Nippon Steel Corporation

Japan Metals & Chemicals Co., Ltd.

Chikara Saito

Hiroyuki Katayama

Hidetake Ishikawa

Tetsuharu Ibaraki

Michitaka Kanemoto

Masaki Fujita

Nobuyoshi Nishihara

Masao Yamauchi

Masatoshi Kuwabara

Tetu Nishi

Hiromitsu Moridera

Hiroyuki Nakama

Kouichi Yuta

Hirofumi Wakimoto

Tuneyuki Inoue

Toshiaki Okuhara

A method of in-bath smelting reduction comprises the step of selectively supplying powder materials into a gas upflow region or a gas downflow region within a furnace during the time that oxygen-containing gas is concurrently being blown into the furnace from a top lance. Also disclosed is an in-bath smelting reduction furnace for carrying out the method.

Method for in-bath smelting reduction of metals

A process which enables high-chromium alloy such as ferrochromium heretofore obtained by the use of electricity to be produced less expensively in higher yield of chromium by the smelting reduction using solid carbonaceous material such as coke in the place of electricity. The process of smelting reduction is so performed in the top and bottom blowing converter divided into two stages: the first stage for carrying out the converter operation under continued supply of the raw materials containing pre-reduced chromium oxide (chromium ore) and the second stage for carrying out the converter operation under suspended supply of the raw materials containing the pre-reduced chromium oxide, and the first stage of converter operation is carried out under conditions such that the temperature of the molten metal remains at or below 1,650.degree. C. and the ratio of the volume of the gas generated per minute by the substances supplied through the tuyere for bottom blowing to the combined weight of the molten metal and the molten slag falls in the range of 100 to 2,500 [Nl/min.t] and the second stage of converter operation is carried out under conditions such that the temperature of the molten metal remains at or below 1,650.degree. C., the ratio of the volume of gas generated per minute by the substances supplied through the tuyere for bottom blowing to the combined weight of the molten metal and the molten slag falls in the range of 100 to 1,800 [Nl/min.t].

Process for production of high-chromium alloy by smelting reduction

A process for producing high chromium steel is disclosed which comprises supplying molten iron in a smelting furnace with a solid chromium source, carbonaceous powder and oxygen-containing gas in amounts so controlled as to keep the melt at a temperature in the range of less than 1650.degree. C. and above the minimum melt temperature at the specific carbon and chromium levels in the melt and which is capable of performing preferential decarbonization while inhibiting the oxidation of chromium.

Process for producing high chromium steel

Process for producing formed coke for metallurgical use from coal powder by continuously heating with a high temperature gas as heating medium for carbonizing agglomerated coal which are made of coal powder and a binder such as coal tar, pitch and petroleum asphalt, comprising providing tuyeres for introducing gas at the middle and the lower parts of an upright type carbonization oven, adjusting temperature of the gas to be supplied to the tuyere at the middle part at 600.degree. to 800.degree. C, adjusting the supply rate of the gas so as to maintain the temperature of the gas on the agglomerated coal at 300.degree. to 500.degree. C, and further adjusting the supplied heat to the lower part of the carbonization oven including the lower tuyere to amount less than 50% of the total supplied heat.

Process for producing formed coke for metallurgical use

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Kitakyushu, Japan

Chikara Saito