Abstract:
Carbothermic reduction of refined alumina is conducted in a reactor at temperatures in excess of 2150 -C so that no slag melt containing aluminium carbide is thermodynamically stable. A slurry of fine carbon particles in carbon-saturated aluminium is force-circulated through the metal producing reactor (1) and electrically heated in an external melt circulation loop (81) using a pumps (9) following impeller assisted drawdown (8) of fine carbon particles to maintain 5-15 volume percent solids. Thermal expansion is accommodated using snorkels immersed in slurry pools (75). Distribution of preheated solids along the length of (1) into the turbulently flowing slurry ensures high reaction intensity. Entrainment into turbulent axisymmetric jets for partial quenching of off- gases avoids accretion problems and is followed by venturi-type gas-solid contactors (19, 20). A moving packed bed pellet decomposer (17) yields a low-carbon aluminium product. Heat from the pellets is recovered in a moving bed inert gas/solid contactor (22).
Abstract:
A method of producing metals and alloys, the method comprising heating raw materials comprising at least one metal oxide, and agglomerates comprising a carbonaceous reducing agent and a cured binder to effect reduction of the metal oxide to the metal, wherein each agglomerate has at least one molded open channel, and an apparent density not greater than 99% of the apparent density of an identical agglomerate except without the channel.
Abstract:
An agglomerate, comprising alumina, carbon, and a binder for use in a vapor recovery reactor of a carbothermic alumina reduction furnace is disclosed. A method for using alumina-carbon agglomerates to capture aluminum vapor species and utilize waste heat from off-gases in a vapor recovery reactor to form a recyclable material is also disclosed. The recyclable material formed typically comprises aluminium carbide and Al-carbide containing slag, which are recycled to the carbothermic reduction furnace.
Abstract:
Die Erfindung betrifft ein Verfahren zur Reduktion und zur Zerflüssigung von präparierten metallhaltigen Erzen sowie metallhaltiger Reststoffe, zusammenfassend als Gut (8) bezeichnet. Das Gut (8) wird dabei durch Schwerkraft und/oder durch ein elektro-magnetisches Wanderfeld durch einen Körper (11) bewegt, wobei es durch ein durch eine Spulenanordnung (2) erzeugtes Magnetfeld in schwebender Position gehalten wird. Durch die Spulenanordnung (2) wird außerdem ein Wirbelstromfeld erzeugt, um eine für die Reduktion bzw. für die Verflüssigung notwendige Temperatur im Inneren des Körpers (11) zu erzeugen. Da das Gut (8) im Körper (11) schwebt, besteht kein Kontakt zwischen Gut (8) und der Körperinnenwand (10), weshalb es nicht erforderlich ist, dass der Körper (11) hochfeuerfestes Material aufweist. Erfindungsgemäß wird eine metallurgische Vorrichtung (1) bereitgestellt, die mit geringeren Kosten hergestellt werden kann und die zuverlässiger und mit geringerer Prozesszeit arbeitet, als bei Anwendung herkömmlicher Technologien bekannt.
Abstract:
The present invention relates to a process for the production of a metal or an alloy which comprises reducing a metal ore with a carbon material, where the carbon material is solid carbon produced from a carbon-containing gas.
Abstract:
The present invention provides a method of reducing metal oxide material to metal comprising the steps of forcibly circulating molten carrier material in a closed loop path serially through a charge reduction zone on one arm of the loop, a combined melt desulphurisation zone and post combustion or heating zone on the other; reducing said metal oxide to solid metal by the carbonaceous material contained within a mixed composite charge of the metal oxide, carbonaceous reductant and flux in said reduction zone, the metal oxide and carbonaceous reductant being utilised in proportions such that the carbon from the carbonaceous reductant is converted to carbon monoxide; reacting carbon monoxide with oxygen in the refining loops downstream from the reduction loop before being combusted to completion in the heating zone at the surface of the molten carrier material so that heat generated by the reaction is transferred to the molten carrier material which is circulated to the reduction zone; separating a metallised raft from said molten carrier material by projecting said metallised raft along into the first refining loop by virtue of the drag force exerted on the metallised raft by the circulating carrier material before the molten carrier material is circulated to the heating zone so that the surface of the molten carrier material which is circulated to the heating zone is substantially free of solid material.
Abstract:
A process for separating and recovering a desired metal as metal oxide from raw material is provided. The process includes placing the raw material and a reductant in a container to form a reducing microclimate within the container. A housing having an oxidizing atmosphere is heated to maintain a temperature zone within the housing at a heating temperature sufficient to expose the raw material in the container to a reaction temperature. The container containing the raw material is conveyed through the temperature zone in the housing to expose the raw material and the reductant to the reaction temperature wherein the metal oxide is reduced to a gaseous metal that exits the container. Once outside the container, the gaseous metal is exposed to the oxidizing atmosphere of the temperature zone wherein the desired metal is oxidized to metal oxide and the metal oxide is collected. In preferred embodiments, the raw material is EAF dust and the desired metal is zinc. In one specific embodiment, the process also includes maintaining a second temperature zone in the housing at a metal halide vaporization temperature, which is lower than the heating temperature. A flow of air is applied through the housing in a direction that is opposite to a direction of travel of the container during the conveying step, whereby a metal halide in the raw material is volatilized to a volatilized metal halide when the container is conveyed through the second heating zone. The volatilized metal halide is then collected.
Abstract:
The present invention relates to a process for carbothermic production of aluminum where a molten bath comprising aluminum carbide and aluminum oxide is produced in a low temperature compartment (20), and continuously flows into a high temperature compartment (3) where the aluminum carbide is reacted with alumina to produce a top aluminum layer (31), where the aluminum layer (31) forms a layer on the top of a molten slag layer and is tapped from the high temperature compartment (3) at outlet (5), and where off-gases from the two compartments are treated in reactors (10) fed by one or more columns (9, 19). Also, the present invention relates to a reaction vessel (1) in which are located the low temperature compartment (2) separated from the high temperature compartment (3) by an underflow partition wall (4). The present invention further relates to aluminum shapes such as ingots (62) formed by casting degassed aluminium from which aluminium carbide had been precipitated and filtered.