Processing black mass

Abstract

The present invention concerns processing methods for feeding black mass in a pyrometallurgical furnace. Black mass is a powder containing high concentrations of valuable metals such as Ni and / or Co. The present invention is related to conditioning, feeding and smelting black mass. The black mass is smelted in the furnace under reducing conditions at high temperature, thereby forming a liquid bath with an alloy phase and a slag phase. During feeding and smelting of conditioned black mass, the total dust concentration above the liquid bath is 1.5 mg / m3 or less.

Description

[0001] Processing black mass

[0002] The present invention is in the field of pyrometallurgy and concerns the recovery of valuable metals from lithium-ion batteries or their waste. More specifically, the invention provides a process for recovering Ni and / or Co from black mass, wherein the black mass is specifically conditioned before feeding it into a pyrometallurgical furnace.

[0003] In recent years electric vehicles have seen an unprecedented growth, among others driven by new legislations in Europe and China, designed to gradually reduce the CO2 footprint of the car fleets and to limit the air pollution. This growth is expected to continue. The adoption of electric vehicles greatly depends on the performance of the batteries used to store electrical energy. To obtain the highest energy density while keeping the costs under control, currently most of all Li-ion batteries are used. Many of these batteries contain cathodes based on the transition metals Ni, Mn and Co, and are therefore also known as NMC batteries. With the growth of the electric mobility market, also the demand for these metals is expected to increase significantly.

[0004] The demand for Ni and Co may even surpass the present worldwide production capacity. Co is particularly critical as it is today only produced as a byproduct of the Ni and Cu industry. The Ni market is significantly larger than the Co market. Most of the Ni goes to the production of stainless steel, where purity is relatively unimportant. High purity Ni and Co metals or compounds are however already in short supply. In view of the above, recovering Ni and Co from end-of-life batteries is an attractive proposal.

[0005] Smelting processes have been proposed allowing for the recovery of metals from waste batteries. Such processes typically result in the production of an alloy and a slag. Valuable metals collected in the alloy, if sufficiently pure, may be suitable e.g. for the preparation of cathode materials for Li-ion batteries. The slag, if sufficiently depleted in heavy metals, may be suitable for use in the construction industry, or for safe disposal.

[0006] Such smelting processes allow to use complete packs, modules or cells of Li-ion batteries as feeding materials. This type of feed is often referred to as “direct feed”.

[0007] Alternatively, so-called "Black Mass" (BM), "Black Matter" or “Black Powder” is a very interesting starting material for recycling via smelting processes. The expression "Black Mass" is typically used in industry to describe an intermediate product originating from Li-ion batteries or their waste, such as new or waste Li-ion batteries, spent or end-of-life batteries, production or battery scrap, electrode materials or other pre-processed battery materials. It is thus clear that while the expression Black Mass is frequently used in industry, the exact composition and shape of these materials may vary significantly, depending on producer or application.

[0008] Typically, end-of-life batteries are dismantled and shredded, which may include separation of casing materials, foils and / or anodes. Sometimes they are also pre-processed. Black Mass obtained from such processes has usually a relatively low Al content, as compared to the treatment of complete batteries. On the other hand, it can contain rather high amounts of Li, Mn, Co and / or Ni, which makes the pyrometallurgical process economically interesting. However, black mass may further contain hazardous components (e.g. other heavy metals, flammable organics), and its fine particle size may lead to Environmental, Health and Safety (EHS) issues during handling and processing. Nevertheless, black mass has become a material with increasing importance and volume in the battery recycling market.

[0009] The recovery of the valuable metals from powders of black mass via smelting processes thus poses challenges: Depending on the used method(s) of pre-treatment, the feeding materials may contain up to 50 wt% of carbon, for example in the form of fine graphite particles, which may lead to dust release when feeding the furnace from the top, supplying the black mass from above the liquid bath. Depending on the production process, these black mass materials may also contain certain amounts of flammable hydrocarbons or aluminum powders. Therefore, they may pose explosion risks and fire hazards, particularly when they are not injected directly into the liquid bath.

[0010] In addition to EHS issues, loose powder is prone to entrainment (drag-out) to the off-take zone or gas cleaning system of a furnace in metallurgical processes. This results in losses of valuable metals, unless energy-intensive recycling streams are employed for (flue) dust treatment.

[0011] These EHS issues and entrainment problems are especially apparent when feeding black mass from the top into a furnace equipped with submerged injection of O2 bearing gas, due to the large volume of gas flowing upwards from the liquid bath.

[0012] Mousa et al. (Effect of graphite on the recovery of valuable metals from spent Li-ion batteries in baths of hot metal and steel. Recycling 7, 5, 2022 doi: 10.3390 / recycling7010005) produced briquettes of black mass by using a hydraulic press with a stainless steel mould (<D = 7 cm), and studied the metal recovery in a carbon-saturated hot metal bath (95.67% Fe) or steel bath (98.25 % Fe). When briquettes containing graphite were used for smelting reduction under an inert atmosphere in a hot metal bath, the maximum recovery rate in the alloy phase was 71 .7% for Ni and 62.3% for Co. The recovery rate of these metals was negatively impacted by the fact that excess graphite floated on the upper surface of the hot metal: This restricted the complete reduction of the metal oxides. Therefore, rather than using briquettes, it is recommended by the authors to either separate graphite from the black mass before the smelting process, or to inject the black mass powder directly into the molten bath.

[0013] Sommerfeld et al. (A Combined Pyro- and Hydrometallurgical Approach to Recycle Pyrolyzed Lithium-ion Battery Black Mass Part 1 : Production of Lithium Concentrates in an Electric Arc Furnace. Metals 2020, 10, 1069; doi :10.3390 / met10081069) made pellets starting from a fine fraction (< 100 pm) of black mass and performed smelt reduction tests of the pellets in lab scale furnaces. The yield based on the metal input was 93.3 % for Ni and the yield for Co was 81.6%. A considerable weight loss was observed and mainly attributed to dust consumed by the off-gas system before the material could react with the molten metal or slag phase. The black mass was charged in the turbulent zone of the furnace so that losses due to dusting of the input material occurred.

[0014] Hu et al. (Recovery of Co, Ni, Mn and Li from Li-ion batteries by smelting reduction - Part II: A pilotscale demonstration. Journal of Power Sources 483 (2021) 229089, doi: 10.1016 / j.jpowsour.2020.229089) carried out reduction tests of black mass in a large electric arc furnace, where black mass was either charged into the furnace by top feeding or through a submerged injection lance, which is a method only suitable for injection of materials with good flowability. Specifically the dust fraction with a D90 of 0.125 pm obtained during black mass sieving, was injected via submerged injection due to its fineness. During the submerged injection process excessive foaming of the slag occurred.

[0015] It is therefore an objective of the present invention to provide a more efficient feeding method for black mass into a furnace, resulting in higher metal yields, thereby also minimizing negative effects such as dust formation, entrainment or foaming.

[0016] The present invention concerns a process to address the previously mentioned issues and problems of the prior art by modifying the way in which black mass is conditioned, fed into a furnace and smelted. In a first aspect, the current invention describes a process for recovering Ni and / or Co from black mass, further containing Li, the process comprising the steps of:

[0017] - conditioning the black mass;

[0018] - feeding the black mass into a furnace;

[0019] - smelting the black mass under reducing conditions, thereby forming a liquid bath with an alloy phase containing more than 80% of at least one of Ni or Co, and a Li-containing slag phase; and,

[0020] - separating the alloy phase and the slag phase;

[0021] wherein a total dust concentration above the liquid bath is 1.5 mg / m^ or less, preferably 1.0 mg / m^ or less, more preferably 0.5 mg / m^ or less.

[0022] In the context of this invention, “black mass” is defined as a powder obtained from Li-ion battery materials or their waste, which contains appreciable amounts of Co and / or Ni.

[0023] “Li-ion batteries or their waste” are, for example, new or waste Li-ion batteries, spent or end-of-life batteries, production or battery scrap, electrode materials or pre-processed battery materials, such as after shredding or sorting. For example, black mass may be produced through shredding and separation of pyrolyzed end of life (EOL) lithium-ion batteries, or in another example through shredding EOL lithium-ion batteries with water, followed by drying and separation, or in another example by shredding and separation of production scrap of lithium-ion batteries.

[0024] Black mass typically contains the majority of the cathode materials and anode materials of the batteries, together with fractions of other battery components. The resulting black mass is typically a fine, often black, powder material.

[0025] Black mass typically contains the valuable metals cobalt and / or nickel in a more concentrated form, especially when for example casing materials have been removed upfront. Therefore, one advantage of black mass as starting material compared to a “direct feed” (of modules, cells etc.) is that the amount of slag phase produced per unit of metal produced is reduced.

[0026] In a further aspect, the black mass contains 0 wt% to 40 wt% Ni based on the dry weight of the black mass. Black mass typically does not contain Ni when it is obtained from lithium cobalt oxide (LCO) type batteries.

[0027] In a further aspect, the black mass contains 0 wt% to 40 wt% Co based on the dry weight of the black mass. Black mass typically does not contain Co when obtained from nickel metal hydride (NiMH) type batteries. Other examples are the black mass obtained from nickel-iron or nickel-manganese type batteries.

[0028] In a further aspect, the black mass contains both Ni and Co. An example is the black mass obtained from nickel-manganese-cobalt (NMC) type batteries.

[0029] Black mass may further comprise Cu, Mn, Al and C.

[0030] Pre-processing of black mass may lead to black mass types with low Cu, Al and C content.

[0031] In a further aspect, the black mass contains 0 wt% to 10 wt% Al based on the dry weight of the black mass. Al is for example separated from black mass through density separation techniques or pyrolysis. In a further aspect, the black mass contains 2 wt% to 10 wt% Li based on the dry weight of the black mass.

[0032] In a further aspect, the black mass contains 0 wt% to 40 wt% Mn based on the dry weight of the black mass. Black mass typically contains no Mn when obtained from batteries that employ lithium cobalt oxide (LCO) or lithium cobalt nickel aluminium oxide (NCA) as cathode materials.

[0033] In a further aspect, the black mass contains 0 wt% to 10 wt% Cu based on the dry weight of the black mass. Cu is beneficial for creating a Ni-Co-Cu alloy.

[0034] According to the first aspect of the invention, black mass is conditioned, both to protect the working environment and to maximize the recovery of the contained valuable metals. Conditioning serves, among others, the purpose to treat the black mass so that it is not fed into the furnace as a fine, loose powder. The conditioning may include, but is not limited to mechanical, thermal, chemical conditioning, surface modification or moisture conditioning. Examples of conditioning include compacting, extruding, agglomerating, drying, pelletizing, granulating, blending, wetting, packaging, coating, addition of surfactants or heat treatment.

[0035] In a further aspect, the conditioning of the black mass is packaging. This limits the dust release issue of black mass (powder) feeding. Packaging black mass is a preferred conditioning method as not compromising the total yield, while minimizing or avoiding EHS issues. The black mass characteristics to enable packaging are not stringent, allowing to treat a large variety of different types of black mass available on the market. Moreover, this conditioning method allows black mass to be fed more efficient and more complete from the top opening of the furnace (feeding port), making the feeding process generally more flexible.

[0036] In a further aspect, the current invention describes a process for recovering Ni and / or Co from black mass, further containing Li, the process comprising the steps of:

[0037] - conditioning the black mass;

[0038] - feeding the black mass into a pyrometallurgical furnace;

[0039] - smelting the black mass under reducing conditions, thereby forming a liquid bath with an alloy phase containing more than 80% of at least one of Ni or Co, and a Li-containing slag phase; and,

[0040] - separating the alloy phase and the slag phase;

[0041] wherein a total dust concentration above the liquid bath is 1.5 mg / m^ or less, and, wherein conditioning comprises packaging.

[0042] In the context of this invention, the terms packaging, packing, wrapping, covering and casing are considered equivalent. If the selected conditioning method is packaging, this means that the powder is provided to the furnace for example in a bag, container, pouch, sachet or envelope.

[0043] Different commonly known types of furnaces suitable for smelting a charge, such as black mass with or without fluxing agents, at high temperature can be used. For example, electric furnaces are particularly suitable when high temperatures are desired. It is understood that the above methods are independent of the furnace type used.

[0044] According to the first aspect of the invention, the conditioned black mass is fed to the furnace, and smelted under reducing conditions, preferably strong reducing conditions, in order to recover Ni and Co, if present, in the alloy phase of the liquid bath. It is advantageous if the black mass is fed to a furnace already containing a molten bath.

[0045] Conditioning is especially advantageous for black mass containing carbon. Even high amounts of carbon can be handled by the present invention. Carbon, typically graphite, has a higher tendency for entrainment compared to other particles in the black mass, as it is quite typically in the form of a fine powder and also lighter than metal-containing particles of the same size. By conditioning, also carryover of black mass due to explosive reactions of carbon with Oz at high temperature can be avoided. In a further aspect, the black mass has a carbon content of 0 to 50 wt% (based on the dry weight of the black mass).

[0046] In black mass with a carbon content of more than 50 wt%, such as (in wt%) 60%, 70%, 80% or 90%, the Co and / or Ni content would become too low to be industrially interesting. Moreover, if the carbon content would be too high, this does not correspond to a black mass from battery recycling anymore, even of the present invention could handle it.

[0047] Carbon (e.g. graphite) may be separated of black mass through flotation. Using black mass with high carbon content as a feed is beneficial for the process according to the current invention in terms of the energy balance: Carbon contained in black mass can replace at least part of the fuel for smelting.

[0048] Among the different types of black mass on the market, a wide variety in the carbon content has been observed, such as (in wt%) 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% or 45%, mainly dependent on the preparation method of the black mass and the type of material used to make the specific black mass. For example, when the material is from cathode scrap, or when the preparation method includes a pyrotreatment, the amount of carbon in the resulting black mass can be very low or even zero.

[0049] Moreover, Li-ion batteries seem to evolve from C-anodes to Si-C anodes, and eventually even to C-free anodes. Especially in the latter case, also the amount of carbon in the resulting black mass can be very low or even zero.

[0050] In a further aspect, the smelting under reducing conditions is performed at a p©2 of 10‘7to 10’1 preferably 10‘7-5to 10’1®-5, more preferably 10’® to 10’1^ atm. Operating the smelting process at a pO in this range enables an optimal balance between maximizing metal yields, for which lower pO levels are beneficial, and ensuring an efficient contribution of battery materials to the energy balance, for which higher pC>2 levels are beneficial. For example, the contribution to the energy balance of carbon, optionally contained in black mass, can be advantageously modulated by the partial pressure of oxygen (PO2): In conditions with higher oxidizing potential, the CO2 / CO ratio, and consequently the generated heat, will be increased, thus reducing the need for additional fuel to run the process.

[0051] According to the first aspect of the invention, by reductive smelting a liquid bath is formed with an alloy phase containing more than 80% of at least one of Ni or Co fed to the furnace, preferably more than 90%, more preferably more than 95%. The percentages herein are understood as “weight percent” (wt%).

[0052] According to the first aspect of the invention, the process comprises a step of separating the alloy phase and the slag phase. Preferably, this is executed by tapping off the liquid phases from the furnace. Alternatively, the step of separating the alloy phase and the slag phase is executed after cooling and solidification by mechanical means, such as cutting.

[0053] In a further aspect, the black mass contains both Ni and Co, and the resulting alloy phase after smelting contains more than 80 % of Ni and more than 80% of Co fed to the furnace, preferably more than 90 % of each of Ni and Co, more preferably more than 95 % of each of Ni and Co.

[0054] The high yields reflect the smelting reducing conditions, and the fact that nearly all Ni and / or Co metals contained in the black mass introduced to the furnace, actually reached the liquid bath to react, demonstrating the efficiency of the applied conditioning methods according to the present invention. The operating temperature for the step of smelting is 1350°C to 1600°C, preferably 1450°C to 1550°C. In view of energy savings, the operating temperature is chosen as low as possible, but higher than a minimum temperature to ensure the liquid bath is in a fully molten state.

[0055] In a further aspect, the furnace is operated at atmospheric pressure or slightly sub-atmospheric pressure.

[0056] In a further aspect, so-called “slag formers” or “fluxing agents” are provided to the furnace upfront, and / or fed together with the black mass. By “slag formers” are meant: one or more of for example CaO, AI2O3 and SIO2- Other slag formers, well known to the skilled person, may also be present. The slag forming compounds may be added as such, or they may be obtained in situ from easily oxidized metals present in the charge, such as aluminium.

[0057] In a further aspect of the current invention, SiO2, CaO and AI2O3 are present in the slag phase. The slag system primarily, but not exclusively, consists of AI2O3, CaO, SiO2, MnO, and U2O. The concentrations of AI2O3, MnO, and IJ2O are determined by the feed composition.

[0058] In a further aspect, the slag phase has a SIO2 / (CaO+ AI2O3 + SiO2) ratio of 0.40 or less, preferably 0.30 or less, more preferably 0.20 or less.

[0059] SIO2 impurities are commonly present in calcium-based fluxing agents such as limestone, a sedimentary rock primarily composed of calcium carbonate (CaCOg) that is commonly utilized as an economical source of calcium in pyrometallurgical applications. Therefore, when using limestone, the above ratio will typically not be zero, but 0.01 or more.

[0060] When the ratio of SiO2 / (CaO+ AI2O3 + SiO2) gets lower, less slag is produced, which is industrially and environmentally advantageous. The higher the ratio, the more slag is produced, which has an environmental impact (slag disposal) as well as a cost, and may also lead to increased metal losses. In a further aspect, the slag phase has a A^Og^CaO + AI2O3 + SIO2> ratio between 0.30 and 0.70, more preferred between 0.35 and 0.65, and most preferred between 0.40 and 0.60.

[0061] In a further aspect, the slag phase has a CaO / (CaO + AI2O3 + SIO2) ratio between 0.10 and 0.55, more preferred between 0.15 and 0.50, and most preferred between 0.20 and 0.45.

[0062] These compositional ranges for the slag enable to minimize the produced volumes of slag, while maintaining the slag in liquid form within the operating temperature of smelting. The exact slag composition is chosen depending on the feed composition. Using these guidelines, the skilled person will also easily obtain a slag having a sufficiently low viscosity at the operating temperature to allow for decantation and separation of the formed phases (alloy and slag).

[0063] Upon smelting the black mass, a Li-containing slag phase is formed. Under the conditions of the present invention, lithium contained in the black mass will almost quantitatively report to the slag phase. Also manganese, optionally present in black mass, will report almost quantitatively to the slag phase under these conditions. It is understood that “almost quantitative” refers to the distribution of lithium between the slag phase and the alloy phase, thus not taking into account any dust-to-dust transfer, or fuming of lithium from the slag phase during the process.

[0064] It is common practice to determine the particle size distribution of powders, such as black mass, using laser diffraction. Black mass available on the market typically has a D50 ranging from 10 to 300 pm, or 10 to 100 pm, or 10 to 50 pm. The present process is independent of the type of black mass, but is most advantageous if the particle size is within these ranges.

[0065] The dust concentrations referred to in the context of this invention are measured above the liquid bath, typically at the feeding port. In the context, “at the feeding port” means in a radius of 1 m around the feeding port.

[0066] In the context of this invention, “dust concentration” and “particulate matter (PM) concentration” above the liquid bath are used interchangeably. These terms are used to indicate the concentration of fine particles present in air. They refer to the mass of particulate matter per unit volume of air, typically expressed in pg / m^ or mg / ir In the context of this invention, the dust concentration is the average concentration that is measured during a period of continuously feeding black mass above the liquid bath, typically at the feeding port.

[0067] In general, dust particles with a size up to 100 micron are often referred to as “inhalable dust”.

[0068] For example, ISO 16000-34:2018, a standard for inhalable dust particles, covers particles with a size range from approximately 1 nm to 100 pm. The standard defines sampling conventions for particle size fractions used in assessing possible health effects of airborne particles in the workplace and ambient environment.

[0069] In the context of this invention, the “total dust concentration” or “total particulate matter concentration” refers to the concentration of particles with a diameter smaller than or equal to about 15 pm, which is to be understood not limiting, but reflects the detection limit of the device used for measuring the total dust concentration.

[0070] It is standard practice in industry to measure “total dust concentration” with standard instruments, such as real-time aerosol monitors, for example with a DustTrak™ DRX Aerosol Monitor. A DustTrak™ DRX Aerosol Monitor measures the concentrations of particles from about 0.1 micron to about 15 micron, and is calibrated by the manufacturer against a reference photometer (Model 8587) that is gravi metrically calibrated to ISO 12103-1 , A1 test dust (Arizona Test Dust).

[0071] Other suitable devices for dust measurement may have a different detection limits, which are then reported as “total dust”, for example including particles up to 30 micron. However, typically all instruments are very capable of measuring various sizes of small-diameter particulate matter (PM1 , PM2.5, PM4, PM10).

[0072] The terms PM1 , PM2.5, PM4, PM10, also used herein, refer to a specific particle size. Namely, the term PM1 indicates particles with diameter of 1 pm or less. PM2.5 indicates particles with diameter of 2.5 pm or less. PM4 indicates particles with diameter of 4 pm or less. PM10 indicates particles with diameter of 10 pm or less.

[0073] In a further aspect, the dust concentration above the liquid bath is 1.5 mg / m^ or less, preferably 0.25 mg / m3 or less, most preferably 0.10 mg / m^ or less., wherein said dust concentration refers to particles with a diameter of 10 pm or less (= PM10 concentration).

[0074] In a further aspect, the PM4 concentration above the liquid bath is 1 .5 mg / m^ or less, preferably 0.25 mg / m3 or less, most preferably 0.10 mg / m^ or less.

[0075] In a further aspect, the PM2.5 concentration above the liquid bath is 1 .5 mg / m^ or less, preferably 0.25 mg / m3 or less, most preferably 0.10 mg / m^ or less.

[0076] In a further aspect, the PM1 concentration above the liquid bath is 1 .5 mg / m3 or less, preferably 0.25 mg / m^ or less, most preferably 0.10 mg / m^ or less.

[0077] In case of black mass, the most preferred values for PM10, PM4, PM2.5 or PM1 would allow a process, in which a potential release of Ni , Co and Mn to the environment should likely be below occupational exposure limits (OELs).

[0078] Values around the preferred 0.25 mg / m^ might bring emission values potentially rather close to the OELs, so that there is an incentive to stay preferably below that value.

[0079] The term “dust” refers to a particle concentration above the liquid bath, typically at the feeding port, which is mainly originating from unreacted black mass, meaning a concentration of black mass particles, which did not or not yet reach the liquid bath.

[0080] It is understood that the dust concentration according to the first aspect and subsequent aspects above is different from so-called “flue dust”, which is often mentioned in the context of pyrometallurgical furnaces.

[0081] Flue dust is typically collected in the so-called off-take zone or gas cleaning system of a furnace. All types of equipment can be installed in the off-take zone, such as a dust-catcher, baghouse filter, cyclone separator, electrostatic precipitator, scrubber, Venturi scrubber or condenser. Alternatively, parts of the off-take zone can be named by a specific function rather than by referring to a specific equipment, for example cooling zone (cooling section), condensation zone (condensation section) or the like.

[0082] Dust originating from the feeding process may be carried over to this off-take zone and form part of the flue dust, especially when none of the advantageous conditioning methods of the present invention is applied. This can thus also be described as “dust-to-dust transfer”. Particles of the feeding material, such as dust of metal containing black mass particles and / or carbon particles, are transferred (essentially unreacted) to the flue dust. If the flue dust contains significant amounts of Ni or Co, this is an indication for a higher dust-to-dust transfer of unreacted black mass. If the flue dust contains almost no Ni and / or Co this is an indication of a lower dust-to-dust transfer and indication that almost all Ni and / or Co reacted in the bath.

[0083] In a further aspect, the slag phase has a Ca / AI ratio of 3.2 or less, preferably 2.0 or less, more preferably 1.5 or less.

[0084] When the ratio of Ca / AI gets lower, less slag is produced, which is industrially and environmentally advantageous. The higher the ratio, the more slag is produced.

[0085] Slags with a Ca / AI ratio of less than 0.15 typically have a too high liquidus temperatures, such as 1600°C or more, which is disadvantageous for the present process, as smelting requires more energy. Therefore, the Ca / AI ratio is preferably 0.15 or more.

[0086] Therefore, in a further aspect, a dust-to-dust transfer of Ni and / or Co from feed material to the off-take zone or gas cleaning system of the furnace is less than 20%, preferably less than 10%, most preferably less than 5%.

[0087] Reducing the dust to dust transfer, for example by applying any of the conditioning methods of the present invention, minimizes the need for energy-intensive recycling of flue dust. Overall low values of Ni and / or Co in the flue dust, such as 20%, 10%, 5%, 3% or even 1% are an indication of efficient conditioning, resulting in high metal recovery rates in the alloy phase.

[0088] Flue dust may thus comprise unreacted black mass from dust-to-dust transfer, but may additionally comprise particles originating from fuming processes out of the liquid bath.

[0089] In a further aspect, the feeding is continuous.

[0090] In the present setup, the total amount of black mass is added continuously to the furnace over a period of 30 to 120 minutes, optionally followed by a period of 30 to 60 minutes to allow complete reaction. The difference in time for feeding is mainly caused by the total amount of black mass that needs to be added.

[0091] Conditioned Black mass allows a more uniform and continuous addition via the feeding port as compared to direct feeds, which results in a more uniform CO2 release. This advantageously enhances both the stability of the pyrometallurgical process and the efficiency of successive carbon capture units. In a further aspect, the black mass before the step of conditioning has a moisture content of 0 to 30 wt% or 5 to 25 wt% or 5 to 15 wt% or 15 to 25 wt%.

[0092] The moisture content of black mass is determined by measuring the weight loss of a sample after heating to 120°C for 30-40 min.

[0093] In a further aspect, the conditioning is packaging, and the packaging comprises the steps of: providing a bag made of a material comprising a metallic material, paper or plastic; filling the bag with black mass; and, subsequently sealing the bag. The advantage of packaging black mass is to delay ignition until the packaged material reaches the liquid bath, thereby allowing that the reaction predominantly occurs in a submerged state. This approach minimizes dust formation and dust-to-dust transfer.

[0094] The advantage of packaging black mass is to delay ignition and to facilitate that the packaged material reaches the liquid bath. This approach minimizes dust formation and dust-to-dust transfer. Preferably, it also allows that more of the black mass reacts in a submerged state.

[0095] In a further aspect, the black mass is provided in bags of 0.5 to 10 kg, preferably 5 to 10 kg.

[0096] In a further aspect, air is removed from the bag before sealing.

[0097] This helps to prevent package bursting due to volume expansion of air at high temperatures.

[0098] In a further aspect, air is withdrawn from the bag by applying a vacuum.

[0099] A preference for metal packaging is attributed to a higher resistance at high temperatures compared to paper and plastic, allowing the packaged black mass to reach the molten bath without bursting or burning of the packaging material already above the molten bath, potentially increasing dust release. In a further aspect, the metallic material is aluminium.

[0100] The slag system of the present invention typically contains Al. Al bags are a preferred option due to their advantageous properties under reducing conditions, typically applied for the recovery of copper (Cu), nickel (N I), and cobalt (Co). In case black mass contains Al, it will report to the slag under the applied smelting conditions. Thus, by using Al bags, a contamination with metals formerly not present is avoided, this way also facilitating subsequent purification processes.

[0101] In a further aspect, the packaging material is Al and during or after smelting, calcium-containing halides are added to the slag, in order to fume out Li from the slag to collect Li via the flue dust. In this reaction, Ca atoms replace Li in the slag. The increased Al content of the black mass packaged in aluminum allows to add more Ca-containing halides to the slag, while still keeping the slag in a liquid state, and therefore to recover more Li in the flue dust.

[0102] In a further aspect, the total amount of fuel for the smelting process is decreased by feeding black mass packed in Al bags. Smelting black mass under reducing conditions may be an endothermic process, namely in case that the used black mass contains only minor amounts of Al and / or C. In that case, fuel must be added during the process to keep the operating temperature stable while feeding black mass. However, the Al packaging increases the Al content of the process, which may lower the required energy input for smelting.

[0103] In a further aspect, the smelting under reducing conditions is autogenous.

[0104] “Autogenous” refers to a process, wherein the feed material contains sufficient exothermic energy to sustain the process temperature without the need for additional fuel or electrical energy. This can advantageously be achieved by using black mass types with a high content of combustible materials, such as aluminium, carbon or plastics. In a further aspect, the feeding is conducted from the top of the furnace.

[0105] In a further aspect, top-feeding is conducted without the use of a carrier gas.

[0106] By “top-feeding” or “feeding from the top of the furnace” is meant that the feed is supplied from above the liquid bath. In this invention, top-feeding is preferred, as it requires less stringent powder quality (of the black mass) and can optionally provide an operational benefit by eliminating the need for carrier gas injection.

[0107] This is contrary to a submerged injection. Submerged injection is identified as a method mainly suitable for the processing of black mass powders with optimal flowability characteristics. Injection systems are often poorly adaptable to feed variability in size and particle size distribution (PSD), which can result in obstructions (such as cloaking) and operational downtimes, further complicating the recycling process. Given the current heterogeneity in black mass production techniques (e.g. pyrolysis, dry shredding or wet shredding) the applicability of this method is limited to a subset of the black mass available in the market. Furthermore, foaming is a significant issue with submerged injection. Since foaming is directly proportional to gas formation (either from gas blowing or reactions), this unwanted effect can be avoided by top-feeding according to the invention, preferably by top-feeding without blowing gas.

[0108] In a further aspect, the process further comprises a step of fuming of lithium from the liquid bath. Typically this is done by the addition of alkali or earth alkali halides, preferably chlorides, after smelting the black mass.

[0109] Part of the Li can fume out of the liquid bath, typically out of the slag phase, and thus be present in formed flue dust.

[0110] During pyrometallurgical processes, changes in bath height can serve as an indirect indicator of the dust concentration above the liquid bath during feeding. Although the bath height measurement does not directly measure dust-to-dust transfer to the flue fust, nor the dust concentration at the feeding port, it can be used to compare different conditioning methods of similar black mass feeds. The furnace may be equipped with a sensor capable of monitoring the bath height over time. Pyrometallurgical processes exhibit bath height fluctuations due to gas release during smelting feed materials. Higher fluctuations and changes in the bath hight during continuous feeding imply that more black mass is reaching the liquid bath, and more black mass is smelted. This results in more gas generation and more bath foaming. Consequently, a lower dust concentrations above the liquid bath and a lower dust-to-dust transfer is observed. Minimal bath fluctuations, on the other hand, hint for a higher total dust concentrations above the liquid bath, and a potentially higher dust-to-dust transfer.

[0111] While this method is less precise than direct measurements of the dust concentration around the feeding port, it nevertheless gives a fast indication of the efficiency of a chosen feeding method. For example, differences between feeding a loose powder of BM, and feeding BM after applying any one of the above-mentioned conditioning methods are demonstrated in the examples.

[0112] In a further aspect, an 02-bearing gas is introduced into the liquid bath by submerged injection. This is advantageous, as it allows sufficient mixing of the molten bath by the injected gas, this way improving reaction kinetics. An 02-bearing gas also helps to consume excess carbon (if present) beyond what is needed to reduce for example Ni or Co.

[0113] The following illustrates the invention.

[0114] Different black mass samples, with compositions and particles sizes specified in the Table 1 , were used to assess the impact of different conditioning methods of black mass on metal recovery and dust formation. The particle size of the black mass samples was determined by laser diffraction using a HELOS (H1920) particle size analyzer.

[0115] BM type 1 was produced through shredding and separation of pyrolyzed end of life (EOL) lithium-ion batteries. BM type 1 initially is in the form of a (fine) powder with a D50 of 50 pm.

[0116] BM type 2 was produced through shredding EOL lithium-ion batteries with water, followed by drying and separation. BM type 2 initially is in the form of a (fine) powder with a D50 of 95 pm.

[0117] Table 1 : Black mass types used

[0118] Name Composition (wt%) of dried BM Particle size (pm)

[0119] Cu Ni Co Fe Mn Al Li C F P D50 D90 BM Type 1 2.2 13,5 13.8 0.9 9.1 3.2 4.4 25.4 2.7 0.5 50 430

[0120] BM Type 2 10.3 10,0 5.7 0.3 15.3 4.7 3.1 22.5 2.1 0.3 95 305

[0121]

[0122] Experiments were conducted in a cylindrical reactor with a total volume of 1 m^, lined with refractory bricks. Natural gas and oxygen were injected in specific ratios to provide the necessary energy and achieve the desired partial pressure of oxygen (pO2) for effective metal separation. Gas flow rates were regulated based on temperature measurements and slag sample elemental analyses, and maintained within the range of 10 - 20 Nm^ / h for natural gas and 32 - 46 Nm^ / h for oxygen.

[0123] Example: Packaging of black mass

[0124] In this example, black mass type 1 was used.

[0125] Four different packaging materials were tested for this black mass type 1 powder, namely (1 ) iron cans, (2) aluminum bags, (3) plastic bags, and (4) paper bags.

[0126] The iron cans were filled with 500 g of BM type 1 and compressed to expel air from the cans.

[0127] The Al bags had a size of around 15 x 20 cm and a weight of around 100 g. They were composed with two layers of polyethylene and one layer of Al foil. They were filled with 500 g of BM type 1 , had most of the air pushed out and were heat-sealed.

[0128] The plastic bags and paper bags were filled, and had as much air as possible expelled and were then sealed using standard duct tape. In different tests, each of the this way conditioned black mass samples was fed from the top into the furnace in 60 minutes, together with limestone and sand. The experiment started with a liquid molten bath of 400 kg starting slag, obtained from previous smelting operations, for which the composition is listed in Table 5. The temperature of the liquid bath was maintained at approximately 1500°C.

[0129] The feed for the experiments is shown in Table 5.

[0130] Table 2: Starting slag in the furnace, and feed added to the furnace for the example of packaging. Input Mas Al Si Ca Mn Co Cu Ni Li S (wt%.) (wt.%) (wt%.) (wt.%) (wt° / o.) (wt.%) (wt%.) (wt.%) (kg)

[0131] Starting 400 27.3 5.8 15.5 4.8 1.0 0.5 0.2 2.7 slag

[0132] BM type 1 100 3.2 - - 9.1 13.8 2.2 13.5 4.4 Limestone 4 - 0.7 38.0 - Sand 5 - 46.8 - - -

[0133]

[0134] The distribution ratio for the metals in the alloy phase versus the slag phase was 94:6 for Ni, 81 :19 for Co, and 89:11 for Cu. The other elements, including Al, Si, Ca, Mn and Li were hardly present in the alloy phase.

[0135] It is demonstrated that the applied pO of 10 ® ® is sufficiently reducing and allows for the successful separation of Ni, Co and Cu from Li, Mn and Al.

[0136] DustTrak™ DRX Aerosol Monitor 8534, a dust measuring device, was installed at the feeding port of the furnace to monitor dust emissions at the top of the furnace, above the liquid bath. The measured total dust concentration for BM type 1 conditioned by packaging in Al bags was 0.498 mg / n In contrast, the measured average total dust concentration was 1 .99 mg / m^ for loose black mass feeding.

[0137] As an alternative to a direct measurement of the dust concentration above the liquid bath, the furnace was equipped with a sensor capable of monitoring bath height over time using radar technology. Pyrometallurgical processes exhibit bath fluctuations due to gas release during smelting feed materials. This characteristic can be used to indirectly estimate dust-to-dust transfer.

[0138] Material packaged in Al bags results in the greatest average increase in bath level over the duration of the feeding (i.e. , 1 .248 mm / g BM). This indicates that on average, a larger portion of the feed reaches the bath, reacts, and contributes to foam formation.

[0139] Black mass packaged in iron cans showed results in almost the same order of magnitude, i.e. an increase of 1.175 mm / g BM.

[0140] There is a notable difference with paper and plastic bags, measuring only an increase of 0.612 mm / g BM and 0.520 mm / g BM respectively. For comparison, feeding the BM type 1 without packaging resulted in an increase of 0.08 mm / g BM. Due to the high melting points of aluminum and iron, the packaging materials endure longer, allowing the BM type 1 to enter the liquid bath and melt. In contrast, plastic and paper packages ignite more readily, potentially already above the liquid bath, thereby less efficiently delivering the black mass powder to the liquid bath. Therefore, aluminum is the preferred packing material to bring black mass to react with the slag bath.

Claims

CLAIMS1. A process for recovering Ni and / or Co from black mass, further containing Li, the process comprising the steps of:- conditioning the black mass;- feeding the black mass into a furnace;- smelting the black mass under reducing conditions, thereby forming a liquid bath with an alloy phase containing more than 80% of at least one of Ni or Co, and a Li-containing slag phase; and,- separating the alloy phase and the slag phase;wherein a total dust concentration above the liquid bath is 1 .5 mg / m3 or less; and,wherein the conditioning of the black mass comprises packaging.

2. Process according to claim 1 , wherein an 02-bearing gas is introduced into the liquid bath by submerged injection.

3. Process according to claim 1 or 2, wherein the black mass has a carbon content of 0 to 50 wt%.

4. Process according to any one of claims 1 to 3, wherein the smelting under reducing conditions is performed at a pO2 of 10'7to 10‘1 1.

5. Process according to any one of claims 1 to 4, wherein the slag phase has a Ca / AI ratio of 3.2 or less.

6. Process according to any one of claims 1 to 5, wherein the slag phase has a SiO2 / (CaO+ AI2O3 + SiC>2) ratio of 0.4 or less.

7. Process according to any one of claims 1 to 6, wherein the black mass before the step of conditioning has a moisture content of 0 to 30 wt% or 5 to 25 wt% or 5 to 15 wt% or 15 to 25 wt%.

8. Process according to any one of claims 1 to 7, wherein a dust-to-dust transfer of Ni and / or Co from feed material to the off-take zone or gas cleaning system of the furnace is less than 20%, preferably less than 10%.

9. Process according to any one of claims 1 to 8, wherein the conditioning is packaging, and wherein the packaging comprises the steps of:- providing a bag made of a material comprising a metallic material, paper or plastic;- filling the bag with black mass; and,- subsequently sealing the bag.

10. Process according to claim 9, wherein the metallic material is aluminium.

11. Process according to claim 9 or 10, further comprising a step of removing air from the bag before sealing.

12. Process according to any one of claims 1 to 11 , wherein the feeding is conducted from the top of the furnace.

13. Process according to any one of claims 1 to 12, wherein the smelting under reducing conditions is autogenous.

14. Process according to according to any one of claims 1 to 13, further comprising a step of fuming lithium from the liquid bath.

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