Kiichi Narita

Mathematical model of direct reduction shaft furnace and its application to actual operations of a model plant

Abstract The shaft furnace process provides the greatest energy efficiency and the highest productivity among all direct reduction processes. Most shaft furnaces producing sponge iron, however, have been designed empirically up to the present. In order to optimize operations a mathematical model has been developed to be applied to shaft furnace design. The model, whose reduction rate equations are derived from the three-interface model, involves both mass and heat balances. The models rate parameters were determined according to the parameter fitting method, so that calculated values might agree, as closely as possible, with measured values in an experimental shaft furnace with an inside diameter of 0.25 m and a reduction zone height of 2.7 m. Commercial applicability of the mathematical model was also confirmed by simulations in an actual shaft furnace.

Solid electrolyte for the determination of sulfur in liquid iron

Abstract In order to find a sulfide solid electrolyte with high ionic conductivity, the electrical conductivities of CaS-based solid sulfides at 800–1400°C were measured. From the dependence of the conductivity on sulfur partial pressure, the ionic conduction of these sulfides was evaluated. CaS containing TiS 2 was found to have high ionic conductivity. Also, sulfur determination in liquid carbon-saturated iron by emf measurement using a CaS-TiS 2 solid electrolyte is reported.

Desulphurization of Molten Pig Iron by Means of Injection Method

Kiichi NARITA, Akitsu TOMITA , Yasuo kintooKA, and Yoshitomo SATOH Synopsis: A study has been made of cold model experiments and hot model experiments on the desulphurization of molten pig iron by means of injecting calcium carbide. The results reported here are summarized as follows: 1) By the cold model experiments, effects of stirring solution in a ladle model is significant when a lance is immersed more than half of the bath depth. In this case the stirring effect is not affected by the immersion position of the lance in a ladle model, either center or wall-side. 2) A hot model experiments based on the cold one indicated that both results for desulphurization effects coincided very well, for example, effects of the immersion depth of lance could be applied to effects of desulphurization of molten pig iron. 3) Injection method, when a lance is immersed more than half of the bath depth, has a high degree of utilization of calcium carbide and a large effect of desulphurization per weight of molten pig iron. (Received Mar. 23, 1970)