Corex Process - iron Manufacturing Technology

These slides provides you all the details about corex process for manufacturing iron.

1. IRON MANUFACTURING TECHNOLOGY COREX PROCESS

2. Metallurgy & Material Engineering Group Members Usama Hassan (332) Asfand Shahid (333) Junaid Illahi (334) Asad Jamil (335) Ahmer Ejaz (336)

3. COREX PROCESS Smelting Reduction Process Combination of Melter Gasifier & Reduction Shaft Lump iron ore or pellets, non-coking coal, and oxygen as main inputs Counter Current Principle Alternative to Blast Furnace

4. Why do we seek alternative to Blast Furnace? CHALLENGES The conventional blast furnace route is too costly and energy-intensive to keep pace with dynamic market changes, where even short- and medium-term fluctuations show their dramatic impact on iron production. The need to use coke and sinter makes it much more difficult to fulfil ever stricter environmental regulations and to achieve economical competitiveness . Rising energy demand, continuous price increases for natural gas and raw materials, and steadily decreasing quality of iron ore.

5. Why do we seek alternative to Blast Furnace? SOLUTION Corex is besides FINEX the only reliable alternative to the conventional blast furnace route. Corex will make you less dependent on price trends for raw materials. Corex provides you with the key technology for producing hot metal in an economically and ecologically sustainable manner. It frees from the need to invest in the operation and maintenance of coking and sinter plants because these additional facilities are not needed at all.

6. Differences between COREX & Blast Furnace

7. Differences between COREX & Blast Furnace

8. Differences between COREX & Blast Furnace The main differences between Corex and a conventional blast furnace route are Non-coking coal can be used directly as a reducing agent and energy source Up to 80% of the iron oxide fraction can be lump ore; no sintering is required Pure oxygen instead of nitrogen-rich hot blast

9. Salient Features Developed by Siemens VAI. Commercially most successful among SR technologies. Work is carried out in 2 reactors. Reduction shaft & Melter-gasifier. Commercial units in operation Korea : POSCO India : JSW Steel & Essar Steel ltd South Africa: Mittal-SALDANHA China : Baosteel

10. How do Commercial Unit Look Like…?

11. EXPLAINING THE CONSTRUCTION

12. WORKING Charge is charged into a reduction shaft where they are reduced to direct reduced iron (DRI) by a reduction gas moving in counter flow. Discharge screws convey the DRI from the reduction shaft into the Melter –Gasifier. In Melter - Gasifier final reduction and melting takes place. Hot metal and slag tapping are done as in conventional blast furnace practice. The gas leaving the reduction shaft is cooled and cleaned and is used for a wide range of applications. Its exhaust gases are used in MIDREX Process.

13. WORKING ELABORATED Reduction Shaft Iron ore, pellets and additives (limestone and dolomite) are continuously charged from the top. Some amount of coke is also added to the shaft to avoid clustering . The reduction gas is injected through the bustle located about 5 meters above the bottom of the shaft at 850°C and over 3-bar pressure. The gas moves in the counter current direction to the top of the shaft and exits from the shaft at around 250°C. The iron bearing material gets reduced to over 95% metallization in the shaft and is termed as DRI. Subsequently, six screws discharge the DRI from the reduction shaft into the Melter - Gasifier.

14. WORKING ELABORATED The Melter - Gasifier can largely be divided into three reaction zones Gaseous free board zone (upper part or dome) Char bed (middle part above oxygen tuyeres) Hearth zone (lower part below oxygen tuyeres) The hot DRI at around 600-800 °C along with limestone and dolomite are continuously fed into the Melter-Gasifier through DRI down pipes. The DRI down pipes are uniformly distributed along the circumference near the top of the melter-gasifier so as to ensure uniform distribution of material over the char bed.

15. WORKING ELABORATED Additionally non-coking coal, quartzite and required quantity of coke are continuously charged by means of lock hopper system. The operating pressure, in the melter-gasifier is in excess of 3 bars. Oxygen plays a vital role in COREX process for generation of heat and reduction gases. It is injected through the tuyeres, which gasifies the coal char generates CO. The hot gases ascend upward through the char bed. The sensible heat of the gases is transferred to the char bed, which is utilized for melting iron and slag and other metallurgical reactions. The hot metal and slag are collected in the hearth.

16. Materials for the production of 1000 kg hot metal at a COREX plant

17. Typical analysis of COREX hot metal and slag

18. ADVANTAGES It substantially reduces specific investment costs compared with conventional blast furnace steelmaking process; lowers the production costs 15% to 25% compared with a blast furnace, Outstanding overall environmental compatibility, due to reduction in CO2 generated per ton of iron production; Use of COREX export gas for a wide range of applications, Use of a wide variety of iron ores and coals, Elimination of coking plants, Hot-metal quality suitable for all steel applications. Integrated electrical power generation possible. Combined production of DRI possible.

19. DISADVANTAGES It has the limitation in distributing the coal and DRI in the optimised manner in the Melter-Gasifier . The coal consumption in Corex is much higher than in any other iron making process. The system is maintenance oriented, including cooling gas compressor for recycling part of COREX gas for cooling the hot gases from the melter-gasifier. It is provided with very sophisticated gas cleaning facilities. There are three gas cleaning streams for cleaning the total gas generated in the process. The process is sensitive to the quality of inputs particularly with respect to quality

20. THERE IS ALWAYS A GOOD REASON FOR COREX Corex fulfils all additional requirements beyond an economical and reliable iron making unit. Examples include JSW in India, where two Corex plants were erected for a steelworks in an isolated area with no access to natural gas or electricity; Baosteel in China, where a new steelworks was erected in a water protection area with a demand for electricity; and ArcelorMittal South Africa, where a Corex-DR combination forms the iron making basis for a steelworks in an environmentally restricted area. The expansion to a Corex-DR combination plant at JSW underlines the flexibility of Corex to respond to actual market demands in the iron and steel business.