Abstract: An apparatus for keeping an optimal penetration depth formed at the front end of an oxygen tuyere in the producing facilities of molten pig iron utilizing non-coking coal and a method for keeping the same. A sensor for measuring distance using a laser for continuously measuring the penetration depth, is provided. Comprised is a process computer for continuously receiving the measured penetration depth from the sensor and comparing the received penetration depth with a predetermined optimal penetration depth to obtain a difference between them, and for obtaining a changing amount of a pressure in a melter gasifier through a mutual relation between a predetermined changing amount of a pressure in the melter gasifier with that of the penetration depth using the difference between the actual penetration depth with the optimal penetration depth.

Abstract: Disclosed is a method for increasing the charring ratio of coal. In manufacturing an ingot iron using the coal, magnesium oxide or limestone is used as an additive for charring the coal. The additive increases the charring ratio of the coal while giving no affection onto slag. An MgO suspension or limestone suspension is mixed with the coal and thus obtained mixture is dried to attach MgO or the limestone onto the surface of the coal. The charring effect is increased and the using amount of coke can be reduced.

Abstract: An apparatus for and a method of melting fine particles containing carbon, capable of uniformly burning and melting the fine particles throughout the entire zone of the combustion flame. The apparatus includes a triple tube structure including an inner oxygen feeding section having an oxygen inlet tube provided with an oxygen feeding passage, a particle feeding section arranged surrounding the inner oxygen feeding section, comprising a particle inlet tube, a feeding tube and a feeding passage, and an outer oxygen feeding section arranged surrounding the particle feeding section, comprising an outer oxygen inlet tube, a feeding tube and a feeding passage. The front ends of the inner oxygen feeding tube, particle feeding tube and outer oxygen feeding tube constitute a nozzle which serves to inject the fine particles fed through the particle feeding tube together with air and/or oxygen flows respectively fed through the inner and outer oxygen feeding tubes to be burned and melted.