Kobe Steel has developed the ITmk3® Process, which produces high-purity granular iron by utilizing iron ore concentrate and non-coking coal. The ITmk3® Process is distinctive with reduction, carburizing, melting and slag separation occurring promptly at lower temperature.
The ITmk3® Process completely bucks conventional concepts of ironmaking. Kobe Steel regards it as the third generation of ironmaking technology, following the current major blast furnace-basic oxygen furnace (BF-BOF) process and the direct reduction (DR) process represented by the Midrex® Process. The ITmk3® Process can make reduction reaction take place in approximately 10 minutes, compared with 8 hours by the BF-BOF process and 6 hours by the DR process.
In the current iron ore market, the effective utilization of low-grade iron ore is an issue, as it has become more and more difficult to secure high grade iron ore. At the present, low-grade iron ore is processed into iron ore fines, high-grade iron ore concentrate and pellets through grinding, beneficiation and firing, and is fed into the blast furnace and DR plant. In the ITmk3® Process, iron ore concentrate and non-coking coal are mixed together and agglomerated into green pellets. These pellets, fed into a rotary hearth furnace (RHF), are changed into granular iron, namely Iron Nuggets, through reduction and melting occuring at a stroke.
Furthermore, the ITmk3® Process utilizes non-coking coal as the reductant, which is abundant in volume worldwide in comparison to metallurgical coal utilized by blast furnaces. Therefore, the ITmk3® Process not only widens the sourcing of coal procurement but also decreases the environmental impact by eliminating the coking coal process required for blast furnaces.
Overcoming various difficulties, the utilization of non-coking coal as a reductant for low-grade iron ore is embodied by the ITmk3® Process. This process is gaining attention all over the world as a breakthrough technology owing to the following advantages: reducing the cost for ironmaking, widening the range of raw materials for the process, and reducing the burden on the environment.
Kobe Steel has constructed the world`s first commercial plant in Minnesota, USA in cooperation with Steel Dynamics Inc. (SDI)
- Hoyt Lakes, Minnesota, USA
- Production capacity:
- 500,000 metric tons per year
- Commencement of Operation:
- January, 2010
- Name of Company:
- Mesabi Nugget Delaware, LLC
(Joint venture company established by Kobe Steel and SDI in 2006)
- Iron Nuggets for use in SDI`s EAFs
- Kobe Steel's Role:
- Providing the ITmk3® Process license, engineering, major equipment supply and supervision
- Utilization of low-grade iron ore
Iron ore fines produced by minutely grinding low-grade iron ore are beneficiated in order to produce high-grade iron ore concentrate. Conventionally, iron ore concentrate must be fired to produce fired pellets, which are the feedstock for ironmaking in blast furnace and DR plants. However, in the ITmk3® Process, Iron Nuggets, which are equivalent to pig iron, can be produced directly from green pellets without the firing process to produce fired pellets.
- Utilization of non-coking coal
Non-coking coal can be used as a reductant in the ITmk3® Process. Non-coking coal is abundant all over the world and low in market price compared with coking coal used by blast furnaces.
- Flexible operation
ITmk3® is a simple process that uses conventional equipment. Therefore, plant operation is quite easy. Furthermore, a short retention time of approximate 10 minutes also facilitates the start up and stopping of operations.
Approximate 65% of the world's crude steel is now produced by the BF-BOF process. The BF-BOF process, of which the scale continues expanding, is said one of the most sophisticated ironmaking technologies. However, it is necessary to devise countermeasures in order to reduce the environmental impact since baking the coking coal to produce coke and sintering the iron ore fines to produce sintered ore are required for the BF-BOF process. On the other hand, the ITmk3® Process can decrease CO2 emission by approximately 20%*1 compared with Japanese blast furnaces*2 as coke and sintered iron ore are not used. In addition, the reduction volume of CO2 can increase in comparison to mini-blast furnaces used mainly in China and India.
*1 The unit energy consumption in the Japanese steel industry (BF-BOF process) is 20-30% lower than that of Western countries.
Research Institute of Innovative Technology for the Earth (January, 2008). International Comparisons of Energy Efficiency (Sectors of Electricity Generation, Iron and steel, Cement)
*2 Comparison figures of CO2 emission
High-purity iron units are required to produce high grade steel products, while the availability of such resources is becoming tight. Steel producers need to secure a stable supply of high-purity iron, and Iron Nuggets produced by the ITmk3® Process can offer solutions with its great advantages.
- High quality equivalent to pig iron:
Total Fe : 96-97%, slag-free
- Increased productivity in EAF/BOF:
Superior melting performance due to high density and small size of nuggets. Continuous feeding to steelmaking process is possible.
- Easy transportation & handling:
No re-oxidization and fine generation
- Laboratory testing
- Small pilot plant (3,000t/y) constructed and operated in Kobe Steel`s Kakogawa Works, Japan
- Pilot demonstration plant (25,000t/y) constructed and operated in Minnesota, USA
- 1st commercial plant construction started
- 2nd half 2009:
- Commissioning started
- Jan. 2010:
- Commencement of operation
ITmk3® pilot plant
Kobe Steel`s Kakogawa Works
ITmk3® Pilot Demonstration Plant
Silver Bay, Minnesota, USA
ITmk3® Pilot Demonstration Plant
Hoyt Lakes, Minnesota, USA
The ITmk3® Process consists of raw materials handling, reduction-melting, product handling and off-gas treatment.