Separation Technologies for the Industries of the Future (1998) / Chapter Skim
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6 Steel Industry
6 Steel Industry
Pages 59-67
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From page 59... ...
The first is called the "integrated" segment because iron ore and coke (made from coal) are combined in blast furnaces to produce molten iron (called hot metal)
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From page 60... ...
Among integrated steel mills, there are also broad similarities between separation processes for raw materials and for products that are recycled and reused. Coke Production Traditional integrated steelworks use iron ore, coal, limestone, and oxygen or air to produce steel.
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From page 61... ...
Oxygen Steelmaking The integrated steelmaking industry relies almost entirely on oxygen processes to make steel from hot metal. A typical heat yields about 200 tons of finished steel in about 38 minutes from a charge of 80 percent carbon-saturated hot metal and 20 percent heavy steel scrap.
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From page 62... ...
Further refining downstream of the oxygen process may be required to control residual impurities and prevent inclusions. Better knowledge of the relationships between steel properties and the specific costs and benefits of better separation technologies could help prioritize research.
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From page 63... ...
For higher-quality steel products, such as flat rolled sheet and bar-quali~ steels, copper and other residual elements must be below specified levels in the EAF feed because they are not removed in the process and their presence may make it impossible to achieve the desired properties. A flat rolled steel, for example, may have a maximum allowable copper level of 0.1 percent, as opposed to 0.25 percent copper in typical automobile shredder scrap.
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From page 64... ...
Suitable feeds ideally contain no more than 3 percent silica plus alumina, but very few natural ores approach this level of purity. Therefore, the feed is usually finely ground, beneficiated by magnetic separation, flotation, or both, and reconstituted as fired oxide pellets before reduction.
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From page 65... ...
Although the coke ovens are one of the most obvious sources of gaseous and liquid emissions, all iron and steelmaking processes produce similar emissions. Therefore, research on the separation of fine particulates from gases and liquids could yield broad benefits for the industry as a whole.
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From page 66... ...
Dissolution of the solid copper into a sulfide matte, or even liquid aluminum, is another promising technique, but difficulties include sulfides or aluminum being attached to the scrap and high costs. Improved Ore for Direct Reduction of Iron Separation methods based on gravity or density can be used to improve the quality of ore for DRI.
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From page 67... ...
. reties In scrap · separation processes to produce very high grade DRI feeds · better understanding of the behavior of fine particulates in gaseous or liquid media
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