Nkk Corporation

Nippon Kokan Kabushiki Kaisha

Yoshihito Iwata

Noboru Sakamoto

Hiroshi Saito

Satoshi Kinoshiro

Tadashi Mochizuki

Yohichi Ishibashi

Akiko Sakashita

Takanori Akiyoshi

Hiroshi Fukuya

Yoshihiko Kawai

Tsuneo Miyashita

Shinichi Isozaki

Hiroaki Miyahara

Noboru Sato

Koji Satomi

Yoichi Nimura

A method for recovering zinc oxide comprises the steps of: agglomerating a dust; charging the agglomerate to a molten iron in a melting furnace; collecting a dust generated from the melting furnace; recycling a part of the collected dust and recovering another part of the collected dust. An apparatus for recovering zinc oxide comprises: an agglomeration unit for agglomerating a dust containing iron oxide and zinc oxide; a melting furnace for accepting the agglomerate and for holding the molten iron for reducing the dust; and at least two units of dust collector for collecting the dust containing zinc oxide generated from the melting furnace.

Method for recovering zinc oxide from dust

A method for analyzing steel which comprises: grinding an analysis area of a steel ingot; sealing the analysis area with a sealing section of a cell for generating fine particles; again grinding the analysis area, while an argon gas is introduced into the cell; irradiating a pulsed laser beam of 10.sup.8 W/cm.sup.2 or more onto the analysis area at an irradiating spot of at least 1 mm.sup.2 to generate the fine particles; moving the irradiating spot; and transferring the generated fine particles by the argon gas to a plasma emission analysis for analysis. A further method for analyzing steel comprises: solidifying a molten steel sample, forming a red-hot sample; putting the sample into a sample holding section of a sample chamber under a purified argon gas atmosphere, the sample holding section having an inner curved surface the same as a curved surface of the sample; irradiating a pulsed laser onto the sample to remove a sample surface layer of 25 .mu.m or more of the sample and to generate fine particles from the sample; and exciting the fine particles by a plasma emission analyzer to analyze the composition of the fine particles.

Method for analyzing steel and apparatus therefor

A method for analyzing solid sample comprises the steps of: introducing an inert carrier gas into a cell; a preliminary treatment step of irradiating laser beam to a sample surface of the solid sample in the inert carrier gas, the laser beam having a pulse half width of 0.001 .mu.sec or more, a pulse energy density of 0.001 GW/cm.sup.2 or more, and a frequency of 100 Hz or more; generating fine particles in the inert carrier gas on a condition that a rate of fine particles generation, V (.mu.g/sec), and selection ratio, S, satisfy the following equations, the selection ratio being a retio of a concentration of a target element for analysis within the fine particles to a concentration of the target element for analysis within the solid sample;

Method for analyzing solid sample

Mini-pellets made of raw materials of fine powder iron ores are indurated, and effected with diffusion bond. A plurality of said treated mini-pellets are combined with calcium ferrites at the surface layers thereof. Thus, agglomerated ores are produced, wherein main grain sizes of said fine powder iron ores are not more than 5 mm, and are subjected to a primary pelletization with flux, and solid fuels are coated in a secondary pelletization to produce the mini-pellets of 3 to 9 mm diameter, and the produced mini-pellets are undertaken with induration in a travelling grate typed sintering furnace. Depending upon the present agglomerated ores and the producing method therefor, the raw materials may be selected from a wide range of grain sizes, and a blow faculty is enough to be small, and producing yield of the agglomerated ores may be increased, having improved qualities of high RI and low RDI.

Agglomerated ores and a producing method therefor

A method for continuously manufacturing fired pellets, comprising the steps of: using raw materials comprising a first iron ore fine of from 30 to 70 wt. % and a second iron ore fine of from 70 to 30 wt. %, the first iron ore fine comprising an iron ore fine of from 50 to 80 wt. % having a particle size of up to 0.044 mm and an iron ore fine of from 50 to 20 wt. % having a particle size of from over 0.044 mm up to 0.5 mm, the second iron ore fine comprising an iron ore fine of from 40 to 70 wt. % having a particle size of from over 0.5 mm up to 8 mm and an iron ore fine of from 60 to 30 wt. % having a particle size of up to 0.5 mm; adding a powdery flux and water to the above-mentioned raw materials to form a mixture; forming the mixture into green pellets having a particle size of from 3 to 12 mm; covering the surfaces of the green pellets with a powdery solid fuel in a prescribed amount; and drying, igniting and then firing the green pellets in an endless travelling grate type firing furnace into fired pellets.

Method for continuously manufacturing fired pellets

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Kawasaki, Japan

Yoshihito Iwata