Enhanced dross feedstock

Abstract

To provide improved handling and treatment of dross from aluminum recycling such that the dross can be more easily and efficiently handled.SOLUTION: The efficiency of roasting black dross can be improved by pre-processing the black dross before roasting. The black dross can be crushed and reconstituted into pellets having internal channels. The internal channels can be filled with additives designed to fully oxidize during the dross roasting process, enabling the internal channels to be open and gas to flow therethrough during the dross roasting process. The crushed black dross can be crushed to pieces below 10 mm and screened for large pieces prior to pelletizing to ensure consistent pellets. Optionally, an eddy current separator can remove some metallic aluminum from the crushed black dross prior to the pelletizing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Application No. 62 / 867,718, entitled "ENHANCED DROSS FEEDSTOCK," filed June 27, 2019, the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002] This disclosure relates generally to metal recycling, and more specifically to the treatment and use of dross resulting from aluminum recycling. [Background technology]

[0003] The by-products of metal recycling, especially aluminum recycling, can be difficult to handle and process. For example, aluminum recycling typically produces black or white dross as a by-product of the recycling process. Black dross typically contains some aluminum, a moderate amount of aluminum oxide, and a significant proportion of salt. For example, some black dross from recycling used beverage can (UBC) stocks produces black dross containing approximately 10% aluminum, 50% salt, and 40% oxide, although other amounts may occur. White dross is a mixture of oxide and metallic aluminum and typically contains little salt. The metal from white dross is most often recovered by treating the dross with salt at high temperatures. This produces an oxide / salt by-product commonly referred to as Glauber's salt. These by-products may contain nitrides, carbides, and other materials.

[0004] By-products can be hazardous and require highly controlled transportation and disposal operations. For example, dross from aluminum recycling must be handled carefully because it can generate explosive hydrogen when wet. Current dross processing technologies generally require separate facilities, so the dross must be transported from its source to a processing facility. In some countries, regulations prohibit various handling and disposal of such materials. Current dross processing technologies focus on recovering metals (e.g., aluminum) through heating and melting, and recovering salts through leaching and evaporation. These current technologies rely on high-power discharges, such as heating batches of white dross to remove metals, using large amounts of water and energy to leach salts from the dross or Glauber's salt, and then evaporating the water to recover the salt. The water and energy used to leach salts from the dross are so significant that certain current white dross processing technologies are specifically focused on salt-free processes to eliminate the need for salt recovery in a later step. Additionally, leaching of salts from dross can produce significant harmful, toxic, and / or reactive gases (e.g., H2S, PH3, NH3, H2 / CH4) that require controlled collection and destruction.

[0005] Therefore, it is desirable to improve the handling and processing of dross derived from aluminum recycling so that the components of the dross can be more easily and efficiently recovered and so that the dross can be handled more easily and efficiently. Summary of the Invention

[0006] The term "embodiments" and similar terms are intended to broadly refer to all of the subject matter of this disclosure and the following claims. Statements containing these terms should be understood neither to limit the subject matter described herein nor to limit the meaning or scope of the following claims. The embodiments of the disclosure covered herein are defined by the following claims, not this Summary. This Summary is a broad overview of various aspects of the disclosure and introduces some of the concepts that are further described in the Detailed Description section below. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. This subject matter should be understood by reference to the entire specification of this disclosure, any or all drawings, and appropriate portions of each claim.

[0007] In various examples, a method for pre-treating dross is provided. The method can include receiving dross pieces, breaking the dross pieces into dross particles having a diameter of 10 mm or less, and agglomerating the dross particles into pellets. The pellets can include channels when heated to a temperature of 800°C or greater.

[0008] In various examples, a method for treating metal recycling by-products is provided. The method can include providing dross pellets. Each of the dross pellets can include dross and an additive selected to oxidize or decompose at a channel exposure temperature of 800°C or less. The additive can be disposed within the pellet and expose channels in the pellet upon oxidation. The method can further include heating the dross pellets to a temperature equal to or greater than the channel exposure temperature. The method can further include oxidizing or decomposing the additive to expose channels in each pellet. The channels in the pellet can allow gas to enter and pass through the pellet. The method can further include maintaining the dross pellets at a temperature to perform heat treatment of the dross pellets.

[0009] In various examples, a reconstituted metal recycling by-product is provided. The reconstituted metal recycling by-product can include dross and an additive. The dross can include aluminum oxide. The additive can be selected to oxidize or decompose at a temperature of 800°C or less. The dross and additive can be agglomerated together into a pellet. The additive can be disposed within the pellet such that one or more channels through the pellet are exposed upon oxidation of the additive.

[0010] The various embodiments described herein may include additional systems, methods, features, and advantages that may not necessarily be expressly disclosed herein, but will become apparent to one of ordinary skill in the art upon review of the following detailed description and the accompanying drawings. It is intended that all such systems, methods, features, and advantages be included within this disclosure and protected by the accompanying claims.

[0011] This specification makes reference to the following accompanying figures, in which the use of like reference numbers in different figures is intended to illustrate like or similar components. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a dross heat treatment system according to certain aspects of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of a dross pelletizing system according to certain aspects of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of a pellet of dross being heated, according to certain aspects of the present disclosure. [Figure 4] 1 is a flowchart illustrating a process for producing dross pellets, according to certain aspects of the present disclosure. [Figure 5] 1 is a flow chart illustrating a process for treating dross pellets according to certain aspects of the present disclosure. [Figure 6] FIG. 1 is a schematic diagram illustrating a system for extracting salt from dross, according to certain aspects of the present disclosure. [Figure 6A] FIG. 1 is a schematic diagram illustrating another system for extracting salt from dross, according to certain aspects of the present disclosure. [Figure 7] 1 is a flowchart illustrating a process for extracting salt from dross, according to certain embodiments of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram illustrating a two-stage process for heat treating dross according to certain embodiments of the present disclosure. [Figure 9] FIG. 1 is a schematic diagram illustrating a single vessel, two-stage process for heat treating dross according to certain embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Certain aspects and features of the present disclosure relate to techniques for improving the efficiency of roasted dross, such as black dross or mirabilite (e.g., white dross reacted with a salt flux), by pretreating the dross before roasting it to extract aluminum and / or salt. The dross can be disintegrated (e.g., ground) and reconstituted into pellets with internal channels. The internal channels can be filled with an additive designed to fully oxidize during the dross-roasting process, opening the internal channels during the dross-roasting process to allow gas to flow therethrough. The disintegrated dross can be broken down into fragments less than 10 mm, and larger fragments can be screened prior to pelletizing to ensure consistent pellets. Optionally, an eddy current separator and / or other suitable means can be used to remove some metallic aluminum from the disintegrated dross prior to pelletizing.

[0014] Metal recycling, such as aluminum recycling, can produce secondary metals (e.g., secondary aluminum) and various recycling by-products. For example, in the aluminum recycling process, the recycling by-products can be multiple types of dross or a mixture of metallic aluminum and aluminum oxide. In some cases, other materials in the recycled aluminum may contain contaminants or salts that may ultimately be present in the dross. Various types of dross can exist, such as white dross and black dross. White dross is primarily composed of aluminum and aluminum oxide, while black dross additionally contains salts. The terms white and black, when used with respect to dross, refer to the type of dross and not necessarily the physical color of the dross. In some cases, the processing of white dross can include combining the white dross with salt to facilitate the extraction of secondary metals.

[0015] Black dross is a common by-product of recycling used beverage can (UBC) stock, where approximately 2% by weight of salt is used to remove impurities and oxides from the aluminum in the UBC stock. The recycling process for UBC stock produces black dross balls or chunks of various sizes, on the order of tens of millimeters (e.g., 25 mm) in diameter. These black dross balls typically contain approximately 10% aluminum, 50% salt, 40% oxides, and additional contaminants by weight.

[0016] White dross is a common by-product of many other types of aluminum recycling processes. White dross can contain significant amounts of aluminum that can be removed by further processing by contacting the white dross with salt to produce Glauber's salt. As used herein, the general term dross includes Glauber's salt produced from combining white dross with salt.

[0017] It has been found, for example from recycling UBC, that black dross in its original form can retain up to about 4% by weight of carbon even after heat treatment. Generally, heat treatment of original black dross can form a layered ball with an outermost layer covered with complex oxides and an innermost layer containing non-oxidized carbon and other compounds. It has been determined that a larger surface area to volume ratio may be desirable to ensure that more of the residual carbon in the black dross reacts with oxygen.

[0018] Grinding the black dross prior to heat treatment can be potentially problematic due, at least in part, to the fact that the black dross fines are difficult to handle and can be entrained in gases exhausted from a reaction vessel (e.g., a rotary kiln). As described herein, when salt vapor is collected from the reaction vessel, the black dross fines can be entrained in the exhaust gases and potentially contaminate the salt vapor.

[0019] To avoid problems with fines in the black dross, disintegrated black dross (e.g., disintegrated by crushing or any other suitable technique) can be agglomerated into pellets. In some cases, the pellets can have a shape tailored to achieve the desired heat treatment. For example, the pellets can have channels throughout, through which oxygen passes and from which saline vapor can exit. In some cases, the channels can run all the way through the pellet, but this is not always necessary. In some cases, the channels can be single-ended, extending from the surface of the pellet partially into the pellet. The pellets can be formed by pelletizing, compacting, or any other agglomeration technique. In some cases, techniques that create inherent channels can be used to form the pellets. In some cases, the fines in the black dross can be mixed with additives before agglomeration, so that the additives form channel precursors in the pellets. Upon oxidation, the additives can decompose, leaving voids that form or expose channels in the pellets. The additives can be selected to oxidize, volatilize, or otherwise decompose at a temperature low enough to expose the channels by the time the heat treatment temperature for processing the black dross is reached. For example, an additive can be selected that oxidizes at temperatures below about 500°C, 600°C, 700°C, or 800°C, or between about 500°C and 800°C. The temperature at which the additive oxidizes, volatilizes, or otherwise decomposes to expose the channels may be referred to as the channel exposure temperature. Thus, the pellet will have channels when heated to a temperature above the channel exposure temperature. For example, the pellet may have channels when heated to a temperature above 800°C, including an additive that oxidizes at temperatures below 500°C, as compared to an additive that oxidizes at temperatures below 800°C.

[0020] In some cases, the crushed black dross may form fine particles with diameters of about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, or 2 mm or less, or about 50 micrometers, 40 micrometers, 30 micrometers, 20 micrometers, 10 micrometers, or 5 micrometers or more, at the upper end of the range. In some cases, an eddy current separator can be used to remove excess aluminum metal from the black dross fines. In some cases, the black dross fines can be screened to remove larger particles, which can be diverted for further cracking or sent for heat treatment.

[0021] In some cases, the agglomeration process may result in black dross pellets with consistent sizes, such as pellets with diameters (e.g., maximum pellet diameter or average pellet diameter) between 5 mm and 50 mm, between 10 mm and 50 mm, between 10 mm and 40 mm, between 10 mm and 30 mm, between 10 mm and 20 mm, between 12 mm and 18 mm, or between 14 mm and 16 mm. In some cases, pellet-to-pellet variations may be less than about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1 mm. Consistent pellet size facilitates accurate estimation of heat treatment times.

[0022] In some cases, the additive may include waste materials from other industries. For example, the additive may include one or more of automotive shredder residues, post-consumer scrap (e.g., shredded plastic bottles, or agricultural by-products such as corn silk, wheat husks, straw, and rice husks), textile residues, carpet residues, UBC decorator dust, or other such products. In some cases, the additive may be selected to provide some permeability to the pellets at high temperatures (e.g., above 500°C). In some cases, the additive may further include a fuel additive selected to provide a fuel to assist in generating heat within the reaction vessel. In some cases, the additive may also be selected to provide a fuel to improve the permeability of the pellets at high temperatures.

[0023] In some cases, the agglomerated pellets may be generally spheroidal in shape, but need not be, and other regular or irregular shapes may be utilized. In some cases, the pellets may have smooth or rough surfaces. In some cases, the pellets may be further pre-treated to modify the physical shape of the pellets and promote their permeability to gases.

[0024] In some cases, black dross pellets prepared as described herein can improve the efficiency and speed of salt extraction. In some cases, black dross pellets prepared as described herein can improve the oxidation of residual carbon, residual metallic aluminum, and / or other residual compounds. In some cases, black dross pellets can be used in combination with a reaction vessel designed to maintain an oxidizing environment.

[0025] In some cases, salt can be extracted from salt-containing dross by heat treatment. Traditionally, heat treatment of dross is carried out at temperatures well below 1200°C. However, by enabling or facilitating the reaction vessel to reach temperatures sufficient to vaporize the salt (e.g., above 1200°C), the salt evaporates as a salt-containing vapor and can be directed out of the reaction chamber through a gas outlet or similar. In some cases, the reaction vessel can be enabled or facilitated to reach temperatures above the boiling point of the salt in the dross (e.g., 1416°C for KCl or 1450°C for NaCl), increasing the rate at which the salt evaporates as a salt-containing vapor and is directed out of the reaction chamber. In some cases, the salt can evaporate even more slowly at temperatures close to or below the salt's boiling point. In some cases, the gas outlet also functions as a material inlet. Reaction vessels may be capable of supporting temperatures up to 1200°C to 1600°C, but these temperature ranges have not previously been commonly used in the aluminum industry. The dross can be maintained at these elevated temperatures until about 95%, 99%, 99.9%, or other relevant amounts of salt in the dross have evaporated. In some cases, the dross can be maintained at these elevated temperatures for about 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150 minutes. In some cases, such as in the case of small, permeable dross, the dross can be maintained at these elevated temperatures for about 10, 15, 20, 25, or 30 minutes. In some cases, the use of pelletized dross can facilitate oxidation of residual compounds within the dross and can facilitate reaching and / or maintaining these high temperatures simply by adding oxygen to the reaction vessel (e.g., without providing heat to the reaction vessel via a separate heat source, such as an oxy-fuel burner).

[0026] The salt-containing vapors exiting the reaction vessel may be collected and condensed into salt, which may be collected and optionally recycled for further processing of dross (e.g., white dross) or UBC (e.g., in a sidewell furnace).

[0027] In some cases, maintaining these high temperatures necessary to extract salt from the dross via the evaporative route results in the unexpected formation of a continuous, dense layer of oxide that adheres to the interior refractory surfaces of the reaction vessel. While this oxide layer can be periodically removed (e.g., to avoid loss of reactor volume), its presence provides some protection to the underlying refractory from abrasive wear, thermal shock, and chemical attack, thereby extending the life of the reaction vessel. Surprisingly, maintaining these high temperatures necessary to extract salt from the dross via the evaporative route removes aluminum nitride, thus enabling more efficient recycling of certain dross or dross treatment processes that have relatively high amounts of aluminum nitride.

[0028] In some cases, a two-stage dross treatment process can be performed. In the first stage, the white dross is contacted with salt at a first temperature to recover metals and produce Glauber's salt as a by-product. In the second stage, the Glauber's salt can be heat-treated at a second temperature sufficient to evaporate the salt (e.g., above 1200°C, or in some cases near or above the boiling point of the salt) to produce a salt-containing vapor for collection and condensation into salt. In some cases, the salt-containing vapor and / or salt can be temporarily stored and reused to subsequently process additional white dross. In some cases, the amount of salt can be increased by blending existing black dross with the white dross and / or Glauber's salt prior to the second stage. In some cases, the second stage can include oxidation of residual compounds, such as residual metals, in the dross.

[0029] In some cases, each stage of a two-stage dross treatment process can occur in the same vessel, but this need not always be the case. When a single vessel is used, the residual heat remaining after the removal of inert oxides after the second stage can be used to begin heating new white dross in a subsequent treatment process. Thus, a two-stage dross treatment process can involve the reuse of salt and heat energy between the second stage of the treatment process and the first stage of the subsequent treatment process.

[0030] In some cases, a two-stage dross treatment process can facilitate the recycling of lower-grade scrap (such as thermally broken material). In such cases, the white dross fed to the reactor comes from melting the scrap inside the reactor. In such cases, the scrap can be melted to remove secondary aluminum, salt can be added to create Glauber's salt, more secondary aluminum can be removed, and more heat and oxygen can be applied to evaporate the salt and produce an inert oxide residue.

[0031] In some cases, organic-rich materials can be added to provide some of the energy needed to achieve high temperatures in the second stage of a two-stage dross treatment process.

[0032] These illustrative examples are provided to introduce the reader to the general subject matter discussed herein and are not intended to limit the scope of the disclosed concepts. The following section describes various additional features and examples with reference to the drawings, in which like numerals indicate like elements, and directional descriptions are used to describe exemplary embodiments, but as with the exemplary embodiments, should not be used to limit the present disclosure. Elements contained in the figures herein may not be drawn to scale.

[0033] FIG. 1 is a schematic diagram of a dross heat treatment system 100 according to certain embodiments of the present disclosure. The system 100 may include a reaction vessel 102 in which heat treatment of the dross can occur. The reaction vessel 102 may be a rotary kiln, although any other suitable reaction vessel may be used. A dross supply source 104 may be used to supply dross (e.g., white dross, black dross, or Glauber's salt) to the reaction vessel 102. The reaction vessel 102 may be supplied with initial heat from a heat source 106, such as an oxy-fuel burner. While heat treatment is in progress, heat may be increased and / or maintained within the reaction vessel 102 by the addition of oxygen, such as via an optional oxygen inlet 107 or the heat source 106 (e.g., when the heat source 106 is used in a non-heated configuration to supply oxygen to the reaction vessel 102).

[0034] In some cases, controller 114 may be coupled to heat source 106 and / or oxygen inlet 107 to control the temperature inside reaction vessel 102. Controller 114 may be coupled to a temperature sensor positioned to read the temperature inside reaction vessel 102.

[0035] During heat treatment, combustion gases may be exhausted from the reaction vessel 102 through a gas outlet 108 . In some cases, the gas outlet 108 may be a port in the reaction vessel 102 through which dross is fed into the reaction vessel 102 .

[0036] In some cases, an optional salt source 112 can provide salt to the reaction vessel 102, such as in the processing of white dross.

[0037] In some cases, a salt collector 110 may be coupled to the gas outlet 108 to receive the salt-laden vapor and collect salt from the salt-laden vapor (e.g., by condensation of the salt-laden vapor). In some cases, the salt collector 110 may be coupled to the salt source 112 to replenish the salt source 112 by extracting salt from dross inside the reaction vessel 102. In some cases, an optional sensor 116 (e.g., an optical sensor) may be coupled to the salt collector 110 and / or the gas outlet 108 to detect the concentration of salt in the salt-laden vapor (e.g., by optical inspection of the opacity of the salt-laden vapor). The sensor 116 may be coupled to the controller 114 to provide feedback for controlling the temperature of the reaction vessel 102 in response to changes in the salt concentration of the salt-laden vapor. For example, if the salt concentration of the salt-containing vapor drops below a threshold value, it can be determined that at least 95%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9% or other relevant amount of salt has been extracted from the dross inside the reaction vessel 102, and the controller 114 can control the heat source 106 and / or the oxygen inlet 107 to reduce the temperature inside the reaction vessel 102.

[0038] Although the system 100 can be used with any suitable metal, the system 100 can be advantageously used with dross obtained from aluminum recycling.

[0039] FIG. 2 is a schematic diagram of a dross pelletizing system 200 according to certain embodiments of the present disclosure. The dross pieces 218 can be spherical or other shapes and can include oxides (e.g., aluminum oxide) and other materials, such as metals (e.g., aluminum metal) and salts. The dross pieces 218 can have inconsistent sizes, such as sizes ranging from 10 mm to 50 mm in diameter, although pieces of other sizes may exist. The dross pieces 218 can be introduced into a dross crusher 220, which can break the dross pieces 218 into dross particles 222 (e.g., dross fines). The dross particles 222 can have diameters of 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1 mm or less. The dross particles 222 can be mixed with additives from an additive supply 224 and then introduced into an agglomerator 526. The agglomerator 526 may be a pelletizer or other suitable device for converting the dross particles 222 and additives into dross pellets 228. The dross pellets 228 may have a relatively uniform size, on the order of 10 mm to 20 mm in diameter. In some cases, the pelletizer may be an extrusion pelletizer designed to produce extruded pellets having a rectangular or elongated shape. As used herein, references to the diameter of a rectangular or elongated shape may refer to the maximum or average diameter of the cross-section of the rectangular or elongated shape or the maximum or average length of the rectangular or elongated shape. In some cases, the length-to-diameter ratio of the pellets may be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0.

[0040] The ratio of additive and dross particles 222 can be controlled to achieve a desired permeability of the resulting dross pellet 228 when the dross pellet 228 is heated to a channel exposure temperature (e.g., a temperature at which the additive oxidizes and exposes the channels within the dross pellet 228).

[0041] 3 is a schematic illustration of a dross pellet 328 being heated according to certain embodiments of the present disclosure. The dross pellet 328 can be the dross pellet 228 from FIG. 2. The dross pellet 328 can include dross impregnated with an additive. The additive can establish channel precursors 330 within the pellet 328.

[0042] After heating the pellet 328 to the channel exposure temperature for a sufficient time, the additive may oxidize, volatilize, or otherwise decompose. The resulting channeled pellet 332 may include a channel 334 therethrough. The channel 334 may pass through the channeled pellet 332 in any direction, although in some cases the channel 334 may not extend all the way through the channeled pellet 332 (e.g., to achieve a single-ended channel 334). In some cases, the channel 334 may be surrounded by dross material of the channeled pellet 332 (e.g., forming a void through the channeled pellet 332). However, in some cases, the channels 334 may be formed entirely in the surface of the channeled pellet 332, such as in the form of depressions in the surface.

[0043] The channels 334 of the channeled pellet 332 can effectively increase the surface area to volume ratio of the pellet, allowing oxygen to more effectively permeate the pellet and saline vapor to more effectively exit the pellet.

[0044] 4 is a flow chart illustrating a process 400 for producing dross pellets according to certain embodiments of the present disclosure. Process 400 can be used to produce dross pellets 228 or dross pellets 328 of FIGS. 2 or 3, respectively.

[0045] Dross pieces can be received at block 402. The dross pieces can be broken down at block 404. Breaking down can be achieved by crushing, grinding, or otherwise interacting with the dross pieces to reduce their size to dross particles having diameters of 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1 mm or less.

[0046] In optional block 406, metallic aluminum may be extracted from the dross particles (e.g., crushed or crushed dross pieces), for example, using an eddy current separator or by any suitable means for extracting metallic aluminum from the dross particles.

[0047] At optional block 408, the dross particles can be screened for size. Screening the dross particles can include separating out oversized particles. Optionally, the oversized particles can be redirected back for further disintegration at block 404. Optionally, the oversized particles can be fed forward and heat treated at block 412.

[0048] In block 410, the dross particles may be agglomerated (e.g., reconstituted) into pellets. Agglomerating the dross particles into pellets may occur by pelletizing, compacting, or any other suitable technique for producing pellets. Optionally, an additive may be provided in block 414 and used during agglomeration in block 410 to produce pellets comprised of the dross particles and the additive. The amount and / or type of additive may be controlled to achieve a desired permeability of the resulting pellets.

[0049] At block 412, the dross pellets may be heat-treated. Heat-treating the dross pellets may include heating the dross pellets to extract compounds such as metals and salts. The heat-treating may additionally or alternatively provide energy to oxidize any remaining metals and vaporize salts. In some cases, the heat-treating at block 412 may include only the pellets agglomerated at block 410. In some cases, the heat-treating at block 412 may additionally or alternatively include the forward-fed oversized particles from screening at block 408. For example, at least some of the forward-fed oversized particles may be large enough to avoid becoming airborne fines that could contaminate the exhaust stream during heat-treating at block 412, and / or may be small enough to facilitate extraction by heat-treating at block 412 without undergoing the intervening operations at blocks 410 and / or 412 in conjunction with agglomeration with other dross particles and / or additives.

[0050] FIG. 5 is a flowchart illustrating a process 500 for treating dross pellets according to certain embodiments of the present disclosure. At block 502, dross pellets can be received. The dross pellets can include additives in the form of channel precursors. At block 504, the dross pellets can be heated to or above a channel exposure temperature. In some cases, the channel exposure temperature is at or about 500°C. In some cases, the channel exposure temperature is below 800°C, 700°C, 600°C, or 500°C, or between 500°C and 800°C or lower. Heating the dross pellets at block 504 can oxidize, volatilize, or otherwise decompose additives in the dross pellets, thereby exposing channels within the dross pellets. At block 506, the dross pellets can continue to be heated to heat-treat the dross pellets. In some cases, heat-treating the dross pellets at block 506 can include evaporating salt from the dross pellets at block 508. In some cases, evaporating salt from the dross pellets at block 508 may include passing saline vapor outside the channels of the dross pellets.

[0051] 6 is a schematic diagram illustrating a system 600 for extracting salt 650 from dross 628, according to certain embodiments of the present disclosure. The dross 628 may be the dross pellets 228 or the dross pellets 328 of FIGS. 2 or 3, respectively. The system 600 may include a reaction vessel 602. The reaction vessel 602 may be the reaction vessel 102 of FIG. 1.

[0052] Dross 628 (e.g., black dross or Glauber's salt) can be introduced into the reaction vessel 602 via a feed chute 640. A heat supply 606 can supply heated gas and optionally oxygen to the reaction vessel 602 during the treatment process. Optionally, the reaction vessel 602 can rotate to tumble the dross 628. After heating to a sufficient temperature to vaporize the salt (e.g., above 1200°C, or near or above the boiling point of the salt), the salt within the dross 628 can vaporize as salt-containing vapor 636.

[0053] Gas within the reaction chamber 602 can flow in a direction 638, carrying salt-laden vapor 636 out of a gas outlet 608. The salt-laden vapor 636 can be captured in a salt collector 610. The salt collector 610 can include a hood 642 for collecting the salt-laden vapor 636, a condenser 644 for condensing the salt-laden vapor 636 into salt 650, and a salt collection chamber 646 for storing the collected salt 650. In some cases, condensation of the salt-laden vapor can be achieved or facilitated by the entry of air and / or water (e.g., water spray) into the salt collector 610, such as through an inlet 643 coupled to or included in the condenser 644. In some cases, the condenser 644 can cool the salt-laden vapor 636 into liquid droplets, which can then be captured and converted into a solid. In some cases, the condenser 644 can cool the salt-laden vapor 636 directly into a solid without intermediate liquid droplet capture. In some cases, an optional feed path 648 can redirect the collected salt 650 to the reaction chamber 602 (e.g., via the feed chute 640). In some cases, the salt collector 610 can include an additional outlet 652 for exhausting gases other than the salt fumes 636.

[0054] FIG. 6A is a schematic diagram illustrating another system 600A for extracting salt 650 from dross, according to certain embodiments of the present disclosure. The system 600A illustrated in FIG. 6A can include elements already described with respect to the system 600 illustrated in FIG. 6. The system 600A illustrated in FIG. 6A differs from the system 600 illustrated in FIG. 6 with respect to a salt collector 610A. In the salt collector 610A, salt-laden vapor 636 collected by a hood 642 can be converted into a liquid salt mist 641 by mixing with water and / or air introduced through a water and / or air inlet 643. A bed of demister media 645 can be positioned in the path of the liquid salt mist 641 to induce condensation or otherwise coalesce the liquid salt mist 641 into droplets 647 that can fall and be collected as a bath of liquid salt inside a reservoir 649. One suitable choice for demister media 645 can be flat alumina spheres, although other types of media can be utilized. Demister media 645 can remove salt from the exhaust stream, which can be directed out exhaust 651 of salt collector 610A. Optionally, dilution inlet 653 can introduce additional air into the exhaust stream for further dilution of particles, for example, before the exhaust stream is further directed through a fan and / or baghouse.

[0055] In some cases, the temperature can be monitored and / or adjusted to promote conditions for coalescence of the droplets 647. The temperature at a reference point 655 downstream of the demister medium 645 can be measured by a suitable temperature sensor and can provide input to adjust the amount of water and / or air introduced through the water and / or air inlet 643. For example, an increase in the introduced air and / or water can be induced to decrease the downstream temperature, or a decrease in the introduced air and / or water can be induced to increase the downstream temperature. As an illustrative example, the water and / or air introduced through the water and / or air inlet 643 may be adjusted to target a downstream temperature of 800°C at reference point 655 and / or an input temperature of 850°C adjacent the water and / or air inlet 643.

[0056] Various elements can be included to process the salt 650 recovered from the liquid salt bath contained in reservoir 649. For example, the salt 650 recovered from the salt bath can be transported by a salt caster 657. In some cases, the recovered salt 650 can be introduced to a cooler 659 and / or a crusher 661. In some cases, an optional feed path 648 can redirect the recovered salt 650 (e.g., in a liquid or solid state) back into reaction chamber 602 (e.g., via feed chute 640).

[0057] Figure 7 is a flow chart illustrating a process 700 for extracting salt from dross according to certain embodiments of the present disclosure. Process 700 may occur using system 600 of Figure 6. Process 700 may occur using dross pellets 228 and 328 of Figures 2 and 3, respectively.

[0058] At block 702, the reactor vessel may be filled with dross (e.g., dross pellets). In some cases, filling the vessel with dross may include dumping the dross into the reactor vessel. In some cases, filling the vessel with dross may include generating dross within the reactor vessel through melting scrap metal.

[0059] In some cases, the dross can include white dross, and further actions can be performed to produce Glauber's salt and extract metals from the white dross. At optional block 704, salt can be added to the white dross. At optional block 706, the white dross can be contacted with the salt at a first temperature. This contact and heating can facilitate the extraction of metals from the white dross and can promote the production of Glauber's salt.

[0060] At block 708, the dross (e.g., black dross or Glauber's salt) may be heated to a temperature high enough to vaporize the salt (e.g., 1200°C). In some cases, the dross may be heated to a temperature at or above the boiling point of the salt within the dross. Heating the dross may include providing heat from a heat source (e.g., an oxygen-fuel burner) or providing oxygen to promote oxidation of fuel (e.g., residual carbon) within the reaction vessel. At block 710, the salt may be allowed to vaporize as a salt-containing vapor. In some cases, blocks 708 and / or 710 may occur for a period of time sufficient to vaporize a desired amount of salt (e.g., 95%, 99%, or 99.9%) from the dross. At block 712, the salt-containing vapor may be directed to a gas outlet. At block 714, the salt-containing vapor may be obtained. At block 716, the salt-containing vapor may be condensed into salt (e.g., solid salt or liquid salt). In some cases, the salt recovered in block 716 may be reused in subsequent block 704 to provide salt for subsequent white dross. In some cases, the salt recovered in block 716 may be reused for purposes other than subsequent production of Glauber's salt. For example, in some cases, the salt recovered in block 716 may be used to facilitate melting of scrap metal.

[0061] In some cases, the salt-laden vapor can be measured at optional block 718 to obtain a measurement of the salt concentration of the salt-laden vapor. Based on the measurement at block 718, a decision can be made to stop heating the dross and evaporating the salt at blocks 708 and 710. In some cases, this decision can be related to evaporating a desired amount of salt, as determined by the measurement at block 718.

[0062] Optionally, additional black dross can be added to the reaction vessel at optional block 720. The additional black dross may allow for greater amounts of salt to be evaporated and recovered at blocks 710, 712, 714, and 716. Optionally, adding black dross at block 720 may improve the efficiency of heat treating the subsequent white dross.

[0063] Results from one exemplary set of tests are shown in the graph below. In these test runs, the dross samples used had an initial salinity level of approximately 50% and were subjected to the temperatures and timings shown to obtain the measured percentages of salt and residual chloride removed. These results demonstrate that by operating at high temperatures (e.g., above 1200°C, or above the boiling point of the salt, or below but near this point), residual chloride salts can be reduced by greater than 99%, and the resulting calcined oxide residue is non-reactive, based on the Toxicity Characteristic Leach Procedure (TCLP) criteria established by the U.S. Environmental Protection Agency (EPA). [Table 1]

[0064] FIG. 8 is a schematic diagram illustrating a two-stage process 800 for heat treating dross according to certain embodiments of the present disclosure. In the first stage, white dross can be combined with salt in a reaction vessel and heated to a first temperature (e.g., at or about 800°C) to extract metals and produce Glauber's salt. In the second stage, the Glauber's salt and optional black dross can be heated in a reaction vessel (e.g., the same reaction vessel or a different reaction vessel) to a second temperature high enough to extract the salt as a salt-containing vapor to an inert oxide. In some cases, the second temperature is about 1200°C or higher. In some cases, the second temperature is above the boiling point of the salt (e.g., about 1500°C or higher). The extracted salt can be recycled to the first stage for subsequent processing.

[0065] FIG. 9 is a schematic diagram illustrating a single-vessel, two-stage process 900 for heat-treating dross according to certain embodiments of the present disclosure. Process 900 can be the same as process 800, but specifically performed in a single vessel. In the first stage, white dross can be combined with salt in a reaction vessel and heated to a first temperature (e.g., 800°C or about 800°C) to extract metals and produce Glauber's salt. In the second stage, the Glauber's salt inside the reaction vessel can be further heated to a second temperature (e.g., 1200°C or higher) high enough to extract the salt as a salt-containing vapor and discharge salt-free oxides. In some cases, the second temperature is above the boiling point of the salt (e.g., about 1500°C or higher). In some cases, black dross can be optionally added to the reaction vessel between the first and second stages. The salt extracted in the second stage can be reused in the first stage of subsequent processing.

[0066] The foregoing description of embodiments, including the illustrated embodiment, has been presented only for purposes of illustration and description and is not intended to be exhaustive or limited to the precise form disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art.

[0067] As used hereinafter, any reference to a series of examples should be understood as a reference to each of those examples separately (e.g., "Examples 1 through 4" should be understood as "Examples 1, 2, 3, or 4").

[0068] Example 1 is a method for pretreating dross, comprising receiving dross pieces, disintegrating the dross pieces into dross particles having a diameter of 10 mm or less, and agglomerating the dross particles into pellets, wherein the pellets comprise channels when heated to a temperature of 800° C. or greater. In some cases, the pellets comprise channels when heated to a temperature of 500° C. or greater.

[0069] Example 2 is the method of example(s) 1, further comprising mixing the dross particles with an additive selected to oxidize or otherwise decompose at a temperature of 800° C. or less, wherein the oxidation or decomposition of the additive promotes exposure of the channels in the pellet.

[0070] Example 3 is the method of example(s) 2, wherein the additive comprises post-consumer scrap or other industrial waste.

[0071] Example 4 is the method of example(s) 1-3, further comprising extracting metallic aluminum from the dross particles using an eddy current separator before agglomerating the dross particles.

[0072] Example 5 is the method of example(s) 1-4, further comprising screening the dross particles before agglomerating the dross particles, wherein the screening comprises removing large dross particles.

[0073] Example 6 is the method of example(s) 5, wherein removing large dross particles includes directing the large dross particles to further disintegrate.

[0074] Example 7 is the method of example(s) 5, wherein removing large dross particles includes directing the large dross particles to heat treatment.

[0075] Example 8 is the method of example(s) 1-7, further comprising mixing the dross particles with a fuel additive, the fuel additive selected to facilitate fueling a dross processing reaction.

[0076] Example 9 is the method of any one of examples 1 to 8, wherein the pellets each have an average diameter in the range of 5 mm to 50 mm.

[0077] Example 10 is the method of any one of examples 1-9, wherein the dross pieces comprise aluminum oxide and salt.

[0078] Example 11 is a method for treating metal recycling by-products, comprising: providing dross pellets, each of the dross pellets comprising dross and an additive selected to oxidize or decompose at a channel exposure temperature of 800°C or less, the additive being disposed within the pellet and exposing channels of the pellet upon oxidation; heating the dross pellets to a temperature equal to or greater than the channel exposure temperature to expose the channels of each pellet and oxidizing or decomposing the additive, the channels of the pellet allowing gas to enter and pass through the pellet; and maintaining the dross pellets at the temperature to heat-treat the dross pellets. In some cases, the pellet heating of the dross can be at a temperature of 500°C or less, or 800°C or less.

[0079] Example 12 is the method of example(s) 11, wherein performing the heat treatment comprises evaporating salt from the dross pellets.

[0080] Example 13 is the method of example(s) 11 or 12, wherein the additive comprises post-consumer scrap or other industrial waste.

[0081] Example 14 is the method of example(s) 11-13, wherein the dross pellets further comprise a fuel additive selected to facilitate fueling the thermal treatment.

[0082] Example 15 is the method of example(s) 11-14, wherein each of the dross pellets has an average diameter in the range of 5 mm to 50 mm.

[0083] Example 16 is the method of example(s) 11-15, further comprising removing the treated dross pellets after heat treating the dross pellets, wherein the treated dross pellets have a carbon content of 1 wt% or less.

[0084] Example 17 is a reconstituted metal recycling by-product comprising dross, the dross comprising aluminum oxide, and an additive selected to oxidize or decompose at a temperature of 800°C or less, wherein the dross and the additive together agglomerate into a pellet, and the additive is disposed within the pellet such that one or more channels through the pellet are exposed upon oxidation of the additive.

[0085] Example 18 is the reconstituted metal recycling by-product of example(s) 17, wherein the additive comprises post-consumer scrap or other industrially derived waste.

[0086] Example 19 is the reconstituted metal recycling by-product of example(s) 17 or 18, wherein the dross of the pellets comprises agglomerated dross particles, each having an average diameter of 10 mm or less.

[0087] Example 20 is the reconstituted metal recycling by-product of example(s) 17-19, further comprising a fuel additive, wherein the fuel additive is selected to facilitate fueling a dross processing reaction.

[0088] Example 21 is the reconstituted metal recycling by-product of example(s) 17-20, wherein each of the pellets has an average diameter in the range of 5 mm to 50 mm.

[0089] Example 22 is the reconstituted metal recycling by-product of example(s) 17-21, wherein the dross further comprises salt.

[0090] Example 23 is a method for extracting salt from metal recycling by-products, the method including: charging a container with dross comprising aluminum oxide and salt; heating the dross to a temperature sufficiently high to vaporize the salt; maintaining the dross at the temperature to permit evaporation of the salt as a salt-laden vapor; directing the salt-laden vapor out of the container through a gas outlet; and obtaining the salt-laden vapor.

[0091] Example 24 is the method of example(s) 23, wherein obtaining the salt-containing vapor comprises condensing the salt-containing vapor into a solid or liquid salt.

[0092] Example 25 is the method of example(s) 23 or 24, wherein the salt comprises NaCl and the temperature is at or about 1450°C.

[0093] Example 26 is the method of example(s) 23-25, wherein the salt comprises KCl and the temperature is at or about 1416°C.

[0094] Example 27 is the method of example(s) 23-26, wherein the dross comprises a compound selected from the group consisting of nitrides, carbides, sulfides, and phosphides, and maintaining the dross at the temperature further comprises maintaining the dross at the temperature in an oxidizing environment.

[0095] Example 28 is the method of example(s) 23-27, wherein the dross comprises residual carbon, and heating the dross to the temperature comprises oxidizing the residual carbon.

[0096] Example 29 is the method of example(s) 23-28, wherein the dross comprises residual metallic aluminum, and heating the dross to the temperature comprises oxidizing the residual metallic aluminum.

[0097] Example 30 is the method of example(s) 23-29, wherein maintaining the dross at the temperature includes maintaining the dross at the temperature until at least 95% of the salt has evaporated.

[0098] Example 31 is the method of any one of examples 23-30, including removing treated dross from the vessel, wherein the vessel contains residual heat after removing the treated dross; and filling the vessel with additional dross and processing the additional dross, wherein processing the additional dross includes using the residual heat of the vessel.

[0099] Example 32 is the method of example(s) 23-31, wherein maintaining the dross at the temperature to allow evaporation of the salt further includes detecting a concentration of the salt-containing vapor exiting the gas outlet and determining to stop maintaining the dross at the temperature based on the detected concentration of the salt-containing vapor.

[0100] Example 33 is the method of example (s) 32, wherein detecting the concentration of the salt-containing vapor includes detecting an opacity of the salt-containing vapor present at the gas outlet.

[0101] Example 34 is a system for extracting salt from metal recycling by-products, the system including a vessel for receiving dross comprising aluminum oxide and salt; a heat source coupled to the vessel for heating the dross to a temperature high enough to vaporize the salt as a salt-laden vapor; a gas outlet coupled to the vessel for conveying gas and salt-laden vapor from the vessel; and a salt collector coupled to the gas outlet for collecting and condensing the salt-laden vapor.

[0102] Example 35 is the system of example or examples 34, wherein the salt comprises NaCl and the heat source is adapted to heat the dross to a temperature of about 1450° C. or greater.

[0103] Example 36 is the system of example(s) 34 or 35, wherein the salt includes KCl and the heat source is adapted to heat the dross to a temperature of about 1416° C. or greater. In some cases, the salt includes both KCl and NaCl.

[0104] Example 37 is the system of examples 34-36, wherein the vessel includes an oxygen inlet for establishing an oxidizing environment, and the dross includes a compound selected from the group consisting of nitrides, carbides, sulfides, and phosphides.

[0105] Example 38 is the system of examples 34-37, wherein the vessel includes an oxygen inlet for establishing an oxidizing environment, the dross includes residual carbon, and the oxidizing environment is suitable for oxidizing the residual carbon to facilitate heating the dross to the temperature.

[0106] Example 39 is the system of examples 34-38, wherein the vessel includes an oxygen inlet for establishing an oxidizing environment, the dross includes residual metallic aluminum, and the oxidizing environment is suitable for oxidizing the residual metallic aluminum to facilitate heating the dross to the temperature.

[0107] Example 40 is the system of any one of examples 33-39, further comprising a sensor for detecting a concentration of salt-containing vapor exiting the gas outlet.

[0108] Example 41 is the system of example (s) 40, wherein the sensor includes an optical sensor for detecting opacity of the salt-containing vapor exiting the gas outlet.

[0109] Example 42 is the system of example(s) 34-41, wherein the heat source comprises an oxy-fuel burner.

[0110] Example 43 is a method for treating a metal recycling by-product, comprising: filling a container with white dross containing aluminum oxide; introducing salt into the container; contacting the white dross with the salt at a first temperature to facilitate extraction of metal from the white dross and production of Glauber's salt; heating the Glauber's salt to a second temperature sufficiently high to evaporate the salt, the first temperature being lower than the second temperature; maintaining the Glauber's salt at the second temperature to permit evaporation of the salt as a salt-containing vapor, the evaporation of the salt from the Glauber's salt resulting in an inert oxide; draining the inert oxide; collecting the salt-containing vapor; condensing the salt-containing vapor into salt; and contacting the recycled salt with subsequent white dross to recycle the salt and produce subsequent Glauber's salt.

[0111] Example 44 is the method of example(s) 43, wherein contacting the white dross with the salt at the first temperature and heating the Glauber's salt to the second temperature occurs in the vessel.

[0112] Example 45 is the method of example (s) 44, wherein the vessel contains residual heat after discharging the inert oxide, and the subsequent producing of Glauber's salt includes using the residual heat of the vessel.

[0113] Example 46 is the method of example(s) 43-45, wherein the salt comprises NaCl and the second temperature is about 1450° C. or greater.

[0114] Example 47 is the method of example(s) 43-46, wherein the salt comprises KCl and the second temperature is about 1416° C. or greater.

[0115] Example 48 is the method of any one of examples 43-47, wherein the white dross comprises a compound selected from the group consisting of nitrides, carbides, sulfides, and phosphides, and maintaining the mirabilite at the second temperature further comprises maintaining the mirabilite at the second temperature in an oxidizing environment.

[0116] Example 49 is the method of any one of examples 43-48, wherein the Glauber's salt comprises residual metallic aluminum, and heating the Glauber's salt to the second temperature comprises oxidizing the residual metallic aluminum.

[0117] Example 50 is the method of example(s) 43-49, wherein maintaining the Glauber's salt at the second temperature comprises maintaining the Glauber's salt at the second temperature until at least 95% of the salt has evaporated.

[0118] Example 51 is the method of any one of examples 43 to 50, wherein maintaining the Glauber's salt at the second temperature to allow evaporation of the salt further includes detecting a concentration of the salt-containing vapor exiting the vessel and determining to stop maintaining the Glauber's salt at the second temperature based on the detected concentration of the salt-containing vapor.

[0119] Example 52 is the method of example(s) 51, wherein detecting the concentration of the saline vapor includes detecting an opacity of the saline vapor.

[0120] Example 53 is the method of example(s) 43-51, further comprising recycling at least a portion of the recycled salt for a use other than producing subsequent Glauber's salt.

[0121] Example 54 is the method of example(s) 53, wherein the use other than subsequent production of Glauber's salt comprises using the salt to facilitate melting of scrap metal. Some embodiments of the present disclosure are described in [Item 1] to [Item 22] below. [Item 1] dross, the dross comprising aluminum oxide; and 1. A reconstituted metal recycling by-product containing an additive selected to oxidize or decompose at a temperature of 800°C or less, the dross and the additive are agglomerated together into a pellet, the additive being disposed within the pellet such that one or more channels through the pellet are exposed upon oxidation of the additive; The reconstituted metal recycling by-product. [Item 2] 2. The reconstituted metal recycling by-product of claim 1, wherein the additive comprises post-consumer scrap or other industrially derived waste. [Item 3] 3. The reconstituted metal recycling by-product of claim 1 or 2, wherein the dross of the pellets comprises agglomerated dross particles each having an average diameter of 10 mm or less. [Item 4] 4. The reconstituted metal recycling by-product of any of items 1 to 3, further comprising a fuel additive, the fuel additive selected to facilitate fueling the dross processing reaction. [Item 5] 5. The reconstituted metal recycled by-product of any of items 1 to 4, wherein each of the pellets has an average diameter in the range of 5 mm to 50 mm. [Item 6] 6. The reconstituted metal recycling by-product of any of items 1 to 5, wherein the dross further comprises salt. [Item 7] providing dross pellets, each of the dross pellets comprising dross and an additive selected to oxidize or decompose at a channel exposure temperature of 800°C or less, the additive being disposed within the pellet and exposing channels of the pellet upon oxidation; heating the dross pellet to a temperature equal to or greater than the channel exposure temperature; oxidizing or decomposing the additive to expose the channels in each pellet, the channels in the pellet allowing gas to enter and pass through the pellet; maintaining the dross pellets at said temperature to heat treat the dross pellets; 2. A method for treating metal recycling by-products according to item 1, comprising: [Item 8] 8. The method according to claim 7, wherein the heat treatment comprises evaporating salt from the dross pellets. [Item 9] 9. The method of claim 7 or 8, wherein the additive comprises post-consumer scrap or other industrial waste. [Item 10] 10. The method of any of items 7 to 9, wherein the dross pellets further comprise a fuel additive selected to facilitate fueling to the heat treatment. [Item 11] 11. The method according to any one of items 7 to 10, wherein each of the dross pellets has an average diameter in the range of 5 mm to 50 mm. [Item 12] 12. The method according to any one of items 7 to 11, further comprising removing the treated dross pellets after heat treating the dross pellets, wherein the treated dross pellets have a carbon content of 1 wt% or less. [Item 13] Accepting dross pieces, Crushing the dross pieces into dross particles with a diameter of 10 mm or less; agglomerating the dross particles into pellets, the pellets comprising channels when heated to a temperature of 800°C or greater; 2. A method for pre-treating the reconstituted metal recycling by-product of item 1, comprising: [Item 14] 14. The method of claim 13, further comprising mixing the dross particles with an additive selected to oxidize or otherwise decompose at a temperature of 800°C or less, wherein the oxidation or decomposition of the additive promotes exposing the channels in the pellet. [Item 15] 15. The method of claim 14, wherein the additive comprises post-consumer scrap or other industrial waste. [Item 16] 16. The method of any of items 13 to 15, further comprising extracting metallic aluminum from the dross particles before agglomerating the dross particles. [Item 17] Item 17. The method of item 16, wherein extracting the metallic aluminum from the dross particles includes using an eddy current separator. [Item 18] 18. The method of any of items 13 to 17, further comprising screening the dross particles before agglomerating the dross particles, wherein screening comprises removing large dross particles. [Item 19] 20. The method of claim 18, wherein removing large dross particles comprises directing the large dross particles to further disintegrate. [Item 20] 20. The method of any of items 13 to 19, further comprising mixing the dross particles with a fuel additive, the fuel additive selected to promote fueling of the dross processing reaction. [Item 21] 21. The method according to any of items 13 to 20, wherein each of the pellets has an average diameter in the range of 5 mm to 50 mm. [Item 22] 22. The method of any of items 13 to 21, wherein the dross pieces comprise aluminum oxide and salt.

Claims

1. 1. A system for extracting salt from metal recycling by-products, comprising: a container for receiving the dross containing aluminum oxide and salt; a heat source coupled to the vessel for heating the dross to a temperature sufficiently high to vaporize the salt as a salt-containing vapor; a gas outlet coupled to the vessel for conveying gas and salt vapor from the vessel; and a salt collector coupled to the gas outlet for collecting and condensing the salt-containing vapor. The system.

2. 10. The system of claim 1, wherein the salt comprises NaCl and the heat source is adapted to heat the dross to a temperature of about 1450°C or greater.

3. 10. The system of claim 1, wherein the salt comprises KCl and the heat source is adapted to heat the dross to a temperature of about 1416°C or greater.

4. 10. The system of claim 1, wherein the vessel includes an oxygen inlet for establishing an oxidizing environment, and the dross includes compounds selected from the group consisting of nitrides, carbides, sulfides, and phosphides.

5. 2. The system of claim 1, wherein the vessel includes an oxygen inlet for establishing an oxidizing environment, the dross including residual carbon, and the oxidizing environment is suitable for oxidizing the residual carbon to facilitate heating the dross to the temperature.

6. 2. The system of claim 1, wherein the vessel includes an oxygen inlet for establishing an oxidizing environment, the dross including residual metallic aluminum, and the oxidizing environment is suitable for oxidizing the residual metallic aluminum to facilitate heating the dross to the temperature.

7. The system of claim 1 further comprising a sensor for detecting a concentration of salt-containing vapor exiting the gas outlet.

8. The system of claim 7 , wherein the sensor comprises an optical sensor for detecting the opacity of the salt-laden vapor exiting the gas outlet.

9. The system of claim 1 , wherein the heat source comprises an oxy-fuel burner.

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