Ironmaking in Rotary Hearth Furnace May17

Ironmaking in Rotary Hearth Furnace...

Ironmaking in Rotary Hearth Furnace Ironmaking in the rotary hearth furnace (RHF) is a direct reduction process which utilizes non-coking coal for the reduction of iron ore. The RHF is the process reactor which consists of a flat, refractory hearth rotating inside a stationary, circular tunnel kiln. Inside the RHF, direct reduction of iron ore or iron-bearing waste materials occurs, using coal as the reductant. RHF is not a new technology. It has been used successfully in a range of industrial applications which includes heat treatment, calcination of petroleum coke, waste treatment, and non-ferrous high-temperature metal recovery. The history of ironmaking in RHF goes back to the mid-1960s with the development of the ‘Heat Fast’ process by Midrex. Since then several ironmaking processes based on RHF have been developed. These include ‘Fastmet’ process/‘Fastmelt’ process, and ITmk3 process which were brought into commercial operation. These processes have been described in separate articles having links    http://ispatguru.com/fastmet-and-fastmelt-processes-of-ironmaking/, and http://ispatguru.com/itmk-3-process-of-making-iron-nuggets/. Other RHF processes are ‘Redsmelt’ process, ‘Inmetco’ process, ‘Iron Dynamics’ process, ‘DRyIron’ process, ‘Comet’ and ‘SidComet’ processes and Hi-QIP process. Redsmelt process The Redsmelt process technology has been developed to meet the growing demand for a low cost environmental friendly ironmaking alternative to the traditional blast furnace route. The plant with this process can be designed for a production capacity of 0.3 million tons per year to 1.0 million tons per year of hot metal. The process can treat a wide range of iron ore fines and waste materials from the steel plant. The Redsmelt process is based upon a RHF which reduces green pellets made out of iron ore, reductant fines and binders to produce hot, metallized direct reduced iron (DRI) which is charged to a submerged arc furnace (SAF). The process operates at high temperature and...

FASTMET and FASTMELT Processes of Ironmaking Nov15

FASTMET and FASTMELT Processes of Ironmaking...

FASTMET and FASTMELT Processes of Ironmaking Kobe Steel in collaboration with Midrex Technologies, Inc., a subsidiary of Kobe Steel in the USA, has developed the FASTMET process which is a coal based direct reduction process of iron making. The FASTMET process converts iron ore pellet feed, iron ore fines and/or metallurgical waste from the steel plant into direct reduced iron (DRI) using pulverized non coking coal as a reductant. The process uses a rotary hearth furnace (RHF) for the reduction reaction (Fig 1). The end product DRI can be hot briquetted (HBI), discharged as hot DRI into transfer containers, or cooled if cold DRI is needed. FASTMELT process is the FASTMET process with addition of an Electric Iron Melting Furnace (EIF) to produce liquid iron or hot metal. Hot DRI is directly discharged from the RHF into EIF and is melted to produce hot metal. Fig 2  A simplified cross section and plan view of a RHF The first commercial FASTMET plant was commissioned in April 2000 at Nippon Steel’s Hirohata works. A total of 5 plants have since been commissioned. The details of these plants are given in Table 1. Tab 1 FASTMET commercial plants Unit NSC Hirohata no. 1 NSC Hirohata no. 1 NSC Hirohata no. 1 JFE Fukuyama KSL Kakogawa RHF feed rate ton/Yr 190,000 190,000 190,000 190,000 16,000 Raw materials BOF dust BOF dust BOF dust BF dust, BOF dust BF dust, BOF dust, EAF dust Product application BOF feed, DRI BOF feed, DRI BOF feed, HBI BOF feed, DRI  BF & BOF feed, DRI It can be seen that this process is being presently used for utilization of the metallurgical waste of the steel plant. Besides metallurgical waste the process can also use iron ore fines having size which...