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The blast furnace sim

The zone temperatures are the lesson's (about 700, 900, 1200 and 1900 °C, and iron tapped at about 1500 °C).

The blast furnace · covers the GCSE, IGCSE, O-Level topic

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What the sim shows

The zone temperatures are the lesson's (about 700, 900, 1200 and 1900 °C, and iron tapped at about 1500 °C). The lesson puts about 700 °C "near the top"; that is the upper part of the stack, and the gas leaves the very top at about 200 °C. The hottest place is just in front of the tuyeres, not the very bottom: the hearth is about 1500 °C. The iron forms as a hot solid at 700 to 900 °C and melts lower down, at about 1150 °C, once carbon has dissolved in it; exam answers write it as 2Fe(l). Masses per tonne of iron are worked by moles from the equations, with an example ore of 90% Fe₂O₃, pure coke and pure limestone, so they are approximate. Molten iron is about 7 g/cm³ and molten slag about 2.8 g/cm³, so the slag floats; the pools' depths are drawn to one scale, so the slag layer is about 0.77 times as deep as the iron below it. The pieces show the charge's volume: about 53% coke, 38% ore and 9% limestone (approximate bulk densities). Cold blast: a blast at room temperature brings no heat, so each zone's rise above room temperature is taken as 63% of the hot one, from a simple heat balance per mole of carbon (110.5 kJ from burning, about 25 kJ in the hot coke, about 79 kJ from air at about 1100 °C); using one share for every zone is this figure's simplification. The furnace makes about 7 t of iron a minute; a tap of 300 t is this figure's example. The clock runs 120 times faster than real time. Pieces, gas and drops are a picture, not a count.

  • Iron ore
  • Coke
  • Limestone
  • Molten iron
  • Slag
  • Glow: hotter is brighter

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