Steel Plants with COREX Process in Operation: A Quick Review

This article presents a quick review about some of the steel plants with COREX process in operation especially, as how these COREX plants were started and subsequent developments and changes brought in those COREX plants. Because of its techno-commercial and ecological advantages the COREX Process, besides the FINEX technology, is the only industrially accepted alternative to the blast furnace route for the production of hot metal. Current COREX pre-projects also indicate an existing demand for the “by-product” COREX gas for power generation and for the production of DRI. You may also like to read: COREX Process ofIron Making - its Merits and Demerits

Steel Plants with COREX Process in Operation  

ArcelorMittal Steel, Saldanha Works, South Africa   

An Integrated Compact Mill (ICM), based on a COREX C-2000 plant and the Midrex DR plant was started up in mid 1999 at ArcelorMittal Steel South Africa (Saldanha Steel), situated near the west coast of South Africa. It is operated with mainly indigenous iron ores comprising SISHEN lump ore (80 - 100%), CVRD pellets (0 - 20%) and indigenous coal from the VAN DIJKSDRIFT and GROOTELUK coal districts. COREX gas from the plant is used for the production of DRI in the adjacent DR plant using a MIDREX shaft furnace and a LINDE Vacuum Pressure swing Absorption plant (VPSA). Both the hot metal from COREX plant and direct reduced iron (DRI) are processed to high quality steel in a twin-shell EAF, followed by thin slab casting and direct rolling in the hot strip mill to produce high quality hot rolled coils (HRC). It is only steel mill in the world to have successfully combined the Corex / Midrex process into a continuous chain - replacing the need for coke ovens and blast furnaces, and making the plant a world leader in emission control and environmental management.

Plant highlights / developments:

• The COREX plant operation is based on approx. 80% local lump ore charging.
• Typical annual production for the COREX / MIDREX DR plant combination is 700,000 t/a HM and 700,000 t/a DRI.
• Compared to other ArcelorMittal steel plants, this steel works is within the plants with the lowest production cost.

JSW Steel, Toranagallu Works, Bellary, Karnataka, India

Considering the importance of environment protection, resource conservation and sustainable development in India, JSW Steel (formerly, Jindal Vijaynagar Steel Ltd) opted for COREX technology (COREX + BOF route) for its integrated iron making project. JSW Steel (India) has two COREX C-2000 and one combined COREX gas based MIDREXTM DR plant. Start-up of COREX C-2000 plant Module 01 and 02 took place in 1999 and in 2001 respectively. This process allowed greater flexibility of operation as well as use of non-coking coals as a primary fuel and raw materials of less stringent quality. Some of the special features of COREX hot metal are high temperature (1480 - 1510^OC), low sulphur, low nitrogen and least amount of impurities. This has proved to be more eco-friendly as compared to the conventional blast furnace route due to the exclusion of sinter plant and coke ovens. Recycling of the most of the metallurgical wastes such as coke fines, mill scale, iron ore fines, LD slag, Limestone and Dolomite fines etc. are done as a COREX burden feedstock.   

Plant highlights / developments:

• In 2014 a COREX gas based 1.2 million t/a MIDREX DR plant was successfully added to produce Hot DRI. 
• COREX gas from both modules is partly used for Hot DRI production which is subsequently transferred to a new adjacent EAF steel plant via a hot transport system. The remaining export gas is still used for internal steel works use, the pelletizing plant and the power plant for co-firing.
• A recovery in excess of 95% of COREX slag could be done through slag granulation plant and is used in the manufacture of cement.
• Jindal’s COREX plant has been able to surpass its rated capacity by more than 20 - 25%, producing quality hot metal for steelmaking.
• During the relining in 2012 and 2013 an Arial Gas Distribution System was introduced in the reduction shaft of each COREX module. As a result of new developments (more even gas distribution, less burden weight on the DRI screws, more even flow of the material through the reduction shaft, etc.) an improvement of the process itself could be achieved: (a) Improved gas distribution, (b) Lower dp over the reduction shaft (c) Significant increase in Shaft Lifetime - the time from one shaft cleaning to the next shaft cleaning that occurred at JSW Steel on a regular basis has now been elongated to more than one year.

POSCO, Pohang Works, Republic of Korea

This COREX plant, POSCO (COREX C-2000 – Capacity: 0.8 Mtpa), started in 1995 adjacent to five existing blast furnaces. The COREX gas was utilized for power generation. In parallel with the signature for the COREX plant contract in December 1992, POSCO and PRIMETALS started working together for the development of the FINEX process of iron making.

Further developments:

• In 2002 the COREX plant of POSCO, Pohang Works was converted into the FINEX F-0.6M.
• Demonstration Plant with a nominal capacity of 2000 t/d commenced operation in 2003.
• In July 2014 the operation was stopped and currently it is under investigation to relocate the plant to India.

Baosteel Group, China

The first industrial COREX C-3000 of 1.5 MTPA capacities was built at the new steel works of Baosteel in Luojing at the outskirts of Shanghai. It was the largest COREX process plant in the world which successfully generated hot metal on November 8th 2007. The plant started-up in November, 2007. The contract for a second COREX C-3000 plant (COREX Module 2) was signed in December 2007 and started-up successfully in March 2011. Both Corex plants for Baosteel in Shanghai were supplied by Siemens Metals Technologies. Module 02 was more advanced as compared to COREX Module 01 which subsequently resulted in a successful performance guarantees test shortly after start-up where all agreed performance parameters were achieved and even exceeded. A significant increase in Shaft Lifetime was achieved by BAOSTEEL COREX plant module 02 where no shaft cleaning was necessary during its operation time of 1.5 years.

Further developments:

• Due to declining prices for heavy plate and as part of a strategic realignment of production in the Shanghai area, Baosteel decided to cease steel production in the Luojing Works and dismantle the individual steelmaking installations, including the two COREX plants. It rebuilt the dismantled installations in various Chinese steel works. The COREX Module 01 has been transferred to Bayi Iron & Steel Co Limited in the Xinjiang Province, a steelmaker belonging to the Baosteel Group.
• The COREX plant at Bayi Steel will allow local coal to be used, which are significantly cheaper in Xinjiang area.
• COREX gas can be used as a fuel gas in the downstream facilities to generate electricity or for the production of direct-reduced iron in a region that has almost no resources of natural gas.

Essar Hazira Ltd. India

Essar Hazira Ltd. relocated the two COREX plants (C-2000) from former Hanbo, Korea to their steelworks in Hazira, near Surat in Gujarat, India. The first plant has been started-up successfully in August 2011. Start-up of the second plant took place in December 2011. The COREX gas is mainly utilized at the existing MIDREX DR Modules to minimize natural gas consumption and for internal heating purposes.