The present invention relates to techniques for producing 2024 and 7075 aluminum alloys by recycling waste aircraft aluminum alloys, which belong to technical fields for circular economy. The present invention develops techniques for obtaining the 2024 and 7075 aluminum alloys by subjecting waste aircraft aluminum alloys as raw materials to pretreatment, smelting, impurity removal, melt ingredient assay, ingredient adjustment, refining, and casting. Through utilizing the waste package aluminum alloys and the waste aluminum pop-top cans to adjust the ingredients, the waste aircraft aluminum alloys would be recycled at a lower cost without downgrading. The present invention has some advantages, such as low cost, and applicability for industrial production, as well as prominent economic benefit.

The alunite ore processing method consists of crushing, grinding and flotation of raw alunite ore. The enriched alunite ore is roasted at 520 to 620 C., the roasting time is 1 to 3 hours. The roasted alunite is leached with 5 to 20% sodium carbonate solution, which is in 100 to 110% of the stoichiometric amount required to bond the SO.sub.3 aluminum sulfate in the alunite with leaching conditions of 70-100 C. for 0.5-2.0 hours. The obtained slurry contains all of the potassium sulfate from the alunite and all of the sodium sulfate obtained from sodium carbonate. In the insoluble residue remains all aluminium oxide and residual rock. The sulfate solution is separated from the insoluble residue and is converted with potassium chloride to potassium sulphate (fertilizer) and kitchen salt. The insoluble residue is treated by the Bayer method without the use of an autoclave and results in aluminium oxide (alumina) and quartz sand.

A process for extracting values from lithium slag comprising: (a) hydrothermally treating lithium slag with an aqueous solution of an alkaline compound at selected temperature and duration; (b) performing an ion exchange step on the alkaline treated lithium slag; and (c) recovering values selected from the group consisting of aluminium compounds, silicon compounds and compounds containing silicon and aluminium.

A decoating system includes a dust cyclone and cooled conveyor. The dust cyclone is configured to receive an exhaust gas from a decoating kiln, filter organic particulate matter from the exhaust gas as dust, and discharge the dust at a discharge temperature. The cooled conveyor is configured to receive the dust from the dust cyclone and cool the dust to a dust processing temperature that is less than the spontaneous reaction temperature.

A system for processing red mud comprising: a first heating section controlled to heat red mud to a first temperature; a second heating section controlled to heat the red mud to a second temperature lower than the first temperature; a crusher configured to grind the red mud to a predetermined particle size; and one or more separators for physically extracting at least iron and aluminum from the red mud.

Systems and methods for efficiently performing rotary batch decoating can use time-offset batch reactors. A first batch reactor can operate out of phase with a second batch reactor, so that the burning of pyrolysis gases from the first reactor can be used to provide fuel to the incinerator used to heat the material in the second reactor. After the first reactor is dumped and filled with new material, the pyrolysis gases from the second reactor can be used to provide fuel to the incinerator, which heats the material in the first reactor.

Aluminum scrap having organic adhesions is processed to recover aluminum. A hearth of scrap chamber of a multi-chamber melting furnace is batchwise loaded with aluminum scrap where it is heated in low oxygen to convert the organic adhesions on the aluminum scrap into a pyrolysis gas. In a second pretreatment phase, the scrap chamber is heated to the auto-ignition temperature of the pyrolysis gas, wherein at least one air flow is provided in the scrap chamber to produce an ignitable substoichiometric pyrolysis gas/combustion air mixture which is reacted in the scrap chamber in a combustion process. The atmosphere from the scrap chamber is transferred to a post-combustion. A corresponding multi-chamber melting furnace is also provided.

A method including providing a quantity of metal, the quantity of metal being contaminated by a contaminant including a quantity of carbon; configuring a vacuum induction furnace to operate according to a set of operating parameters, the set of operating parameters being selected based on characteristics of the contaminant, the set of operating parameters including at least one of a pressure, an atmosphere composition, a pour temperature, or a hold time; charging the vacuum induction furnace with the quantity of metal; and operating the vacuum induction furnace to melt the quantity of metal in accordance with the set of operating parameters, whereby at least some of the contaminant is removed from the quantity of metal so as to provide an output metal having a concentration of carbon that is less than or equal to a concentration of carbon in the metal as cast.

The disclosure relates to a method for producing feedstock in piece form from metal, in particular aluminium and/or aluminium alloys, for a metal-casting installation, in particular aluminium-casting installation, in which scrap parts of metal, in particular of aluminium and/or aluminium alloys, are sorted on the basis of their alloying constituents and/or alloy contents and subsequently, on the basis of an alloy to be produced in the feedstock, the scrap parts are mixed into a composition having a homogeneous distribution of the alloy and fed to a press, in which the scrap parts of the composition are subjected to a pressure that compresses the scrap parts while generating a temperature, wherein, as a result of the application of pressure, the scrap parts are heated up to the transition temperature between solid and liquid of at least some of the scrap parts and/or the alloys and/or alloying constituents thereof before the feedstock is discharged in a specific geometrical form.

A system and method for recovering a high yield of low carbon ferrochrome from chromite and low carbon ferrochrome produced therefrom. A stoichiometric mixture of feed materials including scrap aluminum granules, lime, silica sand, and chromite ore are provided into a plasma arc furnace. The scrap aluminum granules are produced from used aluminum beverage containers. The feed materials are heated, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxide in the chromite to produce molten low carbon ferrochrome with molten slag floating thereon. The molten low carbon ferrochrome is extracted, solidified and granulated into granules of low carbon ferrochrome. The molten slag is extracted, solidified and granulated into granules of slag.