Review of Innovative Energy Savings Technology for the Electric Arc Furnace

Abstract

A review of the energy innovations for the electric arc furnace (EAF) steelmaking route is discussed. Preheating of scrap using vertical and horizontal shafts that have been commercially successful in lowering the energy consumption to as much as 90 kWh/t reaching almost the operational limit to heating input scrap materials into the EAF is discussed. Bucket-type and twin-shell preheaters have also shown to be effective in lowering the overall power consumption by 60 kWh/t, but these have been less effective than the vertical shaft-type preheaters. Beyond the scrap preheating technologies, the utilization of waste heat of the slags from the laboratory scale to the pilot scale has shown possible implementation of a granulation and subsequent heat exchange with forced air for energy recovery from the hot slags. Novel techniques to increase metal recovery have shown that laboratory-scale testing of localized Fe concentration into the primary spinel crystals was possible allowing the separation of an Fe-rich crystal from an Fe-depleted amorphous phase. A possible future process for converting the thermal energy of the CO/ CO 2 off-gases from the EAF into chemical energy was introduced.

Sulfide Capacity of CaO-SiO₂-FeO-Al₂O₃-MgO_satd. Slag

“…(3). where C S 2− is the sulfide capacity of the slag; (wt%S) is the sulfur content in weight percent in the slag; P O2 and P S2 are the partial pressures of oxygen and sulfur, respectively; and K (1) , a O 2− , and f S 2− denote the equilibrium constant of Eq. (1), activity of free oxygen ion in the slag, and activity coefficient of sulfide ion in the molten slag, respectively.…”

“…(3), the slope of the logarithmic plot of the O 2 − activity and sulfide capacity is expected to be unity. (8) where K (1) is the equilibrium constant of Eq. (1), a O 2− is the activity of O 2 − ions, and f S 2− is the Henrian activity coefficient of S 2 − ions in the slag.…”

“…[1][2][3] Because of the strict global regulation of greenhouse gases, these recent technological improvements have gained attention due to their environmental benefits.…”

Achieving a Carbon Neutral Society without Industry Contraction in the Five Major Steel Producing Countries

“…The CO 2 emissions of the basic metals industry can be estimated from Equation (6). The estimated CO 2 emissions indicate that Korea has a CO 2 emissions increment of 3.43 million tons per one million USD in consumed input energy source costs.…”

“…The estimated CO 2 emissions indicate that Korea has a CO 2 emissions increment of 3.43 million tons per one million USD in consumed input energy source costs. q i " m ε i x m`cε i x c`eε i x e (6) where q i is the CO 2 emissions of country "I", m ε i is the elasticity factor value of industry sector (2) for country "I", c ε i is the elasticity factor value of industry sector (7) for country "I", e ε i is the elasticity factor value of industry sector (16) for country "I", x m is the input cost of industry sector (2), x c is the input cost of industry sector (7), and x e is the input cost of industry sector (16). Specifically, Japan and Germany demonstrated a more pronounced sensitivity in CO 2 emissions with higher prices in electricity as the energy source compared with China and the US, but were comparatively less sensitive to the total cost of coal/peat as the energy source.…”