Grants and Contracts Details
STATEMENT OF WORK University of Kentucky Investigators: Rick Honaker, PhD, Xinbo Yang, PhD Drs. Honaker and Yang will support Lawrence Livermore National Laboratory on the DARPA EMBER project through modifications of an existing pilot scale plant for REE recovery and purification processing. BASE PERIOD (PHASE I) Technical Area 2: REE Biomining Task 1. Design, develop a modular REE-biomining workflow (m1-19, LLNL, UK, UA, WU, WRE) Subtask 1.1 - RE mineral concentration (UK, Month 0-3) A detailed characterization analysis will be performed at UK on the allanite and monazite feedstock material received from Western Rare Earth. The physical and chemical property of the RE mineral and gangue minerals will be evaluated, and a physical beneficiation process will be developed to produce a concentrate that feeds into the acid baking/cracking process. The mineralogy of the concentrated feedstock material will be analyzed using X-ray diffraction analysis (XRD) to identify sulfide minerals that can assist with microbial activities in bio-leach or bio-mining process. Elemental composition will be analyzed using X-ray fluorescence (XRF) along with Inductively Coupled Plasma Optical Emission Spectrometry and/or Mass Spectrometry (ICP-OES/MS) at the University of Kentucky. Subtask 1.2 - REE extraction from upgraded feedstock (UK, Month 3-12) Detailed experiments will be designed and carried out to investigate the effect of acid concentration, acid dosage, roasting temperature, and roasting time to optimize the REE recovery and selectivity during acid baking process followed by water/acid leach. Thorium rejection during acid baking process will be evaluated for the monazite feedstock. Leaching characteristic of the roasted material will be investigated to maximize the TREE recovery and selectivity. The composition of the pregnant leachate solution (PLS) generated at the optimal acid baking and leaching condition will be evaluated to provide the composition of simulated solution feeding into subsequent biomining process. Subtask 1.3 - Solution stability and speciation study (UK, Month 3-12) The composition of the PLS will be employed to direct a solution chemistry study through thermodynamic calculation. The precipitation behavior of REEs and major contaminant ions will be evaluated with specific objectives of 1) Fe removal, and 2) REE phosphate precipitation. The effect of element concentration, ionic concentration, redox potential will be investigated through theoretical calculation. The simulated precipitation behavior will be verified and validated with 1 the results obtained from the laboratory precipitation experiments using the PLS. Pourbaix diagram will be generated for Fe based on the composition of the PLS. M1: Characterization of components of REE source material M2: Design of biomining concept with preliminary format of individual steps M3: Design of biomining concept with individual steps integrated qualitatively OPTION PERIOD (PHASE II) Technical Area 2: REE Biomining Task 3. Design, develop a modular REE-biomining workflow (m19-36, LLNL, UK, UA, WU, WRE) Subtask 3.1- Feedstock acquisition and preparation (UK, Month 19-22) This task includes all work elements associated with the bulk material collection, pre- concentration and characterization of the upgraded feedstock material provided by Western Rare Earth containing 1000-5000 ppm of total rare earth elements (dry whole-sample basis). The feedstock material will be placed into 55 gallon drums lined with sealed bags and transported to the pilot-scale test facility. All pertinent geographic/stratigraphic information will be documented including location, site description, etc. Representative sample will be subjected to mineralogy and rare earth element (REE) analyses. Subtask 3.3 – Waste disposal and containment plan (UK, Month 22-36) A physical containment plan for the pilot plant operation will be initiated and implemented in collaboration with specialists within the project team to prevent the release of living organisms. The waste streams including solid waste, liquid waste, chemical waste, biological waste will be identified, and the quantity of each stream will be scaled using the mass balance flowsheet to develop a waste disposal plan. The major solid waste includes the solid residues discharged from leaching process and iron precipitates generated from Fe removal process. Solid waste neutralization will be tested by mixing the two solid stream with the alkali minerals with a given amount of lime to ensure long term immobilization of metal ions. The migration of Th in the circuit including leaching, precipitation and biomining process will be monitored to avoid any accumulation and generation of any potentially hazardous wastes. Subtask 3.4 - Thermodynamic analysis of metal speciation (UK, Month 19-36) Thermodynamic analysis of metal speciation will be continued to support the biological and non-biological process development. The solution stability of each stream in the chemical and biological process will be investigated through thermodynamic calculation and speciation diagram to support development of the overall biomining process. 2 M5: Established process for feedstock transfer and waste disposal (m19, UK) M6: Updated biomining concept with format/matrix for individual steps (m24, UK) M7: Updated biomining concept with quantitative integration of individual steps (m24, UK) Task 4. Develop and demonstrate biomining modules for REE purification (m19-36, LLNL, UK, WRE) Subtask 4.1 - Flowsheet integration and process simulation (UK, Month 19-36) A flowsheet will be developed based on finding obtained from TA1 and TA2 efforts. The flowsheet will be integrated with chemical module process and biomining module processes. Based on the single stage separation efficiency and recovery of REEs achieved in TA1, a mass and flow balance flowsheet will be developed using METSIM. REE separation and recovery efficiency for multiple stages will be modeled to compose a biomining module to achieve the required separation efficiency and purity level. Based on the single stage separation efficiency and recovery of REEs achieved in TA1, a mass and flow balance flowsheet will be developed using METSIM. REE separation and recovery efficiency for multiple stages will be modeled to compose a biomining module to achieve the required separation efficiency and purity level. Necessary recirculation configuration will be simulated and evaluated to obtain data for LanM column configuration and plant layout for the REE separation and purification circuit. Subtask 4.2 – Small biomining modular system testing (UK, Month 25-36) Small modular systems of the acid baking, leaching, Fe precipitation, and bio separation components will be constructed and utilized to evaluate and optimize parameter effects on performance. Four of the lab scale LanM columns will be procured and installed in a continuous operation manner to test the first tier TREE biomining circuit with a goal of producing 2 grams of TREE per day with 80% recovery. Several liters of solution will be produced from the column tests for other teams to be used for REE purification and individual element separation tests. The lab scale LanM column continuous test result will support the engineering design of the column operation in the pilot plant in Phase III. The solution obtained from the LanM columns will be used for lab testing for REE separation and purification biomining process development to achieve the goal of recovering 8 individual REEs at 14 g/week TREE, with 80% efficiency from biomass and 90% product purify for each REE. Subtask 4.3 – Process engineering design (UK, Month 25-36) The results from these tests will be used to scale the individual processes and develop a process flowsheet including P&ID drawings with the goal of a system that is capable of producing more than 700 grams per week of REEs as a result of recovering 95% of the REEs from the given feed source. A floor plan will be developed based on the LanM column configuration and footprint. A piping and instrumentation diagram (P&ID) will be developed which shows the piping and 3 process equipment together with the instrumentation and control devices. Material handling system including pump size, pump type, tubing size will be determined based on the mass and flow balance sheet. Proper valve type and size will be determined based on the material type and chemical. The design will support diverse bioreactors and enable modularity of process conditions. In preparation for testing the scaled process system in Phase 3, some of equipment may require special material and longer lead time, thus will be selected and procured with the required process control systems upon approval from DARPA. M6: Extract 80% of target REE at 2g tREE/day M7. Recovery of 8 individual REEs at 14 g/week tREE, with 80% efficiency from biomass and 90% product purify for each REE OPTION PERIOD (PHASE III) Technical Area 2: REE Biomining Task 5: Demonstrate pilot plant scale operation (37-48M, UK, UA, WRE, LLNL, PSU) Subtask 5.1 – Pilot plant construction and equipment installation (UK, 37-42 Month) The current flowsheet of the pilot plant facility at UK includes physical separation, thermal treatment, bioleaching, acid leaching, solvent extraction, and selective precipitation, etc. The plant has a capability of producing high grade mixed REO and critical materials at a rate of 200 gram/day. The bio-mining process will be integrated into the current process pipeline with a goal of replacing the acid leaching process with selective bioleach process, replacing the selective Fe precipitation process with bio-mediated precipitation process, and adding LanM columns for REEs recovery and separation. Selected equipment with supporting tanks and pumps will be installed into the existing pilot plant with the required process control systems following the floorplan and P&IDs. Subtask 5.2 – Demonstration and optimization of biomining circuit (UK, 37-48 Month) Activities will involve the performance of systematic test programs to prove the capability of meeting the production and REE quality requirements as well as the efficacy of bacteria containment. The results from the test programs will be used to identify optimum process conditions and associated reagent and energy requirements. Assessments will also be conducted to quantify the ability of the bio-immobilization process to maintain the radioactive elements in solid form and minimize environmental impact. The LanM column configuration will be plumbed based on the recirculation configuration obtained from Phase II efforts with flexibility for reconfiguration. At least 8 individual REE will be produced from the biomining circuit with a goal of producing 8 final RE oxide product at 95% efficiency with purity of 95% at 700 g/week. Subtask 5.3 – Waste management plan development (UK, 37-48 Month) 4 All process waste slurries will be filtered using high pressure filter presses which will ensure 100% capture of solids and minimal residual moisture. The filter operates in a sequence of steps which allows dilution water to be filtered through the solids cake to assist in neutralizing the solids. The solid residues and iron precipitates generated from the pilot-plant operation will be mixed with the alkali minerals together with a given amount of lime to ensure long term neutralization of the solid residue. Lime dosage requirements will be recorded for the purpose of projecting full-scale cost requirements. A pH monitoring system will be installed on the wastewater produced from the pilot plant and used to control lime solution addition to neutralize the solution pH value. The amount of lime solution will be recorded to obtain dosage and cost data. In areas where fumes may be generated such as the acid baking process and bioreactors, a gas removal system has been included in the budget and will be used to vent the fumes directly outside the facility. All the contaminants will be finally precipitated out as hydroxides and mixed with the solid residues with lime for neutralization. The Th concentration in the mixed solid samples will be measured periodically by representative sampling. M1: Purification of 95% of 8 REEs at purity of 95% at 30 g/week scale (m42, UK) M2: Purification at 95% efficiency of 8 REEs at purity of 95% at 700 g/week scale (m48, UK) Waste Management Plan An Environmental Monitoring & Waste Management (EMM) Plan will be prepared that details the operational controls and procedures necessary to ensure that there is no contamination to air, land or water as a result of the operation of the proposed biomining process. Items to be monitored will include 1) process flows and mass balances of chemical additives used in the REE recovery process; 2) toxicity reviews of chemicals used in the process; 3) effects of living microorganisms used in the REE recovery process to the environment; 4) development of a Spill Containment and Countermeasures Plan (SPCC); 5) assessment of environmental controls (i.e. process and instrumentation controls) for the elimination of potential pollutants in water, solid and air emissions. The plan will address any anticipated environmental impacts, both real and perceived, such that appropriate controls and mitigation strategies can be effectively implanted by facility personnel. A separate subtask addressing concerns and control strategies associated with radionuclides, such as thorium and uranium, using biomining technology will be undertaken by researchers from LLNL. Information from this work will be used to develop a Radionuclide Control & Mitigation Plan that establishes control protocols in the pilot-scale facility that avoid and/or minimize the generation of any potentially hazardous wastes for each feedstock. 5
|Effective start/end date
|8/31/22 → 4/30/24
- Lawrence Livermore National Laboratory: $331,372.00
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