DESULFURIZATION METHOD OF MOLTEN PIG IRON USING COMBINATION OF MECHANICAL STIRRING AND GAS STIRRING

摘要

PROBLEM TO BE SOLVED: To achieve rapid desulfurization to a low sulfur range by enhancing reaction efficiency of a desulfurizing agent without causing operation inhibition using combination of stirring by an impeller and stirring by gas.;SOLUTION: Desulfurization treatment is performed under the condition that: a basic unit of CaO of a desulfurizing agent is 5 kg/t or more; a refining vessel diameter D, a blade diameter d and a nozzle position P satisfy "d/2PD/2"; the number of nozzles n and a central angle θ of neighboring nozzles satisfy "360/n-30≤θ≤360/n+30" ; a depth of molten iron H_m, a height of an impeller b and an immersion position of the impeller h satisfy "0.2≤h/H_m1-b/H_m" ; a maximum gas flow rate Q_g,max and a minimum gas flow rate of the gas Q_g,min satisfy "1≤Q_g,max/Q_g,min≤2" ; a stirring power density by the impeller ε_i and a stirring power density by gas ε_g satisfy "0.012≤ε_g/ε_i≤0.15"; and the desulfurization treatment is performed while blowing gas into the molten pig iron when the desulfurizing agent is not added thereto.;COPYRIGHT: (C)2016,JPO&INPIT