188宝金博页面版

By: Nabil Daoud TaklaQatar Steel Company Ltd. (QASCO)This paper was originally presented at theAISU’s 2nd Electric Furnace Symposium inDamascus, Syria, October 18-20, 1998.V arious process routes areapplied to produce steel. Theseroutes can be divided into twocategories “from ore to steel” and “fromscrap to steel.” There is no doubt that asfar as energy consumption is concerned,the route “from scrap to steel” is moreadvantageous, because only meltingenergy is needed. Therefore, this methodof steel making has been successfullyapplied for more than a century. In com-ing years, there will be a tremendousincrease in EA F steel production ofhigher value steel. These higher valuesteels require lower residuals and, inmany cases, lower nitrogen levels thansteels normally produced in the EA F.Also, the rapid developments of UltraHigh Powered Electric A rc Furnaceshave contributed to the vast interest inDRI as an alternative charge for EAFs inthe developing, as well as, industrializedcountries all over the world.DRI is a valuable source of iron forthe production of quality steel. With the available direct reduction technol-ogy, which has expanded remarkablyduring the recent years, the DR-EA Froute for steel making has establishedmany advantages over scrap melting such as:• Well-known chemical composition• Low content of impurities (residual elements, sulfur and phosphorus)• Permits dilution with low-cost scrap• Easy to handle, store and transfer• Permits automatic continuous charging• More predictable price structure• Stable electrical power inputQatar Steel Company’s managementhas selected the DR-EAF route of steel-making due to the many advantages ofusing DRI. Moreover, Qatar is blessedwith abundant natural gas resources. Forthese reasons, DRI has been utilized byQA SCO for producing the requiredquality of steel. Normally two steelgrades (High Tensile and Mild Steel) areproduced. QASCO’s EAFs operate usinga 95 percent DRI charge, which is one ofthe highest ratios in the steel-producingworld. This paper presents a detaileddescription of the major equipment andthe practice for producing steel by utiliz-ing a high percentage of DRI. Severalactivities have been adopted to increaseproductivity in the EA F, mainly thereduction of tap-to-tap time. Moreover,within two years QASCO will have alsoused HBI as a part of the EAF charge. IntroductionHistorical DataQASCO is the first integrated steel plantin the Gulf region, and was establishedin 1974 by three shareholders:• Government of the State of Qatar: 70%• Kobe Steel Ltd., Japan: 20%• Tokyo Boeki Ltd., Japan: 10%The operation was started in March1978, with the prime objective to producesteel reinforcing bars to meet the domes-tic demand, as well as the demand of surrounding countries. Since its start-up,the plant has made undaunted progresstowards full utilization of all its produc-tion units with the required standards of quality and efficiency. A t presentQASCO is considered as one of the bestand most reliable quality steel producersin the region.In 1998 Qatar took over the manage-ment from the Japanese and in 1997 thegovernment of Qatar purchased theJapanese shares, thus establishing itself asa wholly nationalized company.DIRECT FROM MIDREX 2ND QUARTER 1999 3Utilization of Sponge Iron in Electric Arc Furnaces