Stora Kopparbergs Bergslags Aktiebolag

Asea Aktiebolag

Allmanna Svenska Elektriska Aktiebolaget

Stora Kopparbergs Bergslags Ab

Per Harald Collin

Bjorn Widell

Folke Karl Johansson

Martin Hirsch

Lothar Reh

Sune N Flink

Yngve Sundberg

The invention relates to a method of combined production of electrical energy and crude iron and provides a further improvement over a method described in U.S. Pat. No. 3,985,544, issued Oct. 12, 1976; particularly, this method finds application when particulates of .ltoreq. 1 mm in size are being used in practicing the further improved and described process.

Method for simultaneous combined production of electrical energy and

Fine-grained iron oxide reduction in a fluidized bed; a reducing agent in the form of fine-grained solid carbonaceous material containing volatile constituents is introduced into at least one zone of the fluidized bed; in said zone the volatile constituents are driven off, and a tarry material is temporarily formed on the surface of the particles of the carbonaceous material; the fine-grained iron oxide to be reduced is introduced into said zone; iron oxide particles adhere to the tarry carbonaceous particles; in this manner micro-aggregates which are especially desired are formed; but the formation of bigger aggregates is prevented.

Method of reducing finely grained material containing iron oxides in a

For the melt reduction in a DC electric arc furnace of iron oxide material of such a fine grain size that it can be blown about by the action of an electric arc, a hearth for the iron melt used, is provided with an outer wall and a roof down through which an arcing electrode extends with its tip positioned to form an arc with the melt, the electrode having a lengthwise passage through which the fine-grained oxide material, together with equally fine-grained particles of carbonaceous material, are fed to the tip. This prevents substantial loss of the materials by their being blown away from the arc. The arc, unshielded by the flow of materials, can produce from the space radiation damaging to furnace linings. To prevent the effect of such radiation, at least the electrode tip is surrounded by a coke bed floating on the melt and retained by a partition depending from the roof symmetrically around the electrode, down to a level spaced above the melt level, the lower portion of the coke bed closing the space between the partition and the melt. The partition forms an outer space within the wall and under the roof and to which the reaction gases can flow via the interface between the coke bed and the melt and possibly through the particles of coke, to this outer space, the latter having means for exhausting the gases. The coke bed permits the arc to operate while acting as a barrier against the arc radiation, while the coke bed at the same time permits the reaction gases to flow under the bed to the outer space for discharge from the apparatus, the bed shielding the furnace construction above, against the heat of the discharging gases.

Apparatus for the melt reduction of fine-grained iron oxide material

For the melt reduction of iron oxides, arcs are formed between at least three arcing electrodes in an iron melt, the electrodes being symmetrically positioned about a common vertical axis. The arcs are powered by direct current with the electrodes being cathodic and the melt anodic, and the electrodes are interspaced so closely together that the arcs, due to the direct current powering, converge and form a common focal spot at the electrodes' axis, on the melt, the spot remaining stationary and with any slag on the melt blown away so that the spot is formed by bare metal. Iron oxide material and carbonaceous material, in fine form, is fed downwardly to this spot with the reaction between the oxides and carbon occurring practically immediately.

Method and apparatus for the melt reduction of iron oxides

A method of reducing a pulverized material containing iron oxides mixed with carbonaceous material wherein: (a) a circulating fluidized bed is maintained in a vertically elongated reaction zone by supplying it with suitable quantities of pulverized material containing iron oxides, pulverized solid carbonaceous material and optionally liquid carbonaceous material, and gas containing molecular oxygen and that gas and solid material leaving the reaction zone are separated, the solid material being returned to the reaction zone; (b) the pulverized material containing iron oxides, the carbonaceous material and the gas containing molecular oxygen are supplied to an intermediate section of the reaction zone; (c) the flow of carbonaceous material fed to the bed is controlled so that there is always sufficient coke in the bed to prevent interference of the fluidization caused by sticking or agglomeration; (d) gas and solid material leaving the reaction zone are extracted from the upper part of the reaction zone, the solid material being separated from the gas and being returned to the intermediate section of the reaction zone; (e) a portion of the gaseous reaction zone exhaust, after dust separation and elimination of most of carbon dioxide and water, is fed to the lower part of the reaction zone as fluidizing and reduction gas; and (f) solid material containing completely or partially reduced iron oxides is drawn from the lower part of the reaction zone.

Method for reducing material containing iron oxides

A method for endothermic reduction of solid materials in a circulating fluid bed comprising a vertically elongated reaction zone of intermediate and lower sections separated by a transport zone, wherein due to high gas velocity therein essentially all materials entering the transport zone are transported from the lower to the intermediate section; an apparatus for carrying out such method is also disclosed.

Method for carrying out endothermic reduction processes in a

A furnace for melting solid ferrous pieces such as pig iron and steel scrap, features a combination of electric induction heating and flame heating of the pieces which are charged into the furnace hearth via a charging stack up through which the products of combustion flow from the furnace counter-current to the descending charged pieces moving downwardly through the stack. The flame heating is via burners supplied with hydrocarbon fluid fuel with oxygen proportioned for incomplete combustion, the products of combustion and unburned fuel ascending through the stack and preheating the descending charged pieces. Air is supplied to the stack to complete the combustion of the previously unburned fuel in and around the descending pieces, this being done at a level where the descending pieces have not yet reached temperatures sufficient to cause excessive oxidation of the pieces. Other details providing for effective utilization of these principles, are included in the disclosure.

Furnace for melting solid ferrous pieces

A process for the conversion of carbonaceous materials containing sulphur to an essentially sulphur-free combustible gas by gasification, comprising partially gasifying the carbonaceous material in a first circulating fluid bed by supplying to said zone adjusted streams of the carbonaceous material, finely-divided CaO-containing material and steam, separating solid materials from streams of gases and solid materials leaving said reaction zone, subjecting an adjusted fraction stream of said solid materials to separation of ashes and sulphur purification and then returning this stream to the reaction zone, transferring the rest of the solid materials to a second circulating fluid bed, wherein the solid materials by partial combustion with an adjusted stream of gases containing molecular oxygen is heated to an overtemperature which is adjusted by controlling the content of oxygen of the gas in such a way that the materials after separation from the reaction gases and recirculation to the first fluid bed satisfies the heat requirement for the gasification therein. The invention also covers an apparatus for carrying out said process.

Apparatus for and process of converting carbonaceous materials

The invention relates to a method of combined production of electrical energy and crude iron, comprising reducing iron oxides while keeping the temperature below the melting point of the crude iron during a pre-reduction and above said melting point during a final reduction. The pre-reduction is made by introducing carbonaceous material and the material containing iron oxides into a fluid bed containing solid carbonaceous material, producing reducing gases in the fluid bed by partial combustion of the carbonaceous material with air/or oxygen gas, pre-reducing the iron oxides by said reducing gases until the material has achieved a metallization degree of 30-80 %, most of the heat requirement of the pre-reduction being covered by said combustion. The pre-reduced material is finally reduced and molten by being brought into contact with carbon, and the heat requirement of this final reduction and melting process is covered by electric heating. A substantial part of the exhaust gases from the reduction operations is passed to a thermal power station to generate electrical power therein.

To reduce metal oxides to molten metal, an electrically non-conductive, annular hearth is used, the hearth being radially corrugated to form radial ridges and valleys. A circumferentially continuous coke bed forming a closed electric circuit, is formed on this bed and heated to incandescence by electric current passed through the bed in its circumferential direction, the current being either induced or applied directly. The oxides in particulated form are fed to this bed for reduction to molten metal, the metal collecting in the valleys of the hearth and thereby being prevented from forming a circumferentially continuous melt of higher electrical conductivity than the coke. Particulated coke and oxides can be fed continuously to the bed, the molten metal being then continuously tapped from the valleys of the hearth to thereby prevent the formation of a circumferentially continuous melt.

Furnace and method for reducing metal oxides to molten metal

A method for reducing iron oxide in a melt of iron by maintaining a reduction layer on the surface of the molten iron and passing the molten metal from the melt through vertical channels which communicate at the bottom of the metal melt an with a space at the top of the melt which is above that of the reduction layer so as to pass the melt including the oxide there through the reduction layer, the molten metal being lifted up through the channel by means of a gas lift pump action and heating the molten metal by inductive heating while it is flowing through the channel.

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Falun, Sweden

Per Harald Collin