سازوکار احیای کنسانتره هماتیت-مگنتیت توسط مخلوط گرافیت-کربنات کلسیم به روش هوگانس

نوع مقاله : علمی و پژوهشی

نویسندگان

گروه مهندسی متالورژی و مواد، دانشکده مهندسی، دانشگاه فردوسی مشهد.

چکیده

در این تحقیق، سازوکار احیای کنسانتره هماتیت-مگنتیت توسط مخلوط گرافیت-کربنات کلسیم در دمای °C1000 مورد بررسی قرار گرفته است. بررسی­ها نشان داد مراحل اولیه تا میانی احیاء (تا 63%) عمدتا تحت تاثیر انتقال حرارت داخل محفظه می­باشد. در مراحل میانی تا پایانی فرآیند احیاء، نفوذ گازی به فصل مشترک FeO-Fe به همراه واکنش گازی شدن کربن کنترل کننده فرآیند احیاء می­باشند. قبل از شروع واکنش گازی شدن کربن، نرخ احیاء نسبتا کند بوده و بر اساس نتایج آنالیز XRD، آهن فلزی تشکیل نمی­شود. بررسی مقطع نمونه­های احیاء شده نشان داد پیشروی فرآیند احیاء به صورت توالی شیمیایی وعمدتا از سطح بیرونی استوانه به سمت داخل می­باشد. تصاویر میکروسکوپ الکترونی روبشی(SEM) نشان دهنده تشکیل آهن فلزی به صورت رشته­های زینتر شده می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

The Mechanism of the Reduction of Hematite-Magnetite Concentrate by Graphite-Calcium Carbonate Mixture in Hoganas Process

نویسندگان [English]

  • Seyyed Mohammad Ali Haghi
  • Ahad Zabett
  • Mostafa Mirjalili
Department of Materials Engineering, Faculty of Engineering, Ferdowsi University of Mashhad
چکیده [English]

In this study, the mechanism of reduction of hematite-magnetite concentrate (HMC) by graphite-calcium carbonate reductant mixture at 1000 °C was investigated. The initial and middle stages of the reduction process (up to 63%) are mainly affected by the heat transfer inside the crucible. In the middle and final stages of the reduction process, the gaseous diffusion to the FeO-Fe reaction interface and the carbon gasification by CO2 jointly controlled this progress. The reduction rate was relatively slow below the temperature at which the carbon gasification by CO2 commences. According to the XRD analysis, prior to the carbon gasification, the metallic iron was not found. The reduction of the HMC hollow cylinder proceeded topochemically mainly from the outer surface. The SEM micrographs indicated the formation of sintered iron whisker.

کلیدواژه‌ها [English]

  • reduction
  • Graphite–Calcium Carbonate Mixture
  • Mass transfer
  • Carbon Gasification
  • kinetics
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