A method of recovering rare earth elements from a rare earth-containing material comprises contacting the rare earth-containing material with a solution formulated and configured to dissolve rare earth elements from the rare earth-containing material and form a solution including a plurality of rare earth elements dissolved therein. The method further includes exposing the solution including the plurality of rare earth elements dissolved therein to one of a liquefied gas or a supercritical fluid to isolate the rare earth elements from each other. Related methods of removing and purifying rare earth elements from materials and phosphor lamps are also disclosed.

Systems and methods are provided for capturing CO.sub.2 from a combustion source using molten carbonate fuel cells (MCFCs). At least a portion of the anode exhaust can be recycled for use as a fuel for the combustion source. Optionally, a second portion of the anode exhaust can be recycled for use as part of an anode input stream. This can allow for a reduction in the amount of fuel cell area required for separating CO.sub.2 from the combustion source exhaust and/or modifications in how the fuel cells can be operated.

A process for producing reducing gas for use in the production of direct reduced iron (DRI) and fuel gas for use in a steel mill, including: compressing a coke oven gas (COG) stream in a compressor; passing the compressed coke oven gas stream through an activated charcoal bed to remove tars from the compressed coke oven gas stream; separating a hydrogen-rich gas stream from the compressed cleaned coke oven gas stream using a pressure swing absorption unit; providing the hydrogen-rich gas stream to a direct reduction shaft furnace as reducing gas; and providing a remaining gas stream from the pressure swing absorption unit to a steel mill as fuel gas. Both once-through and recycle options are presented. Optionally, basic oxygen furnace gas (BOFG) is added to the reducing gas.

A direct reduction process producing DRI from iron oxide particles by reduction at a about 750? C. with a reducing gas mainly H.sub.2 and CO, that also includes CO.sub.2, H.sub.20, and methane, a the reduction reactor and the top gas effluent from the reduction reaction after cooling/scrubbing is split. The resulting first top gas portion with a first hydrocarbon-containing make-up gas passes through a catalytic reformer yielding an improved hot reducing gas first effluent. The second top gas portion passes through a CO.sub.2 removal unit and then with the second hydrocarbon-containing make-up gas passes through a heater yielding a hot CO.sub.2-lean recycle reducing gas second effluent. The first and second effluents are fed to the reducing zone of the reduction reactor as the reducing gas reactant. The flow rate of at least the second of the two make-up gases is regulated to control the carbon content of the DRI produced.

The present invention concerns a method for producing carbon monoxide (CO), comprising the steps of: providing a gaseous initial input stream comprising carbon dioxide (CO2) to a plasma zone: at least partially converting said CO2 to CO by: (a) igniting a plasma in the plasma zone: (b) extracting an output stream from the plasma zone, said output stream comprising less CO2 than said first stream, and recycling said output stream as a gaseous input stream to said plasma zone and further converting CO2 to CO by performing steps (a) and (b), thereby obtaining a final output stream comprising more CO and less CO2 than the initial input stream.

Various embodiments relate to several processes that may recover commodity chemicals from an alkaline metal-air battery. In various embodiments, while the cell is operating, various side products and waste streams may be collected and processed to regain use or additional value. Various embodiments also include processes to be performed after the cell has been disassembled, and each of its electrodes have been separated such as not to be an electrical hazard. The alkaline metal battery recycling processes described herein may provide multiple forms of commodity iron, high purity transition metal ores, fluoropolymer dispersions, various carbons, commodity chemicals, and catalyst dispersions.

In various aspects, systems and methods are provided for operating a molten carbonate fuel cell assembly at increased power density. This can be accomplished in part by performing an effective amount of an endothermic reaction within the fuel cell stack in an integrated manner. This can allow for increased power density while still maintaining a desired temperature differential within the fuel cell assembly.

A method for heating a blast furnace stove includes combusting a fuel with a lower heating value (LHV) of 9 MJ/Nm.sup.3 or less in a combustion zone which is arranged in a combustion chamber in the stove, and causing the combustion gases to flow through and thereby heat refractory material in the stove. The fuel is combusted with an oxidant including at least 85% oxygen, and combustion gases are recirculated into the combustion zone for diluting the mixture of fuel and oxidant therein sufficiently for the combustion to be flameless.

Methods and systems for producing DRI utilizing a petroleum refinery bottoms (i.e. heavy fuel oil, vacuum residue, visbreaker tar, asphalt, etc.) or petroleum coke gasifier and a hot gas cleaner. Cooling of the hot synthesis gas generated by the petroleum refinery bottoms or petroleum coke gasifier to <200 C is not necessary. Rather, the synthesis gas from the petroleum refinery bottoms or petroleum coke gasifier is desulfurized and dedusted at high temperature (>350 C) using a hot gas cleaner, well known to those of ordinary skill in the art, although not in such an application. This hot gas cleaner may be high pressure or low pressure.

Apparatus for supplying blast to a blast furnace (1) having a plurality of hot blast stoves (4, 5, 6), each stove including a cold blast inlet, a fuel inlet, an air supply inlet, a hot blast outlet, and a waste gas outlet; a waste heat recovery unit (30) connected to a fuel supply, the stove fuel inlet and the cold blast inlet. The stove waste gas outlets are connected to the cold blast inlets, whereby stove waste gas from one stove (5) is supplied, via the waste heat recovery unit, as cold blast to another stove (4).