WO2025207831A1 - Rotary kiln apparatus and methods of use - Google Patents

Abstract

Set forth herein are rotary kiln apparatus that are not lined with refractory materials and that are useful for battery recycling. Also set forth herein are processes for using these apparatus.

Description

ROTARY KILN APPARATUS AND METHODS OF USE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 63/572,166, filed March 29, 2024, the entire contents of which are herein incorporated by reference in their entirety for all purposes.

FIELD

[0002] The present disclosure concerns the recycling of batteries, battery components, devices that include batteries, and other related electronic devices and materials.

BACKGROUND OF THE INVENTION

[0003] Batteries, and in particular rechargeable batteries, are increasingly being used in transportation and electrical device applications. Lithium-ion batteries, for example, are a type of rechargeable batteries that is widely being adopted in a variety of automotive applications, from personal vehicles to autonomous fleets of robots, drones, and transportation devices.

[0004] The abundance of rechargeable batteries creates a waste problem once these batteries expend their useful lifetime. The production of batteries also creates battery scrap production waste. Recycling is one solution to this waste problem. However, recycling of batteries involves a variety of challenges.

[0005] One challenge is making and using energy-efficient techniques and devices for extracting high value metals from battery scrap. Another challenge is providing processing conditions that break down battery scrap in a useful way. Another challenge is efficiently extracting lithium, nickel, manganese, cobalt, copper, aluminum, graphite, and combinations thereof, in sufficient yields and purity for making new batteries. Yet another challenge still is recycling battery materials and scrap in an economically viable manner.

[0006] What is needed are processes, methods, and apparatus for recycling batteries continuously and in an energy-efficient manner. Set forth herein are solutions to the aforementioned challenge as well as others in the relevant field to which the instant disclosure pertains.

SUMMARY OF THE INVENTION

[0007] In one embodiment, set forth herein is a rotary kiln that includes an inlet airlock; an outlet airlock; and a heater configured to indirectly heat the rotary kiln. The rotary kiln, in certain embodiments, is not lined with a refractory material. In certain embodiments, the inlet airlock is configured to accept batteries, black mass, and/or battery scrap and the outlet airlock is configured to discharge the product of calcining the batteries, black mass, and/or battery scrap. This product is referred to in some embodiments as calcined metal concentrate.

[0008] In a second embodiment, set forth herein is a rotary kiln that includes an inlet solid airlock; an outlet solid airlock; and a heater configured to indirectly heat the rotary kiln, in which the rotary kiln is not lined with a refractory material.

[0009] In a third embodiment, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; calcining the battery scrap in the rotary kiln; wherein the atmosphere in the rotary kiln is a reducing atmosphere; and continuously outputting calcined metal concentrate out of the rotary kiln.

[0010] In a fourth embodiment, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; heating the battery scrap in a reducing atmosphere in the rotary kiln until a steadystate reaction is achieved; reducing heating, stopping heating, or both; and continuously outputting calcined metal concentrate out of the rotary kiln.

[0011] In a fifth embodiment, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; maintaining the temperature in the rotary kiln at 200 °C to 800 °C using at least one steady -state reaction and no external heating; wherein the atmosphere in the rotarykiln is a reducing atmosphere; and continuously outputting calcined metal concentrate out of the rotary kiln.

[0012] In a sixth embodiment, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; maintaining in the rotary kiln a set-point temperature using a feedback loop by modulating one or more members selected from (a) through (1):

(a) heat applied to the rotary kiln;

(b) temperature inside the rotary kiln;

(c) O2 concentration in the rotary kiln or outlet;

(d) N2 concentration in the rotary kiln or outlet;

(e) rotary kiln rotation rate;

(f) bed height in the rotary kiln;

(g) residence time in the rotary kiln;

(h) rotary kiln input rate (i.e. , feed rate);

(i) feed type based on contained energy;

(j) feed type based on form factor;

(k) rotary kiln output rate; or

(l) a combination of (a), (b), (c), (d), (e), (f), (g), (h), (i), (j), or (k); and continuously outputting calcined metal concentrate out of the rotary kiln.

BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 shows an embodiment of a system and process for conveying battery scrap through a recycling apparatus disclosed here.

[0014] FIG. 2 shows an embodiment of a rotary kiln set forth herein.

DETAILED DESCRIPTION OF THE INVENTION

DEFINITIONS

[0015] As used herein, the phrase “active material powder,” refers to fractions from shredded or comminuted electrochemical cells. The active material powder may include a powder comprising electrode materials including electrode active materials, polymeric binder, and aluminum, nickel, and copper current collector material. The chemical composition of active material powder depends upon the chemistry of the scrap electrochemical cells input. Active material powder may include nickel and nickel compounds, copper and copper compounds, graphite, lithium metal and lithium compounds, polymers, binders, oxides thereof, as well as combinations thereof. Active material powder includes the powdered form of cathode active material (CAM). Active material powder includes powdered “cathode material,” which is the positive electrode component of a battery and includes cathode active materials, binders, organic solvents, lithium salts, and lithium-ion conducting materials, as well as combinations thereof. Cathode materials may include, but are not limited to, lithium iron phosphate active materials (e.g, LFP), lithium manganese iron phosphate active materials (e.g, LFMP), nickel manganese cobalt oxide active materials (e.g, NMC622, NMC811), manganese oxides, nickel oxides, cobalt oxides, and combinations thereof. Active material powders includes a cathode material that further includes various amounts of lithium.

[0016] As used herein, the phrase “black mass,” refers to fractions from shredded or comminuted electrochemical cells. The black mass may include a powder comprising electrode materials including electrode active materials, polymeric binder, and aluminum, nickel, and copper current collector material. The chemical composition of black mass depends upon the chemistry of the scrap electrochemical cells input. Black mass may include nickel and nickel compounds, copper and copper compounds, graphite, lithium metal and lithium compounds, polymers, binders, oxides thereof, and the calcined metal components thereof, as well as combinations thereof.

[0017] As used herein, the phrase “anode material,” refers to the negative electrode component of a battery and includes anode active materials, graphite, silicon, lithium, and combinations thereof. Anode material may also include current collector material, such as copper, aluminum, and nickel.

[0018] As used herein, the phrase “atmosphere in the rotary kiln is reducing” refers to the condition inside the rotary kiln that has less oxygen than in the atmosphere on planet Earth. A reducing atmosphere may also include hydrocarbons produced from battery reactions (e.g., decomposition, calcination, evaporation), N2, H2, CO2, Ar, or a combination thereof. A reducing atmosphere may include hydrocarbons evaporated or released from a battery or a device housing a battery. A reducing atmosphere has less than 10% by volume oxygen, and typically less than 4% by volume oxygen with the remainder being hydrocarbons. In some embodiments, N2, H2, CO2, Ar, or a combination thereof, may also be present in the rotary kiln in addition to hydrocarbons. In certain embodiments, the reducing atmosphere is useful for causing lithium to precipitate, or be extracted as, as lithium hydroxide (LiOH) in the calcined metal concentrate instead as lithium carbonate (I^CCh). In certain embodiments, the calcined metal concentrate comprises LiOH. In certain embodiments, the calcined metal concentrate comprises more LiOH than Li2COs. In certain embodiments, the reducing atmosphere is useful for reducing the oxidation of aluminum in the rotary kiln. In certain embodiments, the reducing atmosphere is useful for reducing the oxidation of carbon in the rotary kiln. In certain embodiments, the reducing atmosphere is useful for reducing the oxidation of graphite in the rotary kiln.

[0019] As used herein, the phrase “coupled, directly or indirectly,” refers to the manner in which two pieces of equipment in a process line are connected. A feeder that places material directly from the feeder onto a conveyor belt is coupled directly to the conveyor belt. There is no other equipment, in this particular example, between the feeder and the conveyor belt, and over which material is moved during processing. As such, the feeder and conveyor belt, in this example, are coupled directly. A conveyor belt that moves material into a shredder, and in which the shredder’s outfeed chute deposits material onto a second conveyor belt that moves material to an impact mill, is coupled indirectly with the second conveyor belt. In this second example, there is other equipment between the conveyor belt and the second conveyor belt, and over which material is moved during processing. Therefore, the conveyor belt and the second conveyor belt are coupled indirectly.

[0020] As used herein, the phrase “battery scrap,” refers to used batteries, such as but not limited to lithium-ion batteries, devices that include used batteries, as well as the components of used batteries. Battery scrap also includes battery production scrap, which is scrap material used to make a battery but before a battery is actually made. For example, waste material produced during the making of a battery would be a type of battery production scrap. A used battery includes, but is not limited to, a battery that has been charged, discharged, or both, at least once. A used battery includes, but is not limited to, a battery that has been sold. Inert battery scrap includes battery scrap that cannot be charged or has been discharged, for example by calcining the battery scrap at about 300 °C or higher. Live battery scrap includes batteries that could still be charged or that still carry a charge. Live battery scrap necessarily includes both a cathode and an anode configured together as a battery. Inert battery scrap may include a cathode and an anode or may just include cathode active materials optionally with the current collector.

[0021] As used herein, “live battery scrap,” includes batteries that are charged or that could be charged without further assembly of the battery. Live battery scrap can be transformed into inert battery scrap by calcining the live battery scrap.

[0022] As used herein, the phrase “lithium-ion battery scrap,” refers to battery scrap as defined above that is, or originates, from a lithium ion battery. Lithium-ion battery scrap includes, but is not limited to, cathode active materials, anode active materials, current collector materials, and other battery parts and components, such as but not limited to electrolytes.

[0023] As used herein, “calcining” or “calcination” refers to the process by which material is heated to a high temperature, e.g., a temperature over 80 °C, in order to decompose the material and removing volatile materials. Herein, calcining typically occurs under reducing conditions such that oxidation reactions are limited. By limiting oxidation reactions, improved rotary kiln temperature control is achieved.

[0024] As used herein, the phrase “continuously inputting” refers to a process in which material enters a rotary kiln while the rotary kiln is operating and while the rotary kiln has material inside the rotary kiln, and/or has material exiting the rotary kiln while the rotary kiln is operating and while the rotary kiln has material inside the rotary kiln. Herein continuously conveying refers to a process in which material is being conveyed in a manner that does not stop while other process apparatus are operating, such as, but not limited to, the rotary kiln, an impact mill, and size reduction devices. For example, if a rotary kiln is calcining battery scrap while more battery scrap is entering or exiting the rotary kiln, then the battery scrap is being continuously conveyed into the rotary kiln. For example, if an impact mill is milling calcined metal concentrate while more calcined metal concentrate is entering or exiting the impact mill, then the calcined metal concentrate is being continuously conveyed into, or out of, the impact mill.

[0025] As used herein, the phrase “continuously outputting” refers to a process in which material exits a rotary kiln while the rotary kiln is operating and while the rotary kiln has material inside, and/or in which material enters the rotary kiln while operating and while the rotary kiln has material inside.

[0026] As used herein, “downstream,” refers to process and apparatus components that are positioned after another part, in which “after” is relative to the direction of travel of materials in a process line during a recycling process.

[0027] As used herein, “upstream,” refers to process and apparatus components that are positioned before another part, in which “before” is relative to the direction of travel of materials in a process line during a recycling process.

[0028] As used herein, the phrase “heater configured to indirectly heat,” refers to a device for heating that is not providing heat inside the rotary kiln. For example, some rotary kilns include internal heaters or devices for introducing a flame or fire inside the rotary kiln. These are examples of direct heating. Contrary to direct heating, indirect heating includes, for example and without limitation, electrical heaters that are positioned on the outside of the rotary kiln. When activated, these external electrical heaters indirectly heat the rotary kiln from the outside. Another form of indirect heat is the heat released by exothermic reactions that occur inside the rotary kiln when the materials in the rotary kiln react, for example and without limitation, oxidative reactions, e.g, combustion, and/or in steady-state reactions.

[0029] As used herein, the phrase “no external heating” refers to the condition in which no external heating, including no indirect electrical heating, is applied to the rotary kiln.

[0030] As used herein, the phrase “refractory,” refers to the property of a non-metallic material to be resistant to heat and chemical degradation. Refractory materials also tend to maintain strength and rigidity at elevated temperatures. Certain ceramics are considered refractory materials but metals are not considered refractory materials. For example, certain ceramics may be heated to high temperatures in air without undergoing any chemical or physical changes. Metals, by contrast, tend to melt if not also oxidize when heated to high temperatures in air. Metals conduct heat well whereas ceramics tend not to conduct heat well. Because of their resistance to heat, refractory materials are often used in certain kilns, furnaces, reactors, and vessels that transport molten metal. [0031] As used herein, a “rotary kiln” refers to a kiln that rotates. A rotary kiln is configured to raise the temperature of materials inside the kiln that are moved continuously into and out of the rotary kiln while the rotary kiln is rotating. A rotary kiln rotates along its longitudinal axis. As material moves from the inlet to the outlet, the material is heated and mixed while being moved.

[0032] As used herein, a “solid airlock” refers to a device for sealing a rotary kiln and also for introducing or removing material from the rotary kiln. A solid airlock has space to accommodate material that is being moved into or out of the rotary kiln, while preventing or reducing air flow into the kiln. In certain embodiments, the rotary kiln operates under a mild vacuum. A solid airlock also has a device for sealing the rotary kiln from more material entering or exiting the rotary kiln as well as for sealing gases inside the rotary kiln.

[0033] As used herein, “size reduction processes,” refers to processes that cause the size of a material to be reduced. Shredders, milling devices, impact mills, gnnders, disassemblers, and similar devices are useful for downsizing a material or, equivalently, reducing the particle size of the material.

[0034] As used herein, the phrase “steady-state reaction,” refers to a reaction, or set of reactions, in which all state variables are constant in spite of ongoing processes that strive to change them. For example, in a rotary kiln, material exits while other material enters. Despite this change in material in and out, the temperature in the kiln remains constant due to the reactions occurring inside the rotary kiln. In some examples, external energy may be applied to activate a steady-state condition, and then the heat may be removed or reduced as the steady -state is achieved and maintained. In a steady state reaction, the rate of product formation and reactant consumption are approximately equal. In certain embodiments, minimal to no heat (e.g., external, indirect heat) is required when the rotary kiln is operating at a steady - state. In some embodiments, the heaters are turned off if too much heat is building up in the rotary kiln or if the rotary kiln exceeds a certain set-point temperature. In some other embodiments, dunng a steady-state process, some nitrogen may be introduced into the rotary kiln to cool the system if too much heat is building up in the rotary kiln or if the rotary kiln exceeds a certain set-point temperature. [0035] As used herein, “temperature sensors are located in the rotary kiln and spaced apart to determine temperature variations as a function of kiln length,” refers to a configuration of temperature sensors that are placed along the length of the kiln. The sensors are placed at particular locations such that a measurement from all or a collection of sensors indicates the temperature of the kiln as a function of the length along which the temperature sensors are placed.

[0036] As used herein, the phrase “not cooled actively,” refers to a process step in which a material cools on its own by either radiating heat or conducting heat with a substrate on which the material is disposed. A material is not cooled actively when external devices, such as an air conditioner, or blower, are not used to cool the temperature of the material.

[0037] As used herein, the phrase “magnetic separation device,” refers to a device capable of separating magnetic from nonmagnetic material. For example, a table that has a magnet on or in it will attract milled iron in a collection of milled iron, milled aluminum, and milled copper. Of these three metals, only iron might be magnetic; aluminum and copper are not magnetic. In a processing line, a collection of materials may include different types of metals. A magnet separation device would be used to separate or isolate the magnetic components from the non-magnetic components. As the processing line progresses, iron would accumulate on the magnet of the magnetic separation device and nonmagnetic material would continue to move past the magnetic separation device. Commercially available magnetic separation devices include, but are not limited to, a magnetic drum separator, a vibratory feed magnetic plate separator, a magnetic plate separator (i.e., in a transition chute), and a cross-belt magnetic separator.

[0038] As used herein, the phrase “separated aluminum,” refers to aluminum that has a higher purity of aluminum than in the battery scrap from which it was recycled and processed.

[0039] As used herein, the phrase “intact aluminum,” refers to solid aluminum that is mechanically isolatable from other materials in which the intact aluminum is mixed. Intact aluminum is also aluminum that is not melted aluminum. [0040] As used herein, the phrase “separated copper,” refers to copper that has a higher purity of copper than in the battery scrap from which it was recycled and processed.

ROTARY KILNS

[0041] In some embodiments, set forth herein is a rotary kiln that includes an inlet solid airlock; an outlet solid airlock; and a heater configured to indirectly heat the rotary kiln; and wherein the rotary kiln is not lined with a refractory material. In certain embodiments, the rotary kiln is lined with a metal or an alloy of a metal.

[0042] In some other embodiments, set forth herein is a rotary kiln that includes an inlet airlock; an outlet airlock; and a heater configured to indirectly heat the rotary kiln; and wherein the rotary kiln is not lined with a refractory material. In certain embodiments, the inlet airlock is configured to accept batteries, black mass, and/or battery scrap and the outlet airlock is configured to discharge the product of calcining the batteries, black mass, and/or battery scrap. In certain embodiments, the inlet airlock is configured to accept live batteries, and the outlet airlock is configured to discharge inert battery material. This product is referred to in some embodiments as calcined metal concentrate. Calcined metal concentrate may include active material powder, ferrous fractions, non-ferrous fractions, e.g., copper flake and aluminum flake. In certain embodiments, the calcined metal concentrate comprises LiOH. In certain embodiments, the calcined metal concentrate comprises more LiOH than Li2COs. In certain embodiments, the rotary kiln is lined with a metal or an alloy of a metal.

[0043] In some embodiments, the internal volume of the rotary' kiln is about 60 m³.

[0044] In some embodiments, the internal volume of the rotary' kiln is greater than, or equal to 60 m³, but less than, or equal to, 100 m³.

[0045] In some embodiments, the internal volume of the rotary' kiln is greater than, or equal to 20 m³, but less than, or equal to, 100 m³.

[0046] In some embodiments, the internal volume of the rotary' kiln is greater than, or equal to 10 m³, but less than, or equal to, 100 m³.

[0047] In some embodiments, including any of the foregoing, the rotary kiln is made of a metal or an alloy thereof. [0048] In some embodiments, including any of the foregoing, the rotary kiln is made of stainless steel, carbon steel, or a combination thereof.

[0049] In some embodiments, including any of the foregoing, the rotary kiln is coupled upstream to a feed conveyor and chute.

[0050] In some embodiments, including any of the foregoing, the inlet solid airlock or outlet solid airlock, or both, is a knife-gate air lock; or a rotary airlock.

[0051] In some embodiments, including any of the foregoing, the rotary kiln is coupled downstream to a discharge chute and conveyor.

[0052] In some embodiments, including any of the foregoing, the rotary kiln is coupled to a source of nitrogen (e.g., liquid nitrogen tank), vaporizer, or a combination thereof.

[0053] In some embodiments, including any of the foregoing, the rotary kiln is coupled to a variety of gas sources (e.g. , air, argon, a liquid nitrogen tank, etc.. . ). In certain embodiments, including any of the foregoing, the rotary kiln is coupled to an inert gas source selected from the group consisting of N2, H2, CO2, Ar, or a combination thereof. In certain embodiments, including any of the foregoing, the rotary kiln is coupled to aN2 gas source. In certain embodiments, including any of the foregoing, the rotary kiln is coupled to an H2 gas source. In certain embodiments, including any of the foregoing, the rotary kiln is coupled to a CO2 gas source. In certain embodiments, including any of the foregoing, the rotary kiln is coupled to an Ar gas source. In certain embodiments, including any of the foregoing, the rotary kiln is coupled to a combination of gas sources that include N2, H2, CO2, and Ar. In certain embodiments, including any of the foregoing, the rotary kiln is coupled to a combination of gas sources that include N2 and H2. In certain embodiments, including any of the foregoing, the rotary kiln is coupled to a combination of gas sources that include Ar and H2. In certain embodiments, H2 gas is used to cause lithium to precipitate as lithium hydroxide (LiOH) in the calcined metal concentrate instead of as lithium carbonate (I^CCh).

[0054] In some embodiments, including any of the foregoing, the heater is an electrical heater. In some of these embodiments, the heater is a 1.5 megawatt (MW) heater. In some of these embodiments, the heater is a 2 megawatt (MW) heater. In some of these embodiments, the heater is a 3 megawatt (MW) heater. In some of these embodiments, the heater is a 4 megawatt (MW) heater. In some of these embodiments, the heater is a 5 megawatt (MW) heater. In some of these embodiments, the heater is a 6 megawatt (MW) heater. In some of these embodiments, the heater is a 7 megawatt (MW) heater. In some of these embodiments, the heater is an 8 megawatt (MW) heater. In some of these embodiments, the heater is a 9 megawatt (MW) heater. In some of these embodiments, the heater is a 10 megawatt (MW) heater.

[0055] In some embodiments, including any of the foregoing, the rotary kiln further includes a means for detecting blockages. In some embodiments, including any of the foregoing, the means for detecting blockages are selected from cameras, electromagnetic sensors, and combinations thereof. In some embodiments, including any of the foregoing, the means for detecting blockages are cameras. In some embodiments, including any of the foregoing, the means for detecting blockages are electromagnetic sensors.

[0056] In some embodiments, including any of the foregoing, the rotary kiln further includes means for removing blockages. In some embodiments, including any of the foregoing, the means for removing blockages are at least one actuated pusher plate.

[0057] In some embodiments, including any of the foregoing, the rotary kiln is coupled, directly or indirectly, to at least one mechanical separator. In certain embodiments, the mechanical separator includes multiple devices for size reduction processes. In some other embodiments, the mechanical separator includes at least one vibratory screener, magnetic separator, size reducer, or a combination thereof.

[0058] In some embodiments, including any of the foregoing, the apparatus further includes oxygen sensors, temperature sensors, and pressure sensors, or a combination thereof.

[0059] In some embodiments, including any of the foregoing, the apparatus further includes oxygen sensors. In some embodiments, the oxygen sensors are disposed at the outlet of the kiln. [0060] In some embodiments, including any of the foregoing, the apparatus further includes temperature sensors. In some of these embodiments, the temperature sensors are located in the rotary kiln.

[0061] In some embodiments, including any of the foregoing, the temperature sensors are located in the rotary kiln and are spaced apart.

[0062] In some embodiments, including any of the foregoing, the temperature sensors are located in the rotary kiln and spaced apart to determining temperature variations as a function of kiln length. The temperature sensors may also be configured as part of a feedback control system for maintaining a set-point temperature in the rotary kiln. In some embodiments, the indirect heating includes multiple heating components that are each independently controlled. In some embodiments, one heating component may be off while another heating component is on. In some embodiments, temperature sensors are matched to the position of each heating component. This allows for precise control of the heating components.

PROCESSES FOR USING ROTARY KILNS

[0063] FIG. 1 shows one embodiment of a process flow diagram useful for implementing a process or apparatus herein. FIG. 1 shows a rotary kiln that is coupled to a source of gas. In some embodiments, the source of gas is a source of N2 or another inert gas. In some embodiments, the source of gas is a liquid nitrogen tank and a vaporizer. The rotary kiln is labeled as a rotary calciner in FIG. 1. The rotary calciner has a feed conveyor and airlock chute coupled upstream thereof. The rotary calciner has a discharge airlock chute and conveyor coupled downstream thereof. Battery feed is input into the feed conveyor and airlock chute. This battery feed may be battery scrap. Hot metal concentrate is output from the rotary calciner into the discharge airlock chute and conveyor. The hot metal concentrate is then conveyed further downstream to three size reduction devices and a vibratory screen. As the hot metal concentrate moves through the process line, the hot metal concentrate cools. In some embodiments, the apparatus over and on which the hot metal concentrate is conveyed is configured to control the cooling of the hot metal concentrate. Material conveyed to the vibratory screener is separated based on size and then separated with a magnetic separator. After the magnetic separator, ferrous midsize material, nonferrous midsize material, nonferrous oversize material, and ferrous oversize material. are individually separated. Also shown in FIG. 1 are various ventilation and dust collection devices.

[0064] In some embodiments, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; calcining in the rotary kiln the battery scrap; wherein the atmosphere in the rotary kiln is reducing; and continuously outputting calcined metal concentrate out of the rotary kiln.

[0065] In some embodiments, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting black mass into a rotary' kiln; calcining in the rotary kiln the black mass; wherein the atmosphere in the rotary kiln is reducing; and continuously outputting calcined metal concentrate out of the rotary kiln.

[0066] In certain embodiments, battery scrap includes at least one battery, battery module, battery pack, device that includes a battery , component thereof, or combinations thereof.

[0067] In some embodiments, including any of the foregoing, the outputting calcined metal concentrate includes conveying calcined metal concentrate out of the rotary kiln. The calcined metal concentrate may be hot and have a temperature greater than room temperature. The calcined metal concentrate, in some embodiments, may be conveyed into a shredder, milling device, or combination thereof, while the calcined metal concentrate is above room temperature.

[0068] In some embodiments, including any of the foregoing, the calcining occurs at 20 °C to 800 °C.

[0069] In some embodiments, including any of the foregoing, the calcining occurs at 20 °C to 900 °C.

[0070] In some embodiments, including any of the foregoing, the calcining occurs at 300 °C to 800 °C.

[0071] In some embodiments, including any of the foregoing, the calcining occurs at 300 °C to 900 °C. [0072] In some embodiments, including any of the foregoing, the calcining occurs at less than 660 °C to prevent aluminum from melting.

[0073] In some embodiments, including any of the foregoing, the calcining occurs at 200 °C to 800 °C.

[0074] In some embodiments, including any of the foregoing, the calcining occurs without external heating.

[0075] In some embodiments, including any of the foregoing, the calcining proceeds as at least one steady-state reaction.

[0076] In some embodiments, including any of the foregoing, the process also includes adjusting a rate of continuously inputting, continuously outputting, or both, to achieve steady-state conditions.

[0077] In some embodiments, including any of the foregoing, the process also includes reducing or eliminating indirect heating when the process is at steady-state conditions. In certain embodiments, the process includes reducing or eliminating indirect hearing, from an external heater positioned outside of the rotary kiln, when the process is at steady -state conditions. In some embodiments, external, indirect heat is applied to the rotary kiln in order to activate the steady-state reaction. Once the steady -state is achieved, the external, indirect heat is either no longer applied to the rotary kiln; or the external, indirect heat is reduced and then no longer applied to the rotary kiln. In some embodiments, if the steady-state was achieved but then stops for some reason, the indirect heating may be applied to restart the steady state reaction.

[0078] In some embodiments, including any of the foregoing, the process also includes introducing nitrogen when the process is at steady-state conditions. In certain embodiments, nitrogen is added to the rotary kiln during a steady-state condition but so as to lower the temperature in the rotary kiln.

[0079] In some embodiments, including any of the foregoing, the process include turning off heaters after a steady -state condition but when the temperature in the rotary kiln is above a certain temperature (e.g, 660 °C, which is the melting point of aluminum). [0080] In some embodiments, including any of the foregoing, the calcined metal concentrate is not cooled actively. Not cooled actively includes, in some examples, allowing the calcined metal concentrate to cool without blowing air on the calcined metal concentrate. Not cooled actively includes, in some examples, allowing the calcined metal concentrate to cool without dowsing the calcined metal concentrate with water.

[0081] In some embodiments, including any of the foregoing, the calcined metal concentrate is at 50 °C or greater. In certain of these embodiments, the calcined metal concentrate is conveyed while the material is at 50 °C or greater.

[0082] In some embodiments, including any of the foregoing, the calcined metal concentrate is at 50 °C to 800 °C. In certain of these embodiments, the calcined metal concentrate is conveyed while the material is at 50 °C to 800 °C.

[0083] In some embodiments, including any of the foregoing, the process also includes continuously conveying calcined metal concentrate into a shredder, a mechanical separator, or a combination thereof.

[0084] In some embodiments, including any of the foregoing, the process also includes shredding the calcined metal concentrate at a temperature above room temperature.

[0085] In some embodiments, including any of the foregoing, the oxygen concentration in the rotary kiln is 0 % to 10 % by volume.

[0086] In certain embodiments, the oxygen concentration in the rotary kiln is 0 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 1 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 2 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 3 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 4 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 5 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 6 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 7 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 8 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 9 % by volume. In certain embodiments, the oxygen concentration in the rotary kiln is 10 % by volume.

[0087] In some embodiments, including any of the foregoing, the oxygen concentration in the rotary kiln is less than 4 % by volume.

[0088] In some embodiments, including any of the foregoing, the oxygen concentration in the rotary kiln is less than 4 % by volume but greater than 0 % by volume.

[0089] In some embodiments, including any of the foregoing, the calcined metal concentrate includes aluminum metal, graphite, or both.

[0090] In some other embodiments, including any of the foregoing, the calcined metal concentrate does not include aluminum metal, graphite, or both.

[0091] In some embodiments, including any of the foregoing, the calcined metal concentrate includes aluminum metal.

[0092] In some embodiments, including any of the foregoing, the calcined metal concentrate includes intact aluminum metal.

[0093] In some embodiments, including any of the foregoing, the calcined metal concentrate includes calcined batteries that include more than 50% by mass of the graphite in the original amount of the at least one battery, battery module, battery pack, device that includes a battery, component thereof, or combinations thereof. In certain embodiments, this calcined metal concentrate has this composition as it exits the rotary kiln and before going to a shredding process. In certain embodiments, the calcined metal concentrate is screened out into the active material fraction and powder fraction.

[0094] In some embodiments, including any of the foregoing, the calcined metal concentrate includes nickel (Ni), cobalt (Co), copper (Cu), lithium (Li), and combinations thereof.

[0095] In some embodiments, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; heating, in a reducing atmosphere, the battery scrap until a steady-state reaction is achieved; reducing heating, stopping heating, or a combination thereof; and continuously outputting calcined metal concentrate, out of the rotary kiln.

[0096] In some embodiments, including any of the foregoing, the battery scrap includes at least one battery, battery module, battery pack, device that includes a battery, component thereof, or combinations thereof.

[0097] In some embodiments, including any of the foregoing, the heating is indirect electrical heating.

[0098] In some embodiments, including any of the foregoing, the outputting calcined metal concentrate includes conveying calcined metal concentrate out of the rotary kiln.

[0099] In some embodiments, including any of the foregoing, the steady-state reaction occurs at 200 °C to 800 °C.

[0100] In some embodiments, including any of the foregoing, the steady-state reaction occurs without external heating.

[0101] In some embodiments, including any of the foregoing, the calcined metal concentrate is not cooled.

[0102] In some embodiments, including any of the foregoing, the calcined metal concentrate is at 50 °C or greater.

[0103] In some embodiments, including any of the foregoing, the calcined metal concentrate is at 50 °C or greater, but less than or equal to 900 °C.

[0104] In some embodiments, including any of the foregoing, the process also includes continuously conveying calcined metal concentrate into sized reduction equipment, size separation equipment, or equipment for conveying material between other equipment.

[0105] In some embodiments, including any of the foregoing, the process also includes continuously conveying calcined metal concentrate into a shredder, a mechanical separator, or a combination thereof. [0106] In some embodiments, including any of the foregoing, the process also includes shredding the calcined metal concentrate at a temperature above room temperature.

[0107] In some embodiments, including any of the foregoing, the oxygen concentration in the rotary kiln is 0% to 10% by volume.

[0108] In some embodiments, including any of the foregoing, the oxygen concentration in the rotary kiln is less than 4% by volume.

[0109] In some embodiments, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting at least one battery, battery module, battery pack, device that includes a battery , component thereof, or combinations thereof, into a rotary kiln; maintaining in the rotary kiln a temperature of 200 °C to 800 °C, in a reducing atmosphere, using at least one steady-state reaction and no external heating; continuously outputting calcined metal concentrate, out of the rotary kiln.

[0110] In some embodiments, including any of the foregoing, the process also includes maintaining in the rotary kiln a temperature less than 660 °C.

[0111] In some embodiments, including any of the foregoing, the process also includes maintaining in the rotary kiln a temperature less than 400 °C.

[0112] In some embodiments, including any of the foregoing, the outputting calcined metal concentrate includes conveying calcined metal concentrate out of the rotary kiln.

[0113] In some embodiments, including any of the foregoing, the steady-state reaction occurs at 200 °C to 800 °C; 300 °C to 700 °C; 350 °C to 600 °C; 350 °C to 500 °C; or 530 °C to 500 °C.

[0114] In some embodiments, including any of the foregoing, the calcined metal concentrate is not cooled.

[0115] In some embodiments, including any of the foregoing, the calcined metal concentrate is at 50 °C or greater. [0116] In some embodiments, including any of the foregoing, the process also includes continuously conveying calcined metal concentrate into a shredder, a mechanical separator, or a combination thereof

[0117] In some embodiments, including any of the foregoing, the process also includes shredding the calcined metal concentrate at a temperature above room temperature.

[0118] In some embodiments, including any of the foregoing, the oxygen concentration in the rotary kiln is 0% to 10% by volume.

[0119] In some embodiments, including any of the foregoing, the oxygen concentration in the rotary kiln is less than 4% by volume.

[0120] In some embodiments, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; maintaining in the rotary kiln a set-point temperature using a feedback loop by modulating one or more members selected from (a) through (1):

(a) heat applied to the rotary kiln;

(b) temperature inside the rotary kiln;

(c) O2 concentration in the rotary kiln or outlet;

(d) N2 concentration in the rotary kiln or outlet;

(e) rotary kiln rotation rate;

(f) bed height in the rotary kiln;

(g) residence time in the rotary kiln;

(h) rate of material input (feed rate) into the rotary kiln;

(i) feed type based on contained energy;

(j) feed type based on form factor;

(k) rate of material output out of the rotary kiln; or

(l) a combination of (a), (b), (c), (d), (e), (f), (g), (h), (i), (j), or (k); and continuously outputting calcined metal concentrate out of the rotary kiln. [0121] Herein, the feed type based on contained energy refers to various feed types that, when calcined in a rotary kiln described herein, release certain amounts of energy. In the smelting industry, contained energy is often described as high energy feeds and low energy feeds. For example, devices with plastic casings have more contained energy than devices without plastic casings. This is because the plastic casings will release energy when calcined in the rotary kiln. In general, a feed with a low amount of plastic has a lower contained energy than a feed with a higher amount of plastic. A battery with a higher state-of-charge has a higher contained energy than a battery with a lower state-of-charge. A battery without an electrolyte has a lower contained energy than a live battery, or a battery with electrolyte that may also be charged but is at least capable of being charged.

[0122] Manufacturing scrap has a lower contained energy than a live battery at least because the live battery includes electrolytes (e.g, organic solvent electrolytes).

[0123] In some embodiments, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; maintaining in the rotary kiln a set-point temperature using a feedback loop by modulating the feed type based on contained energy. In some embodiments, when the rotary kiln is too hot, the feed ty pe may be switched to a feed type with a lower contained energy. In some embodiments, when the rotary kiln is not hot enough, the feed type may be switched to a feed type with a higher contained energy.

[0124] Herein, feed type based on form factor refers to various types of form factors that may be input into the rotary kiln. For example, modules are a different form factor than packs. Modules and packs are both different form factors from battery pouches and battery coin cells. Power tool battery packs are also a different form factor from a module, a pack, a pouch, or a coin cell. The instant disclosure contemplates running a continuous process in which the form factors conveyed into the rotary kiln may be changed depending on the temperature or other property in the rotary kiln. In some embodiments, set forth herein is a process for producing calcined metal concentrate that includes continuously inputting battery scrap into a rotary kiln; maintaining in the rotary kiln a set-point temperature using a feedback loop by modulating the feed ty pe based on form factor.

[0125] The instant disclosure contemplates the ability to achieve an energy balance in the rotary kiln by adjusting not just the total mass that moves into the rotary kiln but also the type of mass that is moving through the rotary kiln. The type of mass may change as a function of its form factor, its amount, or relative amount, of contained energy, or a combination thereof.

[0126] In some embodiments, including any of the foregoing, the process includes reducing heating if the temperature in the rotary kiln exceeds the set-point temperature.

[0127] In some embodiments, including any of the foregoing, the set-point temperature is at least 50 °C.

[0128] In some embodiments, including any of the foregoing, the set-point temperature is 600 °C.

[0129] In some embodiments, including any of the foregoing, the set-point temperature is 660 °C.

[0130] In some embodiments, including any of the foregoing, the set-point temperature is 50 °C to 800 °C; 200 °C to 800 °C; 300 °C to 700 °C; 350 °C to 600 °C; 350 °C to 500 °C; or 530 °C to 500 °C.

[0131] In some embodiments, including any of the foregoing, the process includes increasing the feed rate if O2 concentration is rising.

[0132] In some embodiments, including any of the foregoing, the process includes introducing N2 into the rotary kiln if O2 concentration is rising.

[0133] In some embodiments, including any of the foregoing, the battery scrap comprises at least one battery, battery module, battery pack, device comprising a battery, component thereof, or combinations thereof.

[0134] In some embodiments, including any of the foregoing, the atmosphere in the rotary kiln is a reducing atmosphere.

[0135] In some embodiments, including any of the foregoing, the maintaining comprises using steady-state reactions and no external heating.

[0136] In some embodiments, including any of the foregoing, the rotary kiln is a rotary kiln described herein. [0137] Also set forth herein is a non-transitory computer readable medium comprising program instructions for battery recycling that, when executed by an apparatus, cause the apparatus to perform at least one process described herein.

EXAMPLES

EXAMPLE 1 - RECYCLING Ni, Co, Li

[0138] A rotary kiln composed of a stainless-steel shell having an internal volume of 60 m³ with knife gate airlocks to feed battery materials into and out of the kiln was provided. The rotary kiln included controls for controlling the inner atmosphere.

3,000 kg/hr of battery materials was continuously fed into the kiln, which is rotating at 0.5 RPM. The kiln was indirectly heated using external electric heaters. The kiln’s internal temperature was maintained between 400 °C and 600 °C. At steady-state, minimal to no heater power was required to sustain temperatures in the kiln. An oxygen deficient atmosphere was maintained in the kiln, e.g. less than 2% by volume O2, through the generation of gases as batteries are pyrolyzed. The calcined batteries, after being removed from the kiln, were directly fed to a sized reduction process at 100 °C to 600 °C . Calcined batteries were size reduced and separated into various fractions, e.g. active material, ferrous rich, and nonferrous rich, also a different sizes. Greater than 90 % by weight of Ni, Co, Li was recovered.

EXAMPLE 2 - UNOXIDIZED ALUMINUM AND GRAPHITE/CARBON

[0139] The rotary kiln, in the above example, would be run such that a temperature below 660 °C is maintained, internally. The kiln atmosphere would be reducing and have less than 2% O2 by volume. These conditions would result in less than 30% of the aluminum in the feed from being oxidized. In addition, none of the aluminum would melt. In the size reduction process, unoxidized and unmelted aluminum would improve liberation and separation of the battery materials, such as, but not limited to, Ni, Co, Li, from Al and other elements. This would make downstream refining more efficient. By operating at these conditions, more than 90% of the graphite would remain not combusted and not oxidized. This would increase the yield of graphite sent to the powder fraction in the size reduction process. This would result in less heat released and less CO2 emissions. These conditions also would result in pyrolysis of plastics contained in the batteries. This would cause more carbon to be left in the solid phase. This would in turn reduce CO2 emissions and the energy release in the kiln. [0140] The embodiments and examples described above are intended to be merely illustrative and non-limiting. Those skilled in the art will recognize or will be able to ascertain using no more than routine experimentation, numerous equivalents of specific compounds, materials and procedures. All such equivalents are considered to be within the scope and are encompassed by the appended claims.

Claims

Claims

1. A rotary kiln, comprising: an inlet solid airlock; an outlet solid airlock; and a heater configured to indirectly heat the rotary kiln; wherein the rotary kiln is not lined with a refractory material.

2. The rotary kiln of claim 1, wherein the rotary kiln is lined with a metal, combination of metals, or an alloy thereof.

3. The rotary kiln of claim 1 or 2, wherein the rotary kiln is lined with stainless steel, carbon steel, or a combination thereof.

4. The rotary kiln of any one of claims 1-3, wherein the rotary kiln is coupled upstream to a feed conveyor and chute.

5. The rotary kiln of any one of claims 1-4, wherein the inlet solid airlock, outlet solid airlock, or both, is a knife-gate airlock or a rotary airlock.

6. The rotary kiln of any one of claims 1-5, wherein the rotary kiln is coupled downstream to a discharge chute and conveyor.

7. The rotary kiln of any one of claims 1-6, wherein the rotary kiln is coupled to an inert gas source that comprises a gas or liquid selected from the group consisting of N2, H2, CO2, Ar, or a combination thereof.

8. The rotary kiln of any one of claims 1-7, wherein the rotary kiln is coupled to a liquid nitrogen tank, liquid nitrogen vaporizer, or a combination thereof.

9. The rotary kiln of any one of claims 1-8, wherein the rotary kiln is coupled to a liquid nitrogen tank.

10. The rotary kiln of any one of claims 1-9, wherein the heater is an electrical heater.

11. The rotary kiln of any one of claims 1-10, wherein the rotary kiln further comprises a means for detecting blockages.

12. The rotary kiln of claim 11, wherein the means for detecting blockages are selected from cameras, electromagnetic sensors, and combinations thereof.

13. The rotary kiln of any one of claims 1-12, wherein the rotary kiln further comprises means for removing blockages.

14. The rotary kiln of claim 13, wherein the means for removing blockages are at least one actuated pusher plate.

15. The rotary kiln of any one of claims 1-14, wherein the rotary kiln is coupled, directly or indirectly, to at least one mechanical separator.

16. The rotary kiln of claim 15, wherein the mechanical separator comprises multiple devices for size reduction processes.

17. The rotary kiln of claim 16, wherein the mechanical separator comprises at least one device for size reduction selected from vibratory screener, magnetic separator, size reducer, or a combination thereof.

18. The rotary kiln of any one of claims 1-17, further comprising oxygen sensors, nitrogen sensors, humidity sensors, or a combination thereof.

19. The rotary kiln of any one of claims 1-18, further comprising oxygen sensors.

20. The rotary kiln of claim 19, wherein the oxygen sensors are disposed at the outlet of the kiln.

21. The rotary kiln of any one of claims 1-20, further comprising temperature sensors.

22. The rotary kiln of claim 21, wherein the temperature sensors are located in the rotary kiln.

23. The rotary kiln of claim 22, wherein the temperature sensors are located in the rotary kiln and are spaced apart.

24. The rotary kiln of claim 23, wherein the temperature sensors are located in the rotary kiln and spaced apart to determine temperature variations as a function of kiln length.

25. A process for producing calcined metal concentrate, comprising: continuously inputting battery scrap into a rotary kiln; calcining the battery scrap in the rotary kiln under a reducing atmosphere; and continuously outputting calcined metal concentrate out of the rotary kiln.

26. The process of claim 25, wherein the battery scrap comprises at least one battery', battery module, battery pack, device comprising a battery, component thereof, or combinations thereof.

27. The process of claim 25 or 26, wherein outputting calcined metal concentrate comprises conveying calcined metal concentrate out of the rotary' kiln.

28. The process of any one of claims 25-27, wherein the calcining occurs at 20 °C to 800 °C.

29. The process of any one of claims 25-28, wherein the calcining occurs at 200 °C to 800 °C.

30. The process of any one of claims 25-29, wherein the calcining occurs without external heating.

31. The process of any one of claims 25-30, wherein the calcining proceeds as at least one steady -state reaction.

32. The process of any one of claims 25-31, comprising adjusting a rate of continuously inputting, continuously outputting, or both, to achieve steady-state conditions.

33. The process of any one of claims 25-32, comprising reducing or eliminating indirect heating when the process is at steady-state conditions.

34. The process of any one of claims 25-33, comprising introducing nitrogen into the rotary kiln when the process is at steady-state conditions.

35. The process of any one of claims 25-34, wherein the calcined metal concentrate is not cooled actively.

36. The process of any one of claims 25-35, wherein the temperature of the calcined metal concentrate is 50 °C or greater.

37. The process of any one of claims 25-36, wherein the temperature of the calcined metal concentrate is 50 °C to 800 °C.

38. The process of any one of claims 25-37, further comprising continuously conveying calcined metal concentrate into a shredder, a mechanical separator, or a combination thereof.

39. The process of any one of claims 25-38, further comprising shredding the calcined metal concentrate at a temperature above room temperature.

40. The process of any one of claims 25-39, wherein the oxygen concentration in the rotary kiln is 0% to 10% by volume.

41. The process of any one of claims 25-40, wherein the oxygen concentration in the rotary kiln is less than 4% by volume.

42. The process of any one of claims 25-41, wherein the atmosphere in the rotary kiln further comprises an inert gas selected from N2, H2, CO2, Ar, and combinations thereof.

43. The process of any one of claims 25-42, wherein the calcined metal concentrate comprises aluminum metal, carbon, graphite, or a combination thereof.

44. The process of any one of claims 25-43, wherein the calcined metal concentrate comprises calcined batteries that comprise intact aluminum metal.

45. The process of any one of claims 25-44, wherein the calcined metal concentrate comprises more than 50% by mass of the graphite from the battery scrap.

46. The process of any one of claims 25-45, wherein the calcined metal concentrate comprises Ni, Co, Mn, Cu, Al, Li, or combinations thereof.

47. A process for producing calcined metal concentrate, comprising: continuously inputting battery scrap into a rotary kiln; heating, in a reducing atmosphere, the battery scrap until a steady-state reaction is achieved; reducing heating, stopping heating, or a combination thereof; and continuously outputting calcined metal concentrate out of the rotary kiln.

48. The process of claim 47, wherein the battery scrap comprises at least one battery, battery module, battery pack, device comprising a battery, component thereof, or combinations thereof.

49. The process of claim 47 or 48, wherein the heating is indirect electrical heating.

50. The process of any one of claims 47-49, wherein outputting calcined metal concentrate comprises conveying calcined metal concentrate out of the rotary kiln.

51. The process of any one of claims 47-50, wherein the steady-state reaction occurs at 20 °C to 800 °C.

52. The process of any one of claims 47-51, wherein the steady-state reaction occurs at 200 °C to 800 °C.

53. The process of any one of claims 47-52, wherein the steady-state reaction occurs without external heating.

54. The process of any one of claims 47-53, wherein the calcined metal concentrate is not cooled actively.

55. The process of any one of claims 47-54, wherein the calcined metal concentrate is at 50 °C or greater.

56. The process of any one of claims 47-55, wherein the temperature of the calcined metal concentrate is 200 °C to 800 °C.

57. The process of any one of claims 47-56, further comprising continuously conveying calcined metal concentrate into size reduction equipment, size separation equipment, equipment conveying material between other equipment, or a combination thereof.

58. The process of any one of claims 47-57, further comprising continuously conveying calcined metal concentrate into a shredder, a mechanical separator, or a combination thereof.

59. The process of any one of claims 47-58, further comprising shredding the calcined metal concentrate at a temperature above room temperature.

60. The process of any one of claims 47-59, wherein the oxygen concentration in the rotary kiln is 0% to 10% by volume.

61. The process of any one of claims 47-69, wherein the atmosphere in the rotary kiln has less than 4% by volume oxygen.

62. A process for producing calcined metal concentrate, comprising: continuously inputting battery scrap into a rotary kiln; maintaining in the rotary kiln a temperature of 200 °C to 800 °C, in a reducing atmosphere, using at least one steady-state reaction and no external heating; continuously outputting calcined metal concentrate out of the rotary kiln.

63. The process of claim 62, wherein the battery scrap comprises at least one battery', battery module, battery pack, device comprising a battery, component thereof, or combinations thereof

64. The process of claim 62 or 63, comprising maintaining in the rotary kiln a temperature less than 660 °C.

65. The process of any one of claims 62-64, comprising maintaining in the rotary kiln a temperature less than 400 °C.

66. The process of any one of claims 62-65, wherein the outputting calcined metal concentrate comprises conveying calcined metal concentrate out of the rotary kiln.

67. The process of any one of claims 62-66, wherein the steady-state reaction occurs at 200 °C to 800 °C; 300 °C to 700 °C; 350 °C to 600 °C; 350 °C to 500 °C; or 530 °C to 500 °C.

68. The process of any one of claims 62-67, wherein the calcined metal concentrate is not cooled.

69. The process of any one of claims 62-68, wherein the temperature of the calcined metal concentrate is 50 °C or greater.

70. The process of any one of claims 62-69, wherein the temperature of the calcined metal concentrate is 200 °C to 800 °C.

71. The process of any one of claims 62-70, further comprising continuously conveying calcined metal concentrate into a shredder, a mechanical separator, or a combination thereof.

72. The process of any one of claims 62-71, further comprising shredding the calcined metal concentrate at a temperature above room temperature.

73. The process of any one of claims 62-72, wherein the oxygen concentration in the rotary kiln is 0% to 10% by volume.

74. The process of any one of claims 62-73, wherein the atmosphere in the rotary kiln has less than 4% by volume oxygen.

75. A process for producing calcined metal concentrate, comprising: continuously inputting battery scrap into a rotary kiln; maintaining in the rotary kiln a set-point temperature using a feedback loop by modulating one or more members selected from (a) through (1):

(a) heat applied to the rotary kiln;

(b) temperature inside the rotary kiln;

(c) O2 concentration in the rotaiy kiln or outlet;

(d) N2 concentration in the rotary kiln or outlet;

(e) rotary kiln rotation rate;

(f) bed height in the rotary kiln;

(g) residence time in the rotary kiln;

(h) rate of material input (feed rate) into the rotary kiln;

(i) feed type based on contained energy;

(j) feed type based on form factor;

(k) rate of material output out of the rotary kiln; or

(l) a combination of (a), (b), (c), (d), (e), (f), (g), (h), (i), (j), or (k); and continuously outputting calcined metal concentrate out of the rotary kiln.

76. The process of claim 75, comprising reducing heating if the temperature in the rotary kiln exceeds the set-point temperature.

77. The process of claim 75 or 76, wherein the set-point temperature is at least 50 °C.

78. The process of any one of claims 75-77, wherein the set-point temperature is 50 °C to 800 °C; 200 °C to 800 °C; 300 °C to 700 °C; 350 °C to 600 °C; 350 °C to 500 °C; or 530 °C to

500 °C.

79. The process of any one of claims 75-78, comprising increasing the feed rate if O2 concentration is rising.

80. The process of any one of claims 75-79, comprising introducing N2 into the rotary kiln if O2 concentration is rising.

81. The process any one of claims 75-80, wherein the battery scrap comprises at least one battery, battery module, battery pack, device comprising a battery, component thereof, or combinations thereof.

82. The process of any one of claims 75-81, wherein the atmosphere in the rotary kiln is a reducing atmosphere.

83. The process of any one of claims 75-82, wherein the maintaining comprises using steady -state reactions and no external heating.

84. The process of any one of claims 25-83, wherein the rotary kiln is a rotary kiln of any one of claims 1-24.

85. A non-transitory computer readable medium comprising program instructions for battery recycling that, when executed by an apparatus, cause the apparatus to perform at least a process of any one of claims 25-83.