Abstract: Provided is a device for producing partially reduced iron, with which partially reduced iron having a prescribed reduction ratio can be produced efficiently. The present invention is equipped with: CO sensors that detect the carbon monoxide concentration in an exhaust gas; an O2 sensor that detects the oxygen concentration in an exhaust gas; an exhaust gas circulation device that adjusts the circulating amount of the exhaust gas supplied to a reduction furnace main body, and an air feed device that adjusts the amount of air that being fed; and a control device that controls these devices. The control devices on the basis of the carbon monoxide concentration in the exhaust gas as detected by the CO sensor and the oxygen concentration in the exhaust gas as detected by the O2 sensor.

Abstract: Provided is a device for producing partially reduced iron, with which partially reduced iron having a prescribed reduction ratio can be produced efficiently. The present invention is equipped with: CO sensors that detect the carbon monoxide concentration in an exhaust gas; an O2 sensor that detects the oxygen concentration in an exhaust gas; an exhaust gas circulation device that adjusts the circulating amount of the exhaust gas supplied to a reduction furnace main body, and an air feed device that adjusts the amount of air that being fed; and a control device that controls these devices. The control devices on the basis of the carbon monoxide concentration in the exhaust gas as detected by the CO sensor and the oxygen concentration in the exhaust gas as detected by the O2 sensor.

Abstract: Provided is a green pellet (10) which comprises: an inner core layer (11) containing an iron oxide-containing starting material, a carbonaceous material for reduction, and a slag-forming agent; and a coating layer (12) disposed so as to encapsulate the surface of the inner core layer (11), wherein the coating layer (12) is formed from a protective layer (12a), which is disposed so as to encapsulate the surface of the inner core layer (11) and which contains an inorganic compound (includes an alkali metal oxide) having a melting point that is 750°C. or greater but less than 1100°C., and a combustion layer (12b ), which is disposed so as to encapsulate the surface of the protective layer (12a) and which contains the carbonaceous material.

Abstract: A partially-reduced iron producing apparatus includes: an exhaust gas circulating device which supplies an oxygen-containing gas to raw-material pellets to be heated by a heat of ignition raw-material pellets, the oxygen-containing gas made by circulating part of an exhaust gas discharged from the raw-material pellets by use of the heat of the ignition raw-material pellets heated in a heating furnace and mixing the discharged exhaust gas with air; and a liquid-tar separating device which is provided in the exhaust gas circulating device and which separates a tar component in the exhaust gas from the exhaust gas as a liquid tar.

Abstract: A partially-reduced iron producing apparatus includes: a supplying device laying ignition raw-material pellets on an endless-grate; a heating furnace heating the ignition raw-material pellets; another supplying device laying the raw material pellets on the ignition raw-material pellets; and an exhaust gas circulation device supplying an oxygen-containing gas to the raw-material pellets. The oxygen containing gas is made by circulating part of an exhaust gas discharged from the raw-material pellets and mixing it with air. A partially-reduced iron is produced by thermally reducing the raw-material pellets in a bed height direction thereof through separate combustion and heating regions. The combustion region formed on an upstream side in a travelling direction of the endless grate by supplying the oxygen-containing gas having a high oxygen concentration.

Abstract: A reduction furnace includes a pellet material supplying device forming on a grate an ignition carbon material layer having a predetermined height; an ignition device; and an exhaust gas circulation device supplying an oxygen-containing gas comprising circulated exhaust gas mixed with air, to a packed bed of the pellets heated by a combustion heat of the ignition carbon material layer. A partially-reduced iron is produced by thermally reducing the pellets through a combustion region for the ignition carbon material layer and a heating region, the combustion region formed upstream in a travelling direction of the grate by supplying a gas having a high oxygen concentration, the heating region formed downstream of the combustion region by supplying a gas having a low oxygen concentration.

Abstract: A partially-reduced iron producing apparatus includes: an exhaust gas circulating device supplying an oxygen-containing gas to raw-material pellets to be heated by ignition of raw-material pellets, the oxygen-containing gas made by circulating part of an exhaust gas by use of the heat of the ignition raw-material pellets and mixing the discharged exhaust gas with air; and a liquid-tar separating device which is provided in the exhaust gas circulating device. A partially-reduced iron is produced by heating and reducing the whole of the raw-material pellets in a bed height direction thereof through a combustion region for the raw-material pellets and a heating region for the raw-material pellets, the combustion region formed on an upstream side of an endless grate by supplying the gas having a high oxygen concentration; and the heating region formed downstream of the combustion region of the endless grate by supplying the gas having a low oxygen concentration.

Abstract: The present invention relates to a method of joining a hub 11 and a shroud 12 of an impeller 10, either one of which has blades 13 integrally formed thereon, by welding. During the welding, in an upright state in which the hub 11 is placed to face a mount surface, the hub 11 and the shroud 12 are placed on top of each other to form an assembled body 10. Welding is performed on the assembled body 10 covered with a heat insulating jacket 30(a to g), the jacket 30 covering the assembled body 10 except an open region (OP) and an inflow port 14IN required for welding. When welding of one open region OP is completed, a new open region OP is formed by moving the heat insulating jacket 30 with respect to the assembled body, and then the next welding is performed.

Abstract: The present invention relates to a method of joining a hub 11 and a shroud 12 of an impeller 10, either one of which has blades 13 integrally formed thereon, by welding. During the welding, in an upright state in which the hub 11 is placed to face a mount surface, the hub 11 and the shroud 12 are placed on top of each other to form an assembled body 10. Welding is performed on the assembled body 10 covered with a heat insulating jacket 30(a to g), the jacket 30 covering the assembled body 10 except an open region (OP) and an inflow port 14IN required for welding. When welding of one open region OP is completed, a new open region OP is formed by moving the heat insulating jacket 30 with respect to the assembled body, and then the next welding is performed.

Abstract: Provided is a green pellet (10) which comprises: an inner core layer (11) containing an iron oxide-containing starting material, a carbonaceous material for reduction, and a slag-forming agent; and a coating layer (12) disposed so as to encapsulate the surface of the inner core layer (11), wherein the coating layer (12) is formed from a protective layer (12a), which is disposed so as to encapsulate the surface of the inner core layer (11) and which contains an inorganic compound (includes an alkali metal oxide) having a melting point that is 750° C. or greater but less than 1100° C., and a combustion layer (12b), which is disposed so as to encapsulate the surface of the protective layer (12a) and which contains the carbonaceous material.