Patent Application
20240191316
Portable or electric vehicle batteries of Li-ion type comprise valuable elements and it is important that they should be properly recycled: Copper Cu, Aluminium Al (2 metals contained in metallic form), Nickel Ni, Cobalt Co, Manganese Mn and evidently Lithium—the latter in the form of combined oxides.
In most known channels, the recycling of these batteries—whether rejects or waste from new battery production, spent batteries or faulty new batteries—include a shredding step in a shredder which separates Copper and Aluminium (metals) in good proportion and produces a «black mass» grouping together the other metals as well as a high proportion of carbon, in elemental form (C-Fix) or in combined form, in plastics and oils similar to hydrocarbons.
It is specified that the production of new batteries produces waste such as cuttings from anode or cathode rolls, anode and cathode rejects, faulty assemblies of anodes and cathodes called bundles, faulty assemblies of anodes and cathodes placed in pouches without solvent called dry cells and faulty pouches with solvents. As an example, a synopsis is given of the waste resulting from the production of new batteries.
Several solutions are currently proposed and being tested to recover this black mass, most often via hydrometallurgical process—and in several steps.
In this document there is proposed a three-step pyrometallurgical recovery solution:
Electric vehicle batteries are of 2 types:
It is this latter type which currently tends to prevail. The possibility and efficiency of the recycling of Li-ion batteries amount to a major challenge in the development of electric vehicles or of portable applications (cells phones, laptops, electric bikes . . . etc.).
The recycling of Li-ion batteries gives rise to major new changes by the manufacturers of these batteries and many alliances have recently been set up for this purpose.
In the remainder hereof there is proposed a solution that associates shredding with a pyrometallurgical process for the compete recycling of these Li-ion batteries.
The principle and exact composition of these Li-ion batteries is widely described elsewhere, and it is sufficient to recall the scale of these batteries which can weigh from a few grams (button type) up to several hundred kilograms as suggested in
The active core of the battery (cathode/anode/electrolyte) is chiefly composed of oxides and/or phosphates of LiNiO2, LiCoO2, LiMnO2, LiFePO4 type, of graphite and fluoride LiPF6 for the electrolyte, dissolved in an organic solvent.
More specifically, the production of new batteries is accompanied by the production of several levels of waste or rejects, such as cuttings from anode and cathode rolls, anode and cathode rejects, faulty assemblies of anodes and cathodes called bundles, faulty assemblies of anode and cathodes packaged in pouches without solvent called dry cells and faulty pouches with solvents.
For example, Table 2 below gives a synopsis of this waste production during the manufacture of new batteries, at different stages.
The valuable elements tat it is crucial to properly recycle on account of environmental- and energy-related costs are Copper Cu, Aluminium Al (two metals contained in metallic form), Nickel Ni, Cobalt Co, Manganese Mn and evidently Lithium.
The potentially important presence is noted of Phosphorus P, a steel pollutant, and of Fluoride F a source of corrosion of the constituent refractories and steels of the processing plant.
The recycling of large-size Li-ion batteries mostly includes complete shredding (
This shredding and the separation tooling following thereafter allow the efficient separation of the metals contained in metallic form—Al, Cu and Fe (steel). The remainder is shred and/or recovered in the form of a mass of sludge composed of fines measuring less than 2 mm and an organic liquid, the mass being called «black mass».
The objective of complete recycling is to recover all the valuable elements in forms that are usable. This objective can be reached with different types of processes—hydrometallurgical or pyrometallurgical. The entire sector is schematized in
At the current time, it would seem that most companies or groups which have launched into the recycling of Li-ion batteries experiment with or are focusing on a scheme such as illustrated in
An example of an analysis of a black mass is given in Table 3 below.
It is to be noted that:
A comparison will not be made here between the proposed industrial processes, but it can simply be said in this case that hydrometallurgical processes in theory suffer from severe handicaps compared with a pyrometallurgical process:
The above provided that a pyrometallurgical solution is able to reach the objective of extracting all the valuable metals in a form that can be reused.
There is therefore proposed a process for recovering the black mass derived from lithium batteries, the process comprising the addition of iron ore or oxidized or non-oxidized scrap iron to the black mass to obtain a mixture, smelting the mixture under the supply of energy to obtain a carburized metal bath, separating a first slag to obtain a purified metal bath, followed by oxidizing treatment of the purified metal bath and separation of a second slag, to obtain a ferroalloy.
The ferroalloy obtained is high Nickel and Cobalt content, the metals to be recovered for the manufacture of high-strength steels. The first slag is high in lithium in oxide form Li2O, and the second slag is high is manganese and lime when lime is added at the oxidizing step, in particular to extract Phosphorus P from the ferroalloy. It is advantageous to separate the two slags independently of each other to allow separate recovery of the lithium and manganese. They are separated by pour-off after decanting, the first before the oxidizing treatment step, and the second after the oxidizing treatment. The presence of iron ore or scrap iron, which is another source of iron, allows the operation to be conducted at lower temperatures and minimizes loss of nickel and cobalt in the form of oxides. In general, and as is the case in the analysis of black mass given as an example, this mass contains sufficient Carbon to ensure reducing of the oxides and carburizing of the metal obtained, up to 3-4% C in the carburized ferroalloy. If this is not the case, carbon is added in the form of anthracite or a substitution carbon material for smelting of the mixture. This ensures that smelting is definitely carburizing i.e. reducing, so that the reducible metals namely cobalt, iron and nickel, but also copper and manganese are effectively reduced.
Advantageously, agglomeration into pellets or briquettes or by extrusion is carried out before smelting. This allows bulk storage and transport via conveyor to the converter, and avoids airborne losses of material when loading.
Advantageously, smelting is carried out in a rotary converter or a converter equipped with an agitation device This allows the mixture to be homogenized while it is being smelted.
Advantageously the addition of iron ore at about 94% iron oxide Fe2O3 in a proportion of ½ quantity of iron ore per 1 quantity of battery black mass is added to the battery black mass to obtain the mixture to be smelted. Depending on the composition of the black mass, this proportion can be varied to target an amount of iron in the ferroalloy close to 50% by weight.
Advantageously, the black mass is derived from shredded or disassembled lithium batteries.
Advantageously, slaked lime is added as binder to facilitate agglomeration at least of the black mass and iron ore or scrap iron.
Advantageously, quicklime which may or may not be pure is added at the oxidizing treatment.
Advantageously, a continuous production operation is launched during which an addition of carbon is made to one fraction of the metal bath resulting from oxidizing treatment after separation of the second slag, this fraction being used to receive new feeds of black mass and iron ore or scrap iron thereby forming the mixture that is the subject of smelting leading to the obtaining of the carburized metal bath.
The proposed process comprises 3 steps:
The process is schematized in
The principle of the process and the objectives of each step can be summarized as follows:
In practice, the smelting of briquettes of the mixture of black mass+iron ore or source of iron such as scrap iron+Carbon (agglomerated by means of a binder e.g. slaked lime) follows the sequence given below summarized in the simplified process diagram in
In a rotary converter the starting material is a «hot metal heel» having ⅓ capacity of the rotary converter and having the analysis of the targeted ferroalloy FeNiCoC; in an operation of continuous production, this hot heel is derived from part of the preceding load that has been re-carburized by adding carbon and agitating the bath by rotation of the converter.
The briquettes of «black mass+iron ore+binder» are fed continuously with short interruptions to pour off excess slag by overflow, until a quantity of metal is obtained corresponding to the nominal capacity of the converter; smelting is conducted continuously with the supply of energy from the «oxygaz» burner and «post-combustion» (combustion of the CO resulting from reducing reactions by injection of additional oxygen).
After complete casting of the furnace slag, refining of the metal can be initiated (extraction of P and Mn) via the continuous injection of oxygen and lime up until the targeted P content is achieved (in general lower than 0.1% P); the remaining metal FeNiCo is then cast but retaining a hot heel of ⅓ the capacity of the reactor, so that the following sequence can be started.
The proportions and compositions of the fed materials, metal baths, and slags obtained are appended hereto.
The black mass of the composition given in Table 3 is additioned with standard iron ore of 94% iron oxide Fe2O3, in the proportion of 1 t BM+0.5 t Fe ore. The result is the mix having the composition given in Table 4 below.
The smelting step is conducted in the converter with the mass balance given in Table 5a below.
Per 1 t of black mass, smelting yields:
Alternatively, the smelting step is conducted in the converter with the mass balance given in Table Sb below, which indicates an addition of lime CaO and magnesia MgO, to obtain the following ratios of basicity in the slag resulting from the smelting step: single basicity CaO/SiO2˜1.5, and global basicity (CaO+MgO)/(SiO2+Al2O3) of 0.7 to 0.8.
Per 1 tonne of black mass, smelting yields:
The supply of energy for this smelting is provided by combustion of the Carbon (graphite C and hydrocarbons HC), by means of an addition of gaseous oxygen injected via a lance into the metal bath/slag. The amount of injected oxygen is about 260 Nm3/t of black mass (200 to 300 Nm3 per tonne of black mass depending on the exact composition).
The refining step entails extracting the Manganese by injecting oxygen, a metal that is readily oxidizable, at the same time that the Carbon, a large portion of Phosphorus and a portion of Iron are removed. A mass balance of this refining step is given in Table 6a.
At energy level, all these oxidization reactions are largely exothermal and more than cover reactor losses.
Per 1 t of black mass, refining therefore gives:
Alternatively, a mass balance of this refining step is given in Table 6b.
Per 1 tonne of black mass, refining gives:
The 3 products obtained have ensured reuse, of which the applications can be specified as follows:
A black mass free of Phosphorus or with low Phosphorus content is of close typical composition, an example of which is given in Table 7 below.
Here the content of Phosphorus is 10 times less than in the standard black mass.
One application of reuse is evidently the one described for high Phosphorus content, comprising 2 steps (smelting and refining) ultimately leading to a low-Phosphorus FeNiCo alloy that can be used in the preparation of high alloy steels with high contents of Ni and Co.
The mass balances of this industry are grouped together in Tables 8a and 8b below.
However, it appears that the main poisonous element for the recycling of highly valuable metals (Ni and Co), namely Phosphorus, is in this case already quite largely removed at the smelting step at which it is lowered to less than 0.1% P in the FeNiCoMnC ferroalloy.
It is true that the standard analysis of FeNiCo alloys of «Maraging» type comprises low Mn and C contents (often less than 0.2% each). Nonetheless there are possibilities of direct use of the FeNiCoMnC alloys, either by including these at a preliminary production phase (at which Mn and C are removed) or for derivative versions of these types of ferroalloy tolerating higher contents of Mn and C.
Batteries of Li-ion type, as valuable elements it is crucial to properly recycle, comprise Copper Cu, Aluminium Al (2 metals contained in metallic form), Nickel Ni, Cobalt Co, Manganese Mn and evidently Lithium—the latter in the form of combined oxides.
In known recovery channels, the recycling of these batteries—whether concerning production waste, spent batteries or faulty new batteries—includes a size reduction step using a shredder which in good proportions separates Copper and Aluminium (metals), and produces a «black mass» grouping together the other metals as well as a high proportion of carbon in elementary (C-Fix) or combined form, in plastics and oils similar to hydrocarbons.
Several solutions are currently proposed and are being tested to upgrade this black mass, most often via hydrometallurgical route—and in several steps.
In this document there is proposed a 3-step pyrometallurgical solution:
The main supply of energy for carburizing smelting is generally combustion of the Carbon in the black mass via injection of gaseous oxygen into the bath.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2103117 | Mar 2021 | FR | national |
| FR2106738 | Jun 2021 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2022/050565 | 3/25/2022 | WO |
