the present, the development time of COREX is only 17 years, which is very short compared to the 600-year development history of blast furnaces. There are still many areas that need improvement in terms of process and technology. Baosteel Group is currently building a COREX... This project is not only China's first COREX facility but also the world's first C3000-type COREX. Combining the unique characteristics of the Luojing project, Baosteel is conducting research and design work on numerous technical development topics related to C3000 production. These topics include: coal and ore blending technology to meet C3000 production requirements; effective utilization technology for 5mm iron ore undersize powder and 5mm coal powder entering the plant; assimilation and innovation of C3000 ironmaking operation technology; safety production technologies related to the large-scale use of oxygen and coal powder in C3000; COREX gas desulfurization technology for CCPP power generation; process technology for high-efficiency cascade COREX gas for DRI or clean energy production; life cycle assessment research on a product of the COREX process; and process technology for the recycling of COREX solid waste. The purpose of this research and development is to improve the stability and economy of COREX resource utilization, and to conduct secondary innovation based on the assimilation and introduction of foreign technologies, optimizing the entire COREX ironmaking process to achieve better technical and economic indicators.