ENVIRONMENTAL FRIENDLY CONSUMPTION OF SCRAP TIRES IN EAF'S TO SAVE POWER & CARBON
DOI:
https://doi.org/10.7494/mafe.2008.34.1.13Keywords:
scrap tires, EAF, carbon, coke, powerAbstract
World wastes nearly 1.3 billions of tire/year, while Iran wastes 8 millions pieces of tire annually. This study and investigation shows that waste tires can be a substitute for coal & coke in EAF as environmental friendly. In this study Esfahan Steel Company (ESCo) consumed waste tires with 6 Mg capacity EAF. Thirteen grades of steel including Iow, medium & high C content as well as Iow & high alloys were produced during 73 heats. The result was very successful & coke consumption rate reduced from 18 to 0 kg/Mg of steel. Electricity consumption decreased from 448 to 388 kWh/Mg. Stack gas analysis & measuring was done and the achieved results indicate the polluted gases content such as CO, NOX and SO2 is much less than the limited range. Industrial tests continued in Iran Alloy Steel Co. where 20 heats were made in 40 Mg capacity EAF with 30 MVA transformer capacities. The results are as follows: waste tires can be substitute for C in EAF steelmaking & the costs lowered by 5 €/Mg; the use of waste tires for additional chemical energy can further decrease electric energy consumption up to by 10-25%. The average S% in steel products was lower than 0.026; the environment is improved by consumption of waste tires in EAF instead of burying them in landfills. The process is reliable, economic & ecological. The large sized scrap tires like these of graders, mining earth movers, trucks & farm tires can be charged in EAF as whole used tires. Dioxin formation peaks at 200°C and decreases unsymmetrically with increasing temperature. Tires have virtually no Hg.
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References
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