Application of ionic liquid-liquid chromatography (ILLC) to extractions of metals

Lead Research Organisation: Queen's University Belfast
Department Name: Sch of Chemistry and Chemical Eng

Abstract

The separation of and isolation of metals is one of the first areas of human scientific endeavour. With limited resources on earth, particularly of noble metals together with the ever increasing demand for their use, new technologies that allow them to be produced, recycled and reused are urgently needed. Also, lanthanide and actinide elements are being required in ever increasing quantities in the electrical, electronic and nuclear industries. This proposal describes the development of a new general purpose methodology for the separation of metal compounds and salts. This allows metals recovered from waste such as catalytic converters, electronic scrap, or even from metal ores to be separated and isolated in a pure form that can eventually be put back into commercial use.

The metal separations use the new technology of ionic liquid-liquid chromatography (ILLC) which is an advanced form of countercurrent chromatography (CCC), which uses ionic liquids as one of the phases. Ionic liquids (ILs) have unique properties that can overcome the problems associated with the use of conventional organic solvents in separations. They are composed entirely of ions, are liquid at or near room temperature and can dissolve a wide range of organic and inorganic molecules, especially metal salts. Importantly, ILs have no measurable vapour pressure at ambient temperatures and are generally non-flammable. The relatively high costs of ILs have prevented their extensive use in continuous large-scale systems. Intensified technologies (which require less solvent), will allow the benefits of ILs to be exploited. One such intensified technology is counter current chromatography. Because of their high viscosities, the application of ionic liquids in counter current chromatography systems has been very limited and usually in solution in low viscosity solvents, which negates the purpose of the IL. This limitation was solved at QUILL in collaboration with AECS, to produce a unique, ionic liquid-liquid chromatography system (ILLC). In the proposed research project innovative intensified extraction technologies which combine the unique solvent properties of ionic liquids with the high performance of ILLC will be investigated for the separation of metals (noble, lanthanides, uranium).
The research will be carried out by two teams which are QUILL in Northern Ireland and UCL in London. The collaboration will be strengthened by the involvement of AECS, which will design and build the ILLC instruments based on the project needs. ILLC is a new high performance separation technology that will be studied under this joint proposal in two separate ways. QUILL will carry our research into the direct metal separations and their scale up for commercial use, and design and produce ionic liquids necessary for the research proposed. UCL will study the hydrodynamic and mass transfer phenomena in ILLC and develop predictive models of the process that can be used to maximise the performance. High speed imaging and Laser Induced Fluorescence (LIF) studies will help elucidate the flow and mixing regimes in ILLC separations. Factors such as how flow rates, instrument parameters, ionic liquid and solvent properties and choices affect separations and will be investigated.
The results of the QUILL and UCL studies will be combined to generate scale up protocols for metal separations with the ultimate goal of developing separations that are more efficient, have lower energy demand and use safer less noxious solvents that are currently used in the metal separation industry.

Planned Impact

The research will have a direct impact on a number of industries, training of people, and on society, contributing to a safe and secure energy future for the UK.

Industry:
The research will have a significant impact on a number of chemical, nuclear and recycling industries. ILLC is well suited to the recycling of noble metals from recovered catalysts, catalytic converters, and circuit boards (also known as E-waste). The technology is also relevant to spent nuclear fuel reprocessing for reducing the volume and toxicity of the nuclear waste. The following activities will ensure effective communication of the project results to the relevant stakeholders and their engagement for further exploitation of the ILLC technology.
Links with process industries in existing research and industrial consortia: We have substantial links with process industries via QUILL, with an industrial consortium of 12 companies (including Merck, Umicore, and BASF). In addition, the UCL PI is a co-investigator in the multi-institutional EPSRC projects MEMPHIS and PACIFIC (with support from BP, Chevron, P&G, EDF). The consortia will be used as an avenue to disseminate the results of the work, and to engage with industries with potential applications of ILLC. The organisation of a workshop on novel separation technologies for metal reprocessing, targeting both industrialists (electronic, energy and process industries) and academics will be carried out in order to maximise the impact of this work.

Presentations in conferences and publications: The exploitation of the technology and of the results will be handled through QUILL and UCL Business. In QUILL, there is a proven track record in patenting and licensing intellectual property.

Training and Investment in People:
There will be significant training of the researchers recruited in the project in the following areas:
(A) Interdisciplinary research knowledge and skills transfer between chemists and chemical engineers by researchers spending time in their collaborators' laboratories for a few weeks every year.
(B) Industrial practice and issues of technology transfer by the close involvement with both AECS and QUILL member companies who will train researchers in industrial practice and on issues of developing new technologies that can be taken up by industry.
(C) Communication skills and career development through participation in conferences and meetings and writing of research publications and project reports. Both Universities run substantial programmes on career development of researchers.

Society
Current separations of metals and spent nuclear fuel use organic mixtures that have high hazard ratings and low flash points. The unique properties of ionic liquids can overcome many of these problems, while the intensified ILLC will further reduce the amount of extractants and solvents required. ILLC will provide a direct means for separating metals from E-waste and spent catalysts. Their combination will result in a sustainable and environmentally friendly technology. We plan to disseminate the results of the project to the wider public through activities such as:

(A) Articles in general publications: Articles that discuss the importance of intensified separation technologies, of ionic liquids and of their application to treating E-waste and spent nuclear fuel will be posted on the Universities web sites and in publications with wider readership (e.g. New Scientist).
(B) Public and young people engagement activities: In the Departments we run day-courses for school children that promote the role of science and engineering in solving societal problems. In these events we will illustrate the importance of green solvents and of intensified technologies for sustainable energy and process industries and raise awareness on the general issues of E-waste and of nuclear power.

Publications

10 25 50
 
Description The research carried out was to develop and test a series of metal ion separations using Countercurrent Chromatography (CCC) and Centrifugal Partition Chromatography (CPC) with water / ionic liquid solvent systems. These separations are intrinsically clean separations which use water as a mobile or carrier phase and an ionic liquid containing stationary phase. This results in the separations being clean, safe, and produce almost no pollution, and do not consume any chemical reagents. The metal separations that were published, or are in the process of being published, were separations of transition metal salts and rare earth metal salts (or lanthanide metal salts). In addition, the project was to design and develop the CCC and CPC equipment and study the performance and mechanism of these separations.
The achievements made as result of the award were:
(1) Successful separations of transition metal salts such as Copper, Nickel and Cobalt chlorides from each other using water as the mobile carrier phase was investigated and published in two scientific journals.
(2) The conventional production and separations of rare earth metals results in large amounts of acidic waste being produced. The award has led to the invention of an acid free water-based direct separation process for rare earth metals. The clean separations of praseodymium from erbium salts is in the process of being published and research is continuing to give further improvements the process. The CCC instrument is capable of yielding pure rare earth metal salts (dissolved in water) in 15 minutes at very high sample loadings.
(3) The separation equipment was of a new design, which was developed, and tested out under the award, and is now are now being manufactured by a UK SME called AECS Ltd. This has led to exports from the UK to Brazil, Canada, the USA of the CPC instruments designed and developed under the award.
(4) It was discovered that the CCC and CPC instruments could be used for carrying out chemical reactions as well as for performing clean metal separations. The CCC machine was used for making and synthesising the ionic liquids which were tested and used in the metal separation award. These chemical reactions were carried out under computer control, and this has led to the investigation and successful testing of the CCC instrument as a computer controlled automated chemical synthesiser. This new research is currently under active investigation.
Exploitation Route The finding can be taken forward in a number of ways:
(1) The CCC / CPC equipment developed in the award is computer controlled and capable of being fully automated. This allows automated continuous or semi-continuous separations to be carried out. This research could lead to clean automated separations, on the process scale with water / ionic liquid solvent systems. This research is of interest to the bio-pharmaceutical industry and metal refining industries.
(2) The CCC / CPC equipment and ionic liquid solvent systems can be used for a wide range of separations, not just limited to metals. The solvent systems developed under the award can be used for bio-separations and organic chemical separations, which would be of use to the pharmaceutical industry. The exploitation of this research is underway in the medical cannabinoids industry.
(3) The CCC and CPC instruments have been tested and found to function as biphasic flow reactors, where one liquid phase is retained within the CCC / CPC instrument and the other liquid phase can be used to add or remove chemical reactants and remove products of the reactions. This allows CCC and CPC instruments to be used as computer controlled chemical synthesisers. This research is of interest to the pharmaceutical industry.
(4) The research could be used for the recycling of metals from green energy systems and e-waste. Lithium batteries typically contain lithium and cobalt salts and rechargeable NiMH batteries contain nickel and lanthanum salts. This would allow the recycling and recovery of metals from batteries used in, for example, the automotive industry.
Sectors Aerospace

Defence and Marine

Chemicals

Education

Electronics

Energy

Environment

Manufacturing

including Industrial Biotechology

Transport

 
Description New Technology for High-Performance and High-Capacity Bio-separations: Protein Purification using "Hydrophobic Water" Solvent Systems
Amount £149,975 (GBP)
Funding ID BB/R022364/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 08/2018 
End 01/2020
 
Description Development of counter-current chromatography instrumentation for the separation of metals 
Organisation Electrification Construction Services Ltd
Country United Kingdom 
Sector Private 
PI Contribution We have provided data on the operation and performance of countercurrent chromatography instrument to AECS (our instrument manufacturer), for the design of better performing instruments for metal separations. This data has been used to improve on the design of CCC coils and CPC rotors. We have tested out an AECS dual flow rotor and used this information to boost its performance. These improved designs are being used in the nuclear industry.
Collaborator Contribution AECS have produced a modified set of coils and rotors that have the capability of carrying out dual flow separations, which will allow the continuous separation of metals. This has very important commercial significance, since this can be scaled up and allow boost the space time yield of the separation processes.
Impact A nuclear research organisation (details cannot be given due to confidentiality agreements) is investigating dual flow countercurrent chromatographic methodologies using solvents (including ionic liquids) developed as part of this project.
Start Year 2009
 
Title Development of Centrifugal Partition Chromatographic Apparatus for the Production of Medical Cannabinoid Pharmaceutical Products 
Description The collaboration between QUILL Research Centre and the UK SME AECS Ltd. while under EPSRC research funding has led to the design and manufacture of new and improved, centrifugal partition chromatographic (CPC) equipment, manufactured by AECS Ltd, which is generatyed equipment sales and is being used in the medical cannabinoid production industry in Canada and the USA. These CPC instruments are currently being installed and used for the simultaneous separation of up to five separate medical cannabinoids found in hemp plant (Cannabis Sativa). This is currently enabling the medical cannabinoid industry to produce new cannabinoid products for clinical trials and testing, prior to general sales. 
Type Therapeutic Intervention - Drug
Current Stage Of Development Small-scale adoption
Year Development Stage Completed 2019
Development Status Under active development/distribution
Impact The cannabinoid separations industry in the USA and Canada is facing regulatory difficulties as a result of the release of volatile organic solvents used in the production of canabinoids, and from the presence of agricultural chemical residues found at trace levels in cannabinoid medical products. The UK manufactured CPC equipment sold by AECS Ltd. and currently being installed and used in the USA and Canada is being used to remove agricultural chemical residues from medicinal cannabinoid products. In addition, cannabinoid separations which do not require volatile organic solvents are under active investigation by the QUILL Research Centre and AECS Ltd.