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...

Tecnored Process for Ironmaking Apr30

Tecnored Process for Ironmaking...

Tecnored Process for Ironmaking Tecnored process was developed by ‘Tecnored Desenvolvimento Tecnológico S.A.’ of Brazil and is based upon a low pressure moving bed reduction furnace which reduces cold bonded, carbon bearing, self-fluxing, and self-reducing pellets. Reduction is carried out in a short height shaft furnace of distinct design at typical reduction temperatures. The process produces hot metal (liquid iron). Tecnored technology has been conceived and developed to be a ‘coke-less’ ironmaking process, thus avoiding the investment and operation of environmentally harmful  coke ovens besides significantly reducing green-house gas emissions in the production of hot metal. Tecnored process uses a combination of hot and cold blast and requires no additional oxygen. It eliminates the need for coke plants, sinter plants, and tonnage oxygen plants. Hence, the process has much lower operating and investment costs than those of traditional ironmaking routes. Tecnored process is flexible with regard to the type of iron bearing and carbon bearing raw materials which it can process. The ability of the process to smelt either pellets or briquettes, or even mixed charges of both, provides means of using a wide range of alternative feed materials. The process has got good productivity and high energy efficiency. Tecnored process is also being claimed to be suitable for producing ferro alloys such as ferro manganese. History of development The history of the development of the Tecnored process comprises different phases with different goals, testing a wide range of raw materials and using distinct sizes and concepts of the reactor. During the period 1979 to 1985, development activities were carried out regarding the use of pyrite cinder containing self-reducing pellets as metallic burden in cupola furnaces. This concept of self-reduction was adapted to develop the new process.  In 1985 the concept of the Tecnored...

HYL Process for Direct Reduction of Iron Ore Apr22

HYL Process for Direct Reduction of Iron Ore...

HYL Process for Direct Reduction of Iron Ore HYL process is designed for the conversion of iron ore (pellet/lump ore) into metallic iron, by the use of reducing gases in a solid-gas moving bed reactor. Oxygen (O2) is removed from the iron ore by chemical reactions based on hydrogen (H2) and carbon monoxide (CO) for the production of highly metallized direct reduced iron (DRI)/hot briquetted iron (HBI). HYL process is presently marketed under ‘Energiron’ trademark. HYL process for direct reduction of iron ore was the fruition of research efforts begun by Hojalata y L.mina, S.A. (later known as Hylsa), at the beginning of the 1950s. After the initial evaluation of the concept, it was decided to install a process using a tunnel furnace and several runs were undertaken. The first batch was made by using an ancient furnace (which had been built to heat plate) on the 5th of July, 1950. One part of crushed ore of size ranging from 12 mm to 25 mm was mixed with 40 % coke breeze and 15 % limestone of the same granulometry as the ore. This mixture was put into clay crucibles and into 2 iron pipes, each one with a diameter of 100 mm and a length of 1 meter. 20 kg of good quality of DRI was produced. The first gas based plant, with a design capacity of 50 tons per day, was unable to reach acceptable levels of metallization. During the 18 months of its operation, it underwent several changes, including the installation of a natural gas reformer with the object of improving the reducing gas. Finally, its operation was suspended during early 1955. After this discouraging attempt, several experiments were carried out and a pilot plant was assembled to put the new...

Midrex Process for Direct Reduction of Iron Ore Apr09

Midrex Process for Direct Reduction of Iron Ore...

Midrex Process for Direct Reduction of Iron Ore Midrex is an ironmaking process, developed for the production of direct reduced iron (DRI). It is a gas-based shaft furnace process is a solid state reduction process which reduces iron ore pellets or lump ore into DRI without their melting using reducing gas generally formed from natural gas. The principle of the reduction process using reducing gas is shown in Fig 1. Fig 1 Principle of reduction process using reducing gas The history of the Midrex process goes back to 1966 when Donald Beggs of the Surface Combustion Corporation conceives the idea for the Midrex direct reduction process.  The original process was developed by the Midland-Ross Co., which later became Midrex Technologies, Inc. It is now a wholly owned subsidiary of Kobe Steel. A pilot plant was built in Toledo, Ohio in 1967. The first commercial plant, having a production capacity of 150,000 tons per year, was built in Portland, Oregon, in 1969. The genius of the Midrex process is its simplicity. Donald Beggs’ concept of combining stoichiometric natural gas reforming with shaft furnace direct reduction of iron ore was a breakthrough innovation which has stood the test of time. Since 1969, DRI production through Midrex process has crossed 500 million tons. Production from many of the Midrex plants exceeds their design capacity. Each year since 1987, DRI production through Midrex process is over 60 % of the total global production of DRI. The process was immature in 1978, when Kobe Steel began the construction of a plant with a production capacity of 400,000 tons/year in the State of Qatar. Kobe Steel significantly modified the design, exploiting the company’s technologies developed through blast furnace operation, and stabilized the then new process. On the other hand, Midrex...

Direct Iron Ore Smelting Process for Ironmaking Mar28

Direct Iron Ore Smelting Process for Ironmaking...

Direct Iron Ore Smelting Process for Ironmaking Direct iron ore smelting (DIOS) process is a smelting reduction process for the production of hot metal (liquid iron). It is a two-stage process which has been developed in Japan. It uses non-coking coal in a powder or granular form to smelt iron ore fines into liquid iron (hot metal) and hence, there is no necessity of a coke ovens plant and a sintering plant. The ore fines are pre-reduced in a fluidized bed furnace and are charged in the smelting reduction furnace along with non-coking coal and fluxes. Oxygen is blown into the smelting reduction furnace. The two stages of the DIOS process consists of (i) pre reduction of iron ore in preliminary reduction furnace (PRF), and (ii) the final reduction and melting in the smelting reduction furnace (SRF). The pre reduction of the ore is carried out in two steps utilizing the exhaust gas from the SRF. Each of the steps uses a fluidized bed reactor which is designed as a vertical furnace. The development of the DIOS process started in 1988 in Japan as a joint research project among eight iron manufacturing companies who had, prior to 1988, been studying the smelting-reduction process individually. This project was sponsored by MITI, the Japanese Ministry of International Trade and Industry. Japanese companies and Japan Iron and Steel Federation (JISF) actively supported the development of the process during the period of 1988 to 1996. Core technology study necessary for the construction of the pilot plant was done during the period 1988 to 1990. During this period core technologies were established. These core technologies include (i) an increase in the thermal efficiency of a SRF, (ii) the technology to be integrated with a PRF, (iii) the technology for...

Romelt Process for Ironmaking Mar20

Romelt Process for Ironmaking...

Romelt Process for Ironmaking Romelt process for ironmaking is a smelting reduction process for the production of hot metal (liquid iron). The process has been developed by The National University of Science & Technology ‘MISiS’, Russia (formerly known as Moscow Institute of Steel and Alloys). The development work of the process started in 1978 when a group of ‘MISiS’ scientists led by Vladimir Roments began working on designing of this process. The first patent in Russia was obtained in 1979. A pilot production plant having a hearth area of 20 sq m and with a capacity 40,000 tons of hot metal per year was commissioned in 1985 at the Novolipetsk Iron and Steel Works (NLMK). The pilot plant was designed by Moscow Gipromez. The design of the reliable Vanyukov’s furnace was taken as the prototype for this new method of manufacturing hot metal. The process was tested and mastered at this pilot plant between 1985 and 1998. During this period forty-one campaigns were carried out, each of which included startup and slowdown, with full tapping of hot metal and slag from the furnace. More than 40,000 tons of hot metal was produced in the pilot plant during this period and used further in basic oxygen furnace (BOF) for steelmaking. The first industrial plant for hot metal production based on Romelt technology is being built at Myanmar. The plant has been designed by Leningrad Gipromez and being supplied by Tyazpromexport, a subsidiary of Rostec. This plant has a capacity of 200,000 tons per year and is based on the processing of iron ore without its beneficiation from Pang Pet ore deposit. Pang Pet ore deposits have Fe content of up to 29 %. The plant will use non-coking coal from Kye Thee coal fields. The...