China
Africa
Explore chapters and articles related to this topic
The Advent of Steam and Mechanical Engineering
Published in Ervan Garrison, A History of Engineering and Technology Artful Methods, 2018
The open hearth or Siemens-Martin process was a much larger scale undertaking. Forty tons or more of liquid iron was used. The iron was heated with preheated gases from coal and natural gas at temperatures of 1000 degrees. The open-hearth process could use wrought iron and steel scrap, as well as pig iron. In the present day, a process known as “direct-reduction iron” produces iron pellets from ore by removing oxygen from the mineral using natural gas furnaces.
Kinetic studies on bituminous coal char gasification using CO2 and H2O mixtures
Published in International Journal of Green Energy, 2019
Junwei Chen, Weibin Chen, Ru Ji, Yang Jiao, Xidong Wang
Direct reduction is the process of reducing iron ore to metallic iron by gas reductant (CO, H2, etc.) or solid reductant below the softening temperature of iron ore. Increasing production of DRI can not only increase the proportion of quality steel (Soedarsono et al. 2014), but also reduce carbon dioxide emissions and other pollution produced during iron smelting (Kato 2010; Worrell, Price, and Martin 2001). According to the different types of a reductant, the DRI technology can be divided into gas-based DRI process and coal-based DRI process. The gas-based DRI process plays a leading role, because of its advantages of high production capacity, low energy consumption, and low pollutant emission (Huang, Yang, and Yi 2012; Zervas, Mcmullan, and Williams 2015). Nowadays, the production of gas-based DRI takes up 80% of the world total DRI production. Moreover, natural gas is the absolutely dominant gaseous reducing agent applied in the gas-based DRI process (Patel 2008).
Reduction kinetics of iron ore pellets with coal and coal dust: reduction relation with crystalline phases
Published in Mineral Processing and Extractive Metallurgy, 2018
Direct reduced iron provides scraps for steel industries. DRI is produced in the form of lumps or pellets. In a direct reduction process, varieties of reductants, namely lower grade coals, natural gas and charcoal, are used. The fast depletion of high-grade coking coal reserves restricts the use of coal in a conventional blast furnace-oxygen steel making route, whereas non-coking coal is being used for the production of DRI in a rotary kiln. In view of the depletion of coking coal, it is essential to develop the DRI process making use of non-coking coal or low-grade reductant. In 2002, India became the largest producer of sponge iron in the world with a production of 5.48 million tonnes and still it has retained its first slot in the world rating of sponge iron production. Around 84% of iron ore fines are exported to foreign countries at a throwaway price which causes huge economic loss to our country (Kumar et al. 2009; Gorantiwar and Shrivastava 2015). These fines can be suitably utilised for making pellets which can be subsequently reduced and used for making steel.
Red Mud: Fundamentals and New Avenues for Utilization
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Direct reduction of hematite present in red mud has been studied intensely. The direct reduction of iron ores reduces the iron oxides but does not separate it from gangue material. The product of an iron direct reduction process can be used as a feed for steelmaking in an electric arc furnace (Anameric and Kawatra 2007b). The following Equations 19–22 outline the reduction of iron oxides to iron (Chen, 2017).