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Title: Verification of Steelmaking Slags Iron Content Final Technical Progress Report

Abstract

The steel industry in the United States generates about 30 million tons of by-products each year, including 6 million tons of desulfurization and BOF/BOP slag. The recycling of BF (blast furnace) slag has made significant progress in past years with much of the material being utilized as construction aggregate and in cementitious applications. However, the recycling of desulfurization and BOF/BOP slags still faces many technical, economic, and environmental challenges. Previous efforts have focused on in-plant recycling of the by-products, achieving only limited success. As a result, large amounts of by-products of various qualities have been stockpiled at steel mills or disposed into landfills. After more than 50 years of stockpiling and landfilling, available mill site space has diminished and environmental constraints have increased. The prospect of conventionally landfilling of the material is a high cost option, a waste of true national resources, and an eternal material liability issue. The research effort has demonstrated that major inroads have been made in establishing the viability of recycling and reuse of the steelmaking slags. The research identified key components in the slags, developed technologies to separate the iron units and produce marketable products from the separation processes. Three products are generated from themore » technology developed in this research, including a high grade iron product containing about 90%Fe, a medium grade iron product containing about 60% Fe, and a low grade iron product containing less than 10% Fe. The high grade iron product contains primarily metallic iron and can be marketed as a replacement of pig iron or DRI (Direct Reduced Iron) for steel mills. The medium grade iron product contains both iron oxide and metallic iron and can be utilized as a substitute for the iron ore in the blast furnace. The low grade iron product is rich in calcium, magnesium and iron oxides and silicates. It has a sufficient lime value and can be utilized for acid mine drainage treatment. Economic analysis from this research demonstrates that the results are favorable. The strong demand and the increase of price of the DRI and pig iron in recent years are particularly beneficial to the economics. The favorable economics has brought commercial interests. ICAN Global has obtained license agreement on the technology from Michigan Tech. This right was later transferred to the Westwood Land, Inc. A demonstration pilot plant is under construction to evaluate the technology. Steel industry will benefit from the new supply of the iron units once the commercial plants are constructed. Environmental benefits to the public and the steel industry will be tremendous. Not only the old piles of the slag will be removed, but also the federal responsible abandoned mines from the old mining activities can be remediated with the favorable product generated from the process. Cost can be reduced and there will be no lime required, which can avoid the release of carbon dioxide from lime production process.« less

Authors:
Publication Date:
Research Org.:
Michigan Technological University, Houghton, MI
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
892748
Report Number(s):
ID14046
MTU #000910, E21726; TRN: US200719%%833
DOE Contract Number:
FC36-01ID14046
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ACID MINE DRAINAGE; BLAST FURNACES; CARBON DIOXIDE; ECONOMIC ANALYSIS; IRON; IRON ORES; IRON OXIDES; METAL INDUSTRY; PILOT PLANTS; PROGRESS REPORT; SANITARY LANDFILLS; SEPARATION PROCESSES; SLAGS; VERIFICATION; steelmaking slags; iron units; separation; pig iron; DRI (Direct Reduced Iron); steel mills; metallic iron; iron ore; blast furnace; acid mine drainage treatment.

Citation Formats

J.Y. Hwang. Verification of Steelmaking Slags Iron Content Final Technical Progress Report. United States: N. p., 2006. Web. doi:10.2172/892748.
J.Y. Hwang. Verification of Steelmaking Slags Iron Content Final Technical Progress Report. United States. doi:10.2172/892748.
J.Y. Hwang. Wed . "Verification of Steelmaking Slags Iron Content Final Technical Progress Report". United States. doi:10.2172/892748. https://www.osti.gov/servlets/purl/892748.
@article{osti_892748,
title = {Verification of Steelmaking Slags Iron Content Final Technical Progress Report},
author = {J.Y. Hwang},
abstractNote = {The steel industry in the United States generates about 30 million tons of by-products each year, including 6 million tons of desulfurization and BOF/BOP slag. The recycling of BF (blast furnace) slag has made significant progress in past years with much of the material being utilized as construction aggregate and in cementitious applications. However, the recycling of desulfurization and BOF/BOP slags still faces many technical, economic, and environmental challenges. Previous efforts have focused on in-plant recycling of the by-products, achieving only limited success. As a result, large amounts of by-products of various qualities have been stockpiled at steel mills or disposed into landfills. After more than 50 years of stockpiling and landfilling, available mill site space has diminished and environmental constraints have increased. The prospect of conventionally landfilling of the material is a high cost option, a waste of true national resources, and an eternal material liability issue. The research effort has demonstrated that major inroads have been made in establishing the viability of recycling and reuse of the steelmaking slags. The research identified key components in the slags, developed technologies to separate the iron units and produce marketable products from the separation processes. Three products are generated from the technology developed in this research, including a high grade iron product containing about 90%Fe, a medium grade iron product containing about 60% Fe, and a low grade iron product containing less than 10% Fe. The high grade iron product contains primarily metallic iron and can be marketed as a replacement of pig iron or DRI (Direct Reduced Iron) for steel mills. The medium grade iron product contains both iron oxide and metallic iron and can be utilized as a substitute for the iron ore in the blast furnace. The low grade iron product is rich in calcium, magnesium and iron oxides and silicates. It has a sufficient lime value and can be utilized for acid mine drainage treatment. Economic analysis from this research demonstrates that the results are favorable. The strong demand and the increase of price of the DRI and pig iron in recent years are particularly beneficial to the economics. The favorable economics has brought commercial interests. ICAN Global has obtained license agreement on the technology from Michigan Tech. This right was later transferred to the Westwood Land, Inc. A demonstration pilot plant is under construction to evaluate the technology. Steel industry will benefit from the new supply of the iron units once the commercial plants are constructed. Environmental benefits to the public and the steel industry will be tremendous. Not only the old piles of the slag will be removed, but also the federal responsible abandoned mines from the old mining activities can be remediated with the favorable product generated from the process. Cost can be reduced and there will be no lime required, which can avoid the release of carbon dioxide from lime production process.},
doi = {10.2172/892748},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Oct 04 00:00:00 EDT 2006},
month = {Wed Oct 04 00:00:00 EDT 2006}
}

Technical Report:

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  • The current trend in the steel industry is a gradual decline in conventional steelmaking from taconite pellets in blast furnaces, and an increasing number of alternative processes using metallic scrap iron, pig iron and metallized iron ore products. Currently, iron ores from Minnesota and Michigan are pelletized and shipped to the lower Great Lakes ports as blast furnace feed. The existing transportation system and infrastructure is geared to handling these bulk materials. In order to expand the opportunities for the existing iron ore mines beyond their blast furnace customer base, a new material is needed to satisfy the needs ofmore » the emerging steel industry while utilizing the existing infrastructure and materials handling. A recent commercial installation employing Kobe Steel’s ITmk3 process, was installed in Northeastern Minnesota. The basic process uses a moving hearth furnace to directly reduce iron oxides to metallic iron from a mixture of iron ore, coals and additives. The resulting products can be shipped using the existing infrastructure for use in various steelmaking processes. The technology reportedly saves energy by 30% over the current integrated steelmaking process and reduces emissions by more than 40%. A similar large-scale pilot plant campaign is also currently in progress using JFE Steel’s Hi-QIP process in Japan. The objective of this proposal is to build upon and improve the technology demonstrated by Kobe Steel and JFE, by further reducing cost, improving quality and creating added incentive for commercial development. This project expands previous research conducted at the University of Minnesota Duluth’s Natural Resources Research Institute and that reported by Kobe and JFE Steel. Three major issues have been identified and are addressed in this project for producing high-quality nodular reduced iron (NRI) at low cost: (1) reduce the processing temperature, (2) control the furnace gas atmosphere over the NRI, and (3) effectively use sub-bituminous coal as a reductant. From over 4000 laboratory tube and box furnace tests, it was established that the correct combination of additives, fluxes, and reductant while controlling the concentration of CO and CO2 in the furnace atmosphere (a) lowers the operating temperature, (b) decreases the use of reductant coal (c) generates less micro nodules of iron, and (d) promotes desulphurization. The laboratory scale work was subsequently verified on 12.2 m (40 ft) long pilot scale furnace. High quality NRI could be produced on a routine basis using the pilot furnace facility with energy provided from oxy-gas or oxy-coal burner technologies. Specific strategies were developed to allow the use of sub-bituminous coals both as a hearth material and as part of the reaction mixture. Computational Fluid Dynamics (CFD) modeling was used to study the overall carbothermic reduction and smelting process. The movement of the furnace gas on a pilot hearth furnace and larger simulated furnaces and various means of controlling the gas atmosphere were evaluated. Various atmosphere control methods were identified and tested during the course of the investigation. Based on the results, the appropriate modifications to the furnace were made and tested at the pilot scale. A series of reduction and smelting tests were conducted to verify the utility of the processing conditions. During this phase, the overall energy use characteristics, raw materials, alternative fuels, and the overall economics predicted for full scale implementation were analyzed. The results indicate that it should be possible to lower reaction temperatures while simultaneously producing low sulfur, high carbon NRI if the right mix chemistry and atmosphere are employed. Recommendations for moving the technology to the next stage of commercialization are presented.« less
  • The Federal Government has initiated, expanded, and is accelerating a cost-shaped program with the iron and steel industry to develop innovative, cost-effective programs for new energy-saving technologies. The purpose of this document is to identify opportunities for research and development in the iron and steel industry, giving due consideration to the many barriers that impede the implementation of new technology. These technology sectors also reflect the following three fundamental criteria that DOE has formulated to guide the selection of projects for consideration in this program: the project must have the potential to save energy; the project must be considered cost-effectivemore » when fully developed; when fully developed, the project must be considered reliable and have no negative effect on capacity. Concepts considered for commercial development have been selected because of their significant potential for conserving energy and/or critical fuel forms and on the assumption that they would involve: preparation of proposals by or in conjunction with companies associated with the steel industry, to ensure the practicality of the concept in a steelmaking environment; cost sharing with companies associated with the steel industry; and demonstration of technology that would provide an option for the iron and steel industry to be less dependent on natural gas and distillate fuels. In addition, the program is aimed at stabilizing employment and increasing U.S. strategic security.« less
  • The direct steelmaking program is proceeding essentially on schedule. The physical chemistry research programs at Carnegie Mellon University and the Massachusetts Institute of Technology, concerned with ore-slag, ore-melt, and melt-slag reactions, are proceeding on schedule and are generating information on reaction rates, gas evolution rates, and mass-transfer and heat-transfer rates that will help in understanding and modeling the smelting process. Laboratory modeling of the refining process assisted in the design of a pilot-scale continuous refiner. Several runs of the continuous refiner from late October to early December yielded data that are currently being analyzed. 19 figs.