Effect of Direct Reduced Iron (DRI) on Dephosphorization of Molten Steel by Electric Arc Furnace Slag

Abstract

We investigated the effect of direct reduced iron (DRI) addition on dephosphorization of molten steel by electric arc furnace (EAF) slag at 1823 K (1550°C). Various phenomena such as CO gas evolution and slagmaking by gangue oxides in DRI were experimentally observed at each reaction step. Thermodynamic behaviors of phosphorus, oxygen, and carbon were strongly dependent on DRI content. Basicity, which is the thermodynamic driving force of dephosphorization, decreased with the increasing DRI content because SiO 2 concentration in the slag was proportional to DRI addition. The excess free energy of P 2 O 5 increased with the increasing SiO 2 content in slag. A higher DRI content made dephosphorization difficult by decreasing the basicity and stability of P 2 O 5 in the slag. Therefore, when using DRI in EAF process, it is very important to control the basicity of slag.

The Preparation of High-Purity Iron (99.987%) Employing a Process of Direct Reduction–Melting Separation–Slag Refining

“…Secondly, The dephosphorization reaction in the refining process is carried out between slag and metal. Previous studies by other researchers and us [13][14][15][16][17][18][19] have clearly investigated the mechanism of dephosphorization between slag and metal. Firstly, phosphorus in iron is oxidized to (P 2 O 5 ) with the conditions of an oxidizing atmosphere or an oxidizing slag (FeO), as shown in Equation (4).…”

Clean production and utilisation of hydrogen in molten salts

“…Currently, steel is commercially produced using two technologies of (a) the integrated blast furnace-basic oxygen furnace (BF-BOF) 28 or (b) the direct reduced iron-electric arc furnace (DRI-EAF). 29,30 Blast furnaces use iron ore, scrap metal and coke to produce impure molten iron for conversion in the BOF, along with CO 2 emissions. Moreover, apart from CO 2 , other hazardous emissions such as SO 2 and NO x are also formed from the oxidation of sulphur, nitrogen and other impurities in coal and coke with negative consequences on human health.…”

Effect of partially reduced highly fluxed DRI pellets on impurities removal during steelmaking using a laboratory scale EAF

“…In India, 53% of steel is produced by Electric route while 47% produced by oxygen route; that's why DRI-EAF route become an essential point of study in the Indian steel-making scenario [2][3][4]. Now, DRI became the main source of iron feedstock for steelmaking industries due to its inherent chemical and physical properties like virgin nature, low sulphur content, uniformity of composition, easy transport & handling, uniform density & shape [5][6][7][8]. Most of these DRI are used as a replacement of iron ore lump only but not as a blend of lime and iron oxide.…”

“…Results of the Mn removal as a function of time under different %R values fluxed DRI are shown in Figure-3(c).It is obvious that Mn removal is higher under conditions 30%R compare to 50 and 80%R value fluxed DRI due to availability of higher value of total FeO content in slag.Carbon removalRemoval of Carbon as a function of time under different %R value fluxed DRI materials is presented in. Carbon removal mainly takes place as per the following reactions[21] [C]+ O2 (g) = {CO} (g) ; …… ΔG 0 = −142000−40.79T J•mol -1 (4)[C]+ (FeO) = {CO} (g) + [Fe] ; …… ΔG 0 = 115000−98.18T J•mol -1(5)…”