Nisshin Steel Co., Ltd.

Other

Yasushi Fukui

Minoru Saito

Masanori Matsuno

Tadaaki Miono

Hideo Miyake

Hiroshi Tanaka

Masahiko Souda

Masaya Yamamoto

Yoshikazu Morita

Shoichi Matsuo

Tsuguyasu Yoshii

Kazushi Sakamoto

Yasumi Ariyoshi

Kazunari Nakamoto

Akihiro Asaba

Atsushi Ando

Ralph Sattmann

Katsuhiko Masaki

Oliver Humbach

Atsushi Mizuno

Hidenori Ochiai

Yukihiro Morita

Tomomitsu Yaginuma

Toru Ikeda

The purpose of the present invention is to provide a method for recovering calcium-containing solid components from steelmaking slag, with which it is possible to easily increase the calcium recovery rate. With the method, steelmaking slag is immersed in an aqueous solution containing carbon dioxide, and calcium in the steelmaking slag is made to leach out into the aqueous solution. Next, the immersed steelmaking slag is removed from the aqueous solution, and, subsequently, the pH of the aqueous solution is increased. When solid components precipitated by doing so are recovered, it is possible to recover solid components containing 20% or more by mass in terms of calcium atoms.

Method for recovering calcium-containing solid component from steelmaking slag and recovered solid component

An aqueous solution containing 30 ppm or more of carbon dioxide is brought into contact with a steel-making slag to elute phosphorus and calcium contained in the steel-making slag into the aqueous solution. Subsequently, carbon dioxide is removed from the aqueous solution to precipitate a mixture comprising a phosphorus compound and a calcium compound. In this manner, a mixture comprising a phosphorus compound and a calcium compound and containing phosphorus in an amount of 1% by mass or more in terms of phosphorus atom content can be produced.

Phosphorus and calcium collection method, and mixture produced by said collection method

A method for measuring trace quantities of OH groups in quartz glass comprises preparing a set of test pieces comprising a reference test piece from a blank of a quartz glass body whose OH group content is known and a sample test piece from a quartz glass body whose OH group content is to be measured, having two planar planes faced to each other, setting the sample test piece and the reference test piece in an infrared spectrophotometer; successively irradiating perpendicular to one of the two planar planes an incident infrared radiation in a wavelength region of approximately 2500 nm to approximately 2950 nm, while simultaneously detecting the outgoing radiation spectrum from the other plane; obtaining the difference of the outgoing radiation spectrum of each of the test pieces; selecting the absorbance peak assigned to OH groups at a wavelength of 2720 nm to obtain the peak height thereof; and calculating the concentration of OH groups from the peak height in the sample test piece.

Method for measuring concentration of trace amount of OH-groups contained in quartz glass

A separator for a low-temperature fuel cell comprises a stainless steel substrate S having a surface to which carbonaceous particles such as graphite particles GP or carbon black aggregates CA adhere with dotted distribution. The carbonaceous particles are preferably bonded through a diffusion layer DL to the surface of the substrate S. The carbonaceous particle-dispersed layer may be a plating layer in which graphite particles GP or carbon black aggregates CA are dispersed or formed by thermal decomposition of organic components in a carbonaceous particle-dispersed paint applied to the surface of the substrate S. Since carbonaceous particles free from oxide films adhere to the surface of the acid-resistant stainless steel substrate S, contact resistance of the separator is sufficiently low. Consequently, a power generator having a plurality of fuel cells laminated together exhibits high power-generating efficiency with less heat loss caused by a Joule heat.

Separator for low temperature type fuel cell and method of production thereof

A metal vapor 12 passing through a guide duct 13 from a vapor source 10 to a steel strip 1 is sampled through a takeoff pipe 14 to a measuring chamber 15. The metal vapor is irradiated with a measuring beam 20 in the chamber 15, to detect the absorbance of luminous energy in the metal vapor. The detected value of absorbance is used for the quantitative calculation of the metal vapor 12 passing through the guide duct 13, and the opening ratio of a shutter 17 provided in the guide duct 13 is adjusted on the basis of the calculation result so as to control the flow amount of the metal vapor 12 passing through the guide duct 13. In the case where a large amount of the metal vapor 12 passes through the guide duct 13, the amount of the metal vapor 12 reaching the measuring beam 20 is reduced by partially discharging the metal vapor 12 from the measuring chamber 15. Since the deposition amount of a plating metal is directly controlled in response to the amount of the metal vapor 2 passing through the guide duct 13, the amount of a deposited plating layer is controlled with high accuracy and with a quick response time in a continuous vapor deposition coating line.

Atomic absorption analysis for measuring and controlling the amount of a

A Zn-Mg binary coating layer formed on a steel sheet has the tri-layered structure that the first sublayer composed of a Zn-Mg alloy having Mg concentration of 0.5 wt. % or less, the second sublayer composed of a Zn-Mg alloy having Mg concentration of 7 wt. % or more and the third sublayer composed of a Zn-Mg alloy having Mg concentration of 0.5 wt. % or less are successively laminated. The coating layer may have the penta-layered structure wherein sublayers composed of a Zn-Mg alloy having Mg concentration of 2-7 wt. % are additionally interposed between the high-Mg and low-Mg sublayers. A Zn-Fe or Zn-Fe-Mg alloy layer may be formed at the boundary between the substrate steel and the coating layer. The adhesion ratio of the first sublayer to the top sublayer is preferably 1.2 or more, while the high-Mg sublayer is preferably conditioned to the mixed structure of a Zn.sub.2 Mg phase with a Mg-dissolved Zn phase. Due to the specified lamellar structure, the intrinsic properties of the high-Mg sublayer is sufficiently exhibited, and the secondary paint adhesiveness of the coating layer is excellent. Consequently, the coated steel sheet is useful as structural members or parts exposed to a severe corrosive atmosphere in various industrial fields.

Steel sheet coated with Zn-Mg binary coating layer excellent in

A Mg source 3 is received in a vessel 1 having an opening 8, and the vessel 1 is heated at 670.degree. C. or higher to effuse Mg vapor through the opening 8. Since the vessel 1 is filled with Mg vapor, Mg is evaporated from molten state under stable condition without fluctuations in evaporation speed. The Mg vapor is effectively consumed for vapor deposition. A reflector plate may be provided at the outlet of the opening 8, or a duct for introducing Mg vapor from the vessel to the surface of a substrate sheet may be provided. In order to evaporate Mg from stabilized molten state, operational conditions are preferably determined so as to satisfy the relationships of W.sub.1 /W.sub.2 &lt;0.6.times.(P.sub.Mg /V.sup.3) and W.sub.1 /W.sub.2 &lt;0.04.times.P.sub.Mg, wherein W.sub.1 represents the area (mm.sup.2) of the opening 8, W.sub.2 represents the evaporation surface area (mm.sup.2) of the Mg source 3, P.sub.Mg represents Mg vapor pressure (torr.) and V represents the degree of vacuum.

Formation of magnesium vapor with high evaporation speed

A Zn--Mg binary coating layer formed on a steel sheet has the tri-layered structure that the first sublayer composed of a Zn--Mg alloy having Mg concentration of 0.5 wt. % or less, the second sublayer composed of a Zn--Mg alloy having Mg concentration of 7 wt. % or more and the third sublayer composed of a Zn--Mg alloy having Mg concentration of 0.5 wt. % or less are successively laminated. The coating layer may have the penta-layered structure wherein sublayers composed of a Zn--Mg alloy having Mg concentration of 2-7 wt. % are additionally interposed between the high-Mg and low-Mg sublayers. A Zn--Fe or Zn--Fe--Mg alloy layer may be formed at the boundary between the substrate steel and the coating layer. The adhesion ratio of the first sublayer to the top sublayer is preferably 1.2 or more, while the high-Mg sublayer is preferably conditioned to the mixed structure of a Zn.sub.2 Mg phase with a Mg-dissolved Zn phase. Due to the specified lamellar structure, the intrinsic properties of the high-Mg sublayer is sufficiently exhibited, and the secondary paint adhesiveness of the coating layer is excellent. Consequently, the coated steel sheet is useful as structural members or parts exposed to a severe corrosive atmosphere in various industrial fields.

Steel sheet coated witn Zn-Mg binary coating layer excellent in

An iron-based heat-generating material excellent in oxidation resistance at an elevated temperature which comprises an iron-based alloy capable of generating heat by passing electricity therethrough and a coating of aluminum and oxygen formed on the surface of the alloy, the amount of the oxygen in the coating is less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. The material can be prepared by vacuum evaporation of Al onto the surface of the iron-based alloy wherein an oxygen partial pressure in a vacuum gaseous atmosphere for the vacuum evaporation is adjusted so that there is formed on the surface of the alloy a coating consisting of aluminum and oxygen, the amount of the oxygen in the coating being less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. When the material is heated in ambient or oxidizing atmosphere, an outermost layer of the coating is rapidly converted to Al.sub.2 O.sub.3.

Iron-based material having excellent oxidation resistance at elevated

Vapor deposition for formation of plating layer

A steel strip is cleaned by sputtering-etching with ion beams of argon. By the sputtering-etching, an oxide film of easily oxidable elements such as chromium and silicon is removed. The cleaned steel strip is hot-dipped.

Method and apparatus for hot-dipping steel strip

A titanium oxide film consists of a mixture of titanium monoxide (TiO), titanium dioxide (TiO.sub.2), titanium trioxide (Ti.sub.2 O.sub.3), titanium pentoxide (Ti.sub.3 O.sub.5) and other titanium oxides which are expressed as Ti.sub.n O.sub.2n-1 is an integer from 4 to 10. Average content of oxygen in the film is from 51 to 59 atom percent.

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Osaka, Japan

Yasushi Fukui