Microbial extraction of critical materials from waste feedstocks

Abstract

Disclosed herein are methods for microbial extraction of a material of interest from a solution.

Description

Attorney Docket No. NREL PCT 24-137MICROBIAL EXTRACTION OF CRITICAL MATERIALS FROM WASTE FEEDSTOCKSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. § 119 to U.S. provisional patent application no. 63 / 704,337 filed on 070ct2024, the contents of which are hereby incorporated in their entirety.CONTRACTUAL ORIGIN

[0002] The United States Government has rights in this invention under Contract No. DE- AC36-08GO28308 between the United States Department of Energy and Alliance for Sustainable Energy, LLC, the Manager and Operator of the National Renewable Energy Laboratory.BACKGROUND

[0003] Integrated biohydrometallurgy process could enable low-energy, low-emissions, low- toxicity routes to recover critical materials (CMs) from waste feedstocks. Bioleaching converts solid matrices into solubilized metal ions, which then must be separated / refined in subsequent steps. Bioleaching serves as a complementary strategy to enrich low-grade feeds and is often used in tandem with biosorption or chemical separation. Bioligand-based separations generate pure metal streams from solubilized inputs, such as a bioleachate stream. Preliminary lifecycle assessment indicates bioleaching is cost-effective and can reduce greenhouse gas emissions, energy, and toxicity by greater than 92% each, and separations by simulated moving bedsAttorney Docket No. NREL PCT 24-137 approach could further reduce the environmental impact by an order of magnitude in a low- energy, low-solvent, highly scalable process.

[0004] Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 depicts an overview of the proposed integrated biomining processes.

[0006] FIG. 2 depicts conventional hydrometallurgical process scheme and expected feedstock compositions for leaching, Al / Fe removal step, and Cu removal steps, showing that Li is recovered at the last precipitation step.

[0007] FIG. 3 depicts NMC 622 cathode material leaching efficiency among various biolixiviants at pH 2 and 7.

[0008] FIG. 4 depicts LiCl separation from a mixture of heavy metal ions in chloride salts using QAC3CA column (i.d. 1cm x Lc 27 cm), feed (lOg / L each salt, pH 4-5) loading 20 mL and eluting with water at 2 mL / min.

[0009] FIG. 5 depicts Li2SO4 separation from a mixture of heavy metal ions in sulfate salts using QAC3CA column (i.d. 1cm x Lc 27 cm), feed (lOg / L each salt, pH 3.9) loading 60 mL and eluting with water at 2 mL / min.

[0010] FIG. 6 depicts (A) a scheme of sequential separations of each metal ions using chelating resins, (B) known equilibrium adsorption constants of heavy metal ions, (C) breakthrough curve of citrate salt in step 4, and (D) a photo of the collected citrate effluent (cobalt citrate) and Ni-saturated column after step 4.Attorney Docket No. NREL PCT 24-137

[0011] FIG. 7 depicts (A) development of separation train in LAD system, (B) zone configuration for separating two components in a continuous mode (step time at t4 in (A)), and (C) column configuration for continuous LAD system.DETAILED DESCRIPTION

[0012] Disclosed herein are compositions of matter and methods useful for energy-efficient and low-cost recycling processes for recovery of critical minerals and materials from spent lithium- ion batteries via “next-generation” biohydrometallurgy. Biohydrometallurgy is a broad term for processes which utilize of microorganisms to extract metals in aqueous solutions. In this context, engineered bacteria leach metals from spent lithium-ion battery cathodes / mining wastes into solution with organic acids (termed “bioleaching”) and metals in the leachate are separated into pure streams for re-use in new batteries by ligand-assisted chromatography via simulated moving beds (FIG. 1). An innovation underpinning this technology is the application of synthetic biology to (i) deliver bacterial strains robust enough to tolerate the high concentrations of metals present in lithium-ion battery cathode material waste streams, and (ii) convert waste carbon to chelating agents (termed “biolixiviants”) at high titers that both enables high leaching efficiencies and (iii) use those biolixiviants in chromatographic separations.

[0013] Acidithiobacillus bioleaching strains or transferrable genetic targets.

[0014] Technologies that are under development include:

[0015] Disclosed herein are evolved or engineered strains of Acidithiobacillus ferrooxidans or Acidithiobacillus caldus which have improved microbial tolerance to lithium, nickel, cobalt, manganese, or other black mass components, or mixtures thereof; improved microbial tolerance to rare earth elements, copper, or other metal targets of interest; improved production of targetAttorney Docket No. NREL PCT 24-137 biolixiviants. In an embodiment disclosed herein are methods for the improved leaching of metalcontaining feedstocks including mine wastes, metallurgy wastes, manufacturing wastes, and end- of-life materials including batteries, magnets, and photovoltaics.

[0016] In an embodiment, disclosed herein are genes which contribute to metal tolerance in Acidithiobacillus ferrooxidans or Acidithi abaci llus caldus and engineering of these genes into other microbial chassis.

[0017] Cupriavidus bioleaching strains or transferrable genetic targets.

[0018] In an embodiment, disclosed herein are evolved or engineered strains of Cupriavidus necator or Cupriavidus metallodurans which have; improved microbial tolerance to lithium, nickel, cobalt, manganese, or other black mass components, or mixtures thereof; improved microbial tolerance to rare earth elements, copper, or other metal targets of interest; improved production of target biolixiviants; new genes. Identification of genes which contribute to metal tolerance in Cupriavidus necator or Cupriavidus metallodurans and engineering of these genes into other microbial chassis.

[0019] Optimized microbial consortia for improved bioleaching.

[0020] In another embodiment, disclosed herein are methods and systems for the isolation, characterization, optimization, and / or engineering of microbial consortia to optimally recover target metals from diverse waste feedstocks including mine wastes, metallurgy wastes, manufacturing wastes, and end-of-life materials. In a further embodiment, genetic tool development in naturally occurring microorganisms isolated from consortia is contemplated.

[0021] Novel use or production of organic acid (bio)lixiviants.

[0022] In an embodiment, disclosed herein are technologies that use organic acids as chelating agents for selective leaching of metals, including linear polyamines (e g., spermine andAttorney Docket No. NREL PCT 24-137 spermidine), carboxylic acids (citrate and 2-methylcitrate, 5 -ketogluconate, 2-pyrone-4,6- di carb oxy late), pyridine derivatives (dipicolinate, bis-2-picolylamine), and organosulfur compounds (cysteine, cystine, dihydrolipoate, and glutathione) which are derived from engineering microbial production of these molecules, including from waste carbon.

[0023] Novel metal -binding metabolites and proteins

[0024] Disclosed herein are methods for the the discovery of genes, proteins, or metabolites that bind target metals through genetic, transcriptomic, metabolomic, and proteomic approaches to discovery including from AcidithiobciHus, Pseudomonas, and Methanotrophs. In an embodiment, the use of these molecules in methods disclosed herein will improve leaching or separations of target metals.

[0025] Organic acid-based bioleaching paired with ligand-assisted displacement chromatography

[0026] In an embodiment, methods disclosed herein result in an energy-efficient and low-cost recycling process for recovery of critical minerals and materials from spent lithium-ion batteries via “next-generation” biohydrometallurgy. Biohydrometallurgy is a broad term for processes which utilize of microorganisms to extract metals in aqueous solutions. In this context, engineered bacteria leach metals from spent lithium-ion battery cathodes / mining wastes into solution with organic acids (termed “bioleaching”) and metals in the leachate are separated into pure streams for re-use in new batteries by ligand-assisted chromatography via simulated moving beds (FIG. 1). Methods disclosed herein may be used to apply to fields including synthetic biology to (i) deliver bacterial strains robust enough to tolerate the high concentrations of metals present in lithium-ion battery cathode material waste streams, and (ii) convert waste carbon to chelating agents (termedAttorney Docket No. NREL PCT 24-137“biolixiviants”) at high titers that both enables high leaching efficiencies and (iii) use those biolixiviants in chromatographic separations.

[0027] In an embodiment, the upstream process is a bioleaching process that dissolves metals from solid wastes / ores into acid media using biolixiviants produced from engineered bacteria. We are currently developing several ‘novel’ manifestations of this process, including: Acidithiobacillus ferrooxidans based bioleaching systems which have improved tolerance to lithium, cobalt, nickel, and manganese metals ions and leach metals via microbially-produced sulfuric acid; and Cupriavidus necator based bioleaching systems which have improved tolerance to lithium, cobalt, nickel, and manganese metals ions and leach metals via microbially-produced organic biolixiviants. In an embodiment, 2-pyrone-4,6-dicarboxylic acid is used to chelate / leach metals and enable downstream separations.

[0028] In an embodiment, the downstream processes include an upfront filtration followed by a chromatographic purification process known as ligand-assisted chromatography (LAC). In LAC, the metal ions extracted by biolixiviants will be separated based on different retention time, determined by a ligand-to-sorbent affinity of each element. In an embodiment, the biolixiviant agents will be directly used as a chelating agent or ligand in the mobile phase of chromatographic separations to reduce chemical consumption and footprints. In an embodiment, LAC is operated in a continuous mode by adapting a Simulated Moving Beds (SMB) approach.

[0029] In the SMB approach, commercially available cation exchange resins, anion exchange resins, chelating type resins, and amphoteric (zwitterionic) resins can be employed to realize high selectivity (i.e. ligand-sorbent affinity differences) between target mineral ions. Furthermore, bioderived functional groups can be employed either in ligands or stationary phase to increase theAttorney Docket No. NREL PCT 24-137 selectivities among target minerals. For instance, the peptide-binded resins can be developed and used for metal purification to increase the selectivity between metal ions.

[0030] The primary challenges with CM recovery from waste feedstocks are (i) chemical- and emissions-intensive leaching, (ii) environmentally damaging separations, and (iii) challenging economics for large-volume low-CM-concentration recovery. Existing pyro- and hydro- metallurgical CM recovery strategies have significant drawbacks, including intrinsically high greenhouse gas (GHG) emissions (e.g., smelting) and large chemical footprints (e.g., concentrated acid and oxidizer used in leaching, solvent concentrated acid usage in conventional separations). However, there is a strong incentive to develop sustainable approaches to CM recovery as a range of diverse waste feedstocks are available domestically, including: spent batteries (Li-ion, LIB), magnet scrap / swarf, electronic waste (e-wastes; HDD, phone), fly ash, low grade CM ore, mine tailings, low grade CM brines, phosphogypsum, small motors, spent catalysts, biomass (e.g., metal ion-bioaccumulating plants, seaweed / algae), municipal solid waste, and wastewaters. Many of these feedstocks contain a complex mixture of organics and multiple CMs, presenting both leaching and separations challenges. Bioprocessing is an emerging alternative for CM extraction and separation which leverages inherent technical and environmental advantages.

[0031] Bioleaching in hydrometallurgy industry

[0032] Bioleaching / biooxidation has been used for recovery of metals by natural or indigenous microbial processes since Roman times and has been commercialized for mining sulfidic ores but remains a niche technology (about 5% of Au, about 20% Cu globally) due to key technological challenges. Chile has led bioleaching efforts, recovering copper oxides by using a sulfuric acid leaching agent that feeds the leachate easily into a solvent extraction-electrowinning (SX-EW) process. In 2010, 42% of Chilean SX-EW processed copper was biologically extracted and theAttorney Docket No. NREL PCT 24-137SX-EW process accounted for 39% of Chilean annual copper production. Others have proposed to deliver tailored biological inocula for improved heap leaching, or use biological dissolution processes for e-wastes.

[0033] Conventional hydrometallurgy: Typically, recovering Li, Co, and Ni ions from other cations in hydrometallurgical is conducted by multiple sequential precipitation processes (FIG. 2), which in turn generates Li ions mixed with base, Ca(OH)2 or NaOH, and their salt forms. Co and Ni separation is a challenging step, which can be performed by liquid-liquid extraction or ion exchange process.

[0034] In an embodiment, integrated biohydrometallurgy process enable low-energy, low- emissions, low-toxicity routes to recover CMs from waste feedstocks. Bioleaching converts solid matrices into solubilized metal ions, which then must be separated / refined in subsequent steps. Bioleaching serves as a complementary strategy to enrich low-grade feeds and is often used in tandem with biosorption or chemical separation. Bioligand-based separations generate pure metal streams from solubilized inputs, such as a bioleachate stream. Preliminary lifecycle assessment indicates bioleaching is cost-effective and can reduce greenhouse gas emissions, energy, and toxicity by greater than 92% each, and separations by simulated moving beds approach could further reduce the environmental impact by an order of magnitude in a low-energy, low-solvent, highly scalable process.

[0035] Bioleaching process development:

[0036] Some lixiviants can be produced biologically such as citric acid, spermidine, dipinolinic acid, and 2-pyrone-4,6-dicarboxylic acid. FIG. 3 depicts a more than five-times increased leaching efficiency among Ni, Mn, Co, and Li of NMC 622 (cathode material) using biolixiviants. As shown in FIG. 3, dipicolinic acid shows the highest leaching efficiency at pH 2,Attorney Docket No. NREL PCT 24-137 compared to control (water and sulfonic acid) and other lixiviants. This indicates a promising bioleaching capability.

[0037] Downstream process development.

[0038] In an embodiment, methods disclosed herein result in Li separation from other heavy metal ions resulting from sulfate leaching.

[0039] Focusing on Li recovery, we developed a zwitterionic chromatography process using only water to fractionate metal cations, resulting in LiCl salt is eluted faster than other heavy metal ions. In this approach, a zwitterionic functional group, quaternary ammonium and carboxylic acid, allowing salt to be partitioned such that Li can be recovered first with high purity in water and then the mixture of heavy metal ions can be further treated to separate from each other.

[0040] In an embodiment, a mixture of equal mass concentration of metal chloride salts are eluted with only water on the column packed with (1) 3-carboxy-N,N,N-trimethylammoium (carboxybetaine) functionalized polymer resins (QAC3CA resins) and (2) sulfobetaine functionalized resins (QAC3SA).

[0041] As depicted in FIG. 4, LiCl elutes faster than other heavy metal ions in a QAC3CA column, yielding a recovery of 88 to 93% with a purity of 93.5 to 98.7% depending on the pH of feed solution, respectively. Due to the long tailing of Ni and Co peaks, we used citric acid (1—10 M) to strip off the remaining Co and Ni (0.5-5%) and regenerate the bed.

[0042] However, when the salts are in a sulfate form, heavy metal ion salts are eluted faster than that of chloride form. Without being limited by theory, it was assumed that a bigger size of sulfate than chloride and divalent charges of anions weaken the interaction between metal ions and the stationary zwitterion thus, sulfate salts generated shorter tailing, compared to a chloride salt form. As a result, the Li sulfate salt peak has a large overlap with other peaks, yielding a lowAttorney Docket No. NREL PCT 24-137 recovery (10%) (see FIG. 5), suggesting a long column length to increase the Li fractionation. No metal ions remained in the bed after eluting with water. Thus, this partial separation can be scaled to Simulated Moving Bed (SMB) to achieve a high yield and high purity separation of Li from mixtures of metals and salts thereof.

[0043] Bioligand-based separation of metal ions from mineral acid leaching solution of NMC battery wastes.

[0044] In battery waste recycling, Ni and Co separation has the most difficult separation and Li is recovered in the last step which makes it difficult to purify Li. In an embodiment, disclosed herein are methods for the sequential chromatographic separations of Li, Mn, Co, and Ni using a chelating column (FIG. 6A).

[0045] Using compositions of matter and methods disclosed herein a column can be packed with resins functionalized with chelating resins such as iminodiacetic acid. In an embodiment, Amberlite IRC748 resins were used to pack a column. The IRC748 is a weak ion exchange resins when it’s pre-saturated with base (NaOH). However, if the resins were prewashed with acid, saturating with H+, metal separation showed an adsorption behavior. Thus, at low pH condition, the equilibrium adsorption constants of Mn, Co, Ni on IRC748 have been known in the literature (see FIG. 6B), suggesting that Li will elute out without adsorption but other divalent cations can be adsorbed. Thus, in step 1 (feed loading) and step 2 (washing), Li can be recovered with water. Next, a weakly adsorbed Mn can be eluted out with low concentration of mineral acid (HC1 or sulfonic acid) at pH 3. A column length and elution time need to be optimized to achieve high yield of Mn and leave Co and Ni on the bed. In step 4, Ni and Co are easily separated by eluting with citrate salt. As a demonstration of the step 4, a IRC748 column was preloaded with equimolar (0.1 M) concentration ofNi and Co and 0.2 M sodium citrate (pH 9.0) was loaded on the IRC748Attorney Docket No. NREL PCT 24-137 column. A breakthrough of citrate effluent was observed (see FIG. 6C) and the citrate effluent color became clear when Co was fully stripped off. The color of Ni remained on the bed was green (see FIG. 6D). The purity of Co eluent was 85% suggesting that adjusting pH and ligand concentration is necessary. A dynamic separation mechanism, a competition between adsorption and chelating reactions of Co and Ni with citrate in the mobile phase, results in a clear separation between two ions due to their ligand affinity difference.

[0046] Continuous LAC to purify heavy metal ions (e.g. rare earth elements (REE)) - using biolixiviant leaching methods.

[0047] When critical minerals are leached out by biolixiviant, a chelation chemistry can also be utilized into separation and purification via ligand-assisted chromatography. Disclosed herein are methods for a continuous ligand-assisted displacement (LAD) for downstream process. The principle of LAD is to separate a mixture of cations (e.g. REE) by different ligand selectivity under the cation exchange (CEX) bed. Here, REE is first captured on the bed by displacing a presaturant ion, having the highest ligand affinity. With a continuous ligand elution, fast ion exchange (IX) between ligand chelation and CEX occurs, separating REE species. After moving down the minimum required column length, the IX reaction reaches a dynamic steady state, generating a separated individual REE band as a train, called isotachic train (see FIG. 7A). The elution order is determined by the effective ligand affinity, a ratio of ligand-to-sorbent selectivity. Unlike LLE, LAD shows a high ligand binding efficiency and fast kinetics. Without being bound by theory it is estimated that the LAD process is feasible with anion exchange (AEX) and novel zwitterionic resins such as QA3CA and QAC3SA. However, because the separation train always shows mixed band regions due to mass transfer resistance, the loss of yield or purity from the mixed band regions is unavoidable in batch operation. While batch LAD requires a long column length to reach for aAttorney Docket No. NREL PCT 24-137 full separation, the proposed continuous LAD technology intentionally keeps a partial separation between REE at an intermediate transient state (FIGs. 7B-C). Under a continuous sensor-driven operation, only the purified REE fractions at the end of both bands are recovered periodically. With this approach, we expect higher throughput and yield of greater than 99% purity by using less chemicals for column regeneration than those of batch LAD. Additionally, ammonium sulfates are generated from the column regeneration as a byproduct, which can be directly used for fertilizers. The process design requires rigorous AI / ML driven modeling and simulations for process optimization. Thus, a smart manufacturing approach using in-line UV / vis sensor-driven process data gathering (feedback loop) and Al driven optimization can accelerate process design and enable continuous and autonomous operation (see FIG. 7).

[0048] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting.

Claims

Attorney Docket No. NREL PCT 24-137CLAIMSWe claim:

1. A method for the purification of a metal of interest comprising contacting a solid, solution or colloid comprising the metal of interest with a solution comprising an engineered microbe that comprises a biolixiviant; and wherein the method further comprises adding a solution comprising the biolixiviant to a functionalized zwitterionic resin and then eluting the resin to isolate the metal of interest bound.

2. The method of claim 1 wherein the functionalized resin comprises a zwitterionic resin.

3. The method of claim 2 wherein the zwitterionic resin comprises 3-carboxy-N,N,N- trimethylammoium (QA3CA).

4. The method of claim 2 wherein the zwitterionic resin comprises sulfobetaine (QAC3SA).

5. The method of claim 1 wherein the metal of interest is selected from the group consisting of Ni, Mn, Co, and Li.

6. The method of claim 5 wherein the metal of interest is Li.

7. The method of claim 6 wherein the purified metal of interest is greater than 93% weight by weight pure.

8. The method of claim 6 wherein the purified metal of interest is greater than 98% weight by weight pure.

9. The method of claim 6 wherein the pH of the eluting solution is about a pH of 4.

10. The method of claim 6 wherein the pH of the eluting solution is about a pH of 5.

11. The method of claim 6 wherein the eluent is water.

12. The method of claim 6 wherein the resin is eluted using simulated bed chromatography.Attorney Docket No. NREL PCT 24-13713. The method of claim 6 wherein the biolixiviant comprises at least one functional group selected from the group consisting of organic acid is chelating agent of metals; chelating polyamines, spermine, spermidine, carboxylic acids, citrate and 2-methylcitrate, 5- ketogluconate, 2-pyrone-4,6-dicarboxylate, pyridine derivatives, dipicolinate, bis-2- picolylamine, and organosulfur compounds including cysteine, cystine, dihydrolipoate, and glutathione.

14. The method of claim 5 wherein resin is eluted with 1 M to 10 M citric acid.

15. The method of claim 14 wherein the metal of interest is Mn, Co or Ni.

16. The method of claim 1 wherein the biolixiviant is made by an engineered microbe.

17. The method of claim 13 wherein the engineered microbe is Acidithi abaci llus ferrooxidan or Cupriavidus necator.

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