RU2014109085A - METHOD OF ELECTRIC Smelting of metallized pellets in an arc furnace - Google Patents

Abstract

1. The method of electrofusion of metallized pellets in an arc furnace, including the supply of pellets (briquettes and other bulk materials) through hollow (tubular) electrodes, fuel through fuel-oxygen burners (TKG) to slag, oxygen through tuyere nozzles, as well as measuring activity ( carbon) in a metal by the method of E.D.S. and temperature by a sensor in the furnace bath, characterized in that the consumption of metallized pellets (V, kg / s) is carried out depending on the thermal power of the bath (Δq, kW) and the heating rate of the metal in it (V, kg / min), while pellets are determined by the expression where Δq = Q / τ + (Q + Q + Q), where Q is the energy consumption for melting, kW · h / t; Q, Q, Q - heat input to the bath from the afterburning of carbon monoxide (CO), fuel from TCG and exothermic reactions in the furnace, kW; G is the initial weight of the metal in the furnace before the pellets are fed into the bath, kg; is the average heat capacity of the metal, kJ / (kg · ° C), and the metal heating rate V is determined as, where are the metal temperatures continuously measured by the sensor in the furnace bath (° C ) at times τ and τ (min), and also find the current weight of the metal in the furnace, equal to G = G + V · τ, and the rate of decarburization of the metal according to the expression V = (CC) / (τ-τ), [C,% ] / sec, where Cu C is the carbon concentration at times τ and τ, where Cu is determined along the LMO melting process by the activity of oxygen (a) in the metal, the measured Ikom E.D.S. and temperature. 2. The method according to claim 1, characterized in that the pellet flow rate (V, kg / s) is regulated according to V = V, then the Δq value is reduced, and if V> V, then the Δq value is increased to the level when V = V, while the optimal speed metal heating in the furnace V is defined as V = [(TT) -T] / τ = (ΔV, + (1539 + 85 [C,%]) - T) / τ, where T, T, T is the optimal metal temperature in the bath arc furnace temperature face

Claims (5)

1. The method of electrofusion of metallized pellets in an arc furnace, including the supply of pellets (briquettes and other bulk materials) through hollow (tubular) electrodes, fuel through fuel-oxygen burners (TKG) to slag, oxygen through tuyere nozzles, as well as measuring activity ( carbon) in a metal by the method of E.D.S. and temperature sensor in the furnace bath, characterized in that the flow rate of metallized pellets (V_OK, kg / s) is carried out depending on the thermal power of the bath (Δq_at, kW) and the heating rate of the metal in it (V_t, kg / min), while the consumption of pellets is determined by the expression $$V_{\mathrm{about}\mathrm{to}}=(\Delta q_{\mathrm{at}}/(V_t*\overline{c})-G_0)/\tau$$

 Where Δq_at= Q_at/ τ + (Q_ex+ Q_CO+ Q_t), where Q_at - power consumption for melting, kW · h / t; Q_CO, Q_t, Q_ex - heat input to the bath from the afterburning of carbon monoxide (CO), fuel from the TCG and exothermic reactions in the furnace, kW; G₀ - the initial weight of the metal in the furnace before starting the supply of pellets into the bath, kg; $$\overline{c}$$

 is the average heat capacity of the metal, kJ / (kg · ° C), and the metal heating rate V_t determine how $$V_t=(T_d^{"}-T_d^{\text{'}\text{'}})/({\tau }_2-{\tau }_{\mathrm{one}})$$

where $$T_d^{\text{'}\text{'}}$$

 and $$T_d^{"}$$

 - metal temperatures continuously measured by the sensor in the furnace bath (° C) at time instants τ_one and τ₂ (min), and also find the current metal weight in the furnace equal to G_r= G₀+ V_OK· Τ, and the decarburization rate of the metal according to the expression V_c= (C₂-C_one) / (τ₂-τ_one), [С,%] / sec, where С_one and C₂ - carbon concentrations at times τ_one and τ₂, and C_one and C₂ determined during the process of melting LMOs by oxygen activity (and_[O]) in metal, measured by the sensor E.D.S. and temperature. 2. The method according to p. 1, characterized in that the consumption of pellets (V _ok , kg / s) is regulated by V _t = V _{t (opt)} , then the value Δq _{in is} reduced, and if V _t > V _{t (opt)} , then the value of Δq _in increase to a level when V _t = V _{t (opt)} , while the optimal heating rate of the metal in the furnace V _{t (opt)} is defined as V _{t (opt)} = [(T _opt -T _liquor ) -T _m ] / τ = (ΔV _l , + (1539 + 85 [С,%]) - T _m ) / τ, where T _opt , T _liquor , T _m - metal temperature optimal in the arc furnace bath, liquidus temperature and current metal temperature in the oven, ° C; ΔT _l is the degree of metal overheating above the liquidus line, which is, for example, equal to 75 ± 15 ° С in an arc furnace; [C,%] - the current carbon concentration, determined using the sensor E.D.S. and temperature, which is placed at the end of the lance body. 3. The method according to p. 1, characterized in that the afterburning of CO is carried out with oxygen coming from the nozzles of the tuyere and TKG to the slag in proportion to the volume of CO above the bath, which is determined, for example, by the dependence of V _CO = 3.1 · 10 ^-4 · V _c · G _τ m ³ / s, where G _τ is the current weight of the metal in the furnace, equal to G _τ = G ₀ + V _ok · τ, and the rate of decarburization of the metal is equal to V _s = (C ₂ -C ₁ ) / (τ ₂ -τ ₁ ), [С,%] / sec, where С ₁ and С ₂ are carbon concentrations at time instants τ ₁ and τ ₂ , and С ₁ and С _{2 are} determined during the LMO melting process by oxygen activity ( a _[O] ) in the metal, as measured by the E.D.S. and the temperature set at the end of the lance. 4. The method according to p. 1, characterized in that the consumption of pellets (V_OK, kg / s) optimize according to the universal criterion V_t/ V_{t (wholesale)}= K_wholesale, = 1 ± 0.05, where k_wholesale, = 1 ± 0.05 characterizes the equality V_t/ V_{t (wholesale)} with an error of determination, for example, 5%. 5. The method according to p. 1, characterized in that the carbon concentration [% C] in the metal is determined by the activity of oxygen (a _[O] ) and the temperature of the metal (T _m , ° C) using an E.D.S. sensor at the end of the tuyere, for example, by the correlation expression a _[O] = 0.0025 ± 0.0032 / [% C], and $$a_{[O]}=\exp (\frac{E_{\mathrm{one}}\ln a_0^{"}-E_2\ln a_0^{\text{'}\text{'}}}{E_{\mathrm{one}}-E_2})$$

where E ₁ and E ₂ are the measured values of E.D.S. in the cells of the sensor (mV), and $$a_0^{\text{'}\text{'}}$$

and $$a_0^{"}$$

- oxygen activity in standard sensor comparison electrodes.