The future of rare earth processing

The future of rare earth processing:-

The unit was capable of accepting Pregnant Leach Solution and bulk concentrates from REE feedstock locations around the world. To this end Ucore entered into agreements with several REE feedstock providers, and secured test material from a variety of locations.

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1 March 2017
The advantage of technology in the rare earth univers
by: CHRISTOPHER ECCLESTONE

In March 2015, Ucore announced that it had reached an exclusive agreement with IBC to license IBC’s MRT technology (SuperLig) within the Rare Earth industry.

MRT is a branch of Supramolecular chemistry, originally pioneered by Charles Pedersen at E.I. DuPont Laboratories in the 1960’s. That original research into the capabilities of MRT for selective binding of metal ions culminated in the awarding of the Nobel Prize for Chemistry jointly to three researchers (Lehn, Pedersen and Cram) in the development of the technology in 1987.

First some definitions may be in order. Elution, in layman’s terms, is the separation of material by washing; the process of pulverizing substances and mixing them with water in order to separate the heavier constituents, which settle out in solution, from the lighter.

Then, Ligands, which are central to the MRT process are best described as ions or neutral molecules that bond to a central metal atom or ion. Ligands act as electron pair donors, and the central atom acts as a electron pair acceptor. Ligands have at least one donor atom with an electron pair used to form covalent bonds with the central atom.

SuperLig is essentially a customized ligand which is tethered to a solid substrate. The tether enables the ligands to act as a filter. SuperLigs trap the target element as the Pregnant Leach Solution (PLS) is flowed through the column. The raffinate exits and the target elements remain tethered to the substrate by the SuperLig. The eluate then releases the target element and leaves the Superlig ready to trap more target elements when another batch of PLS is flowed through the column. The Superligs are very resilient and remain effective through many cycles. With Rare Earths being so challenging to separate, it was rather canny of Ucore to decide to apply this technology to the Lanthanide Series using samples from Ucore’s Bokan Mountain deposit…. and it was a success.

The advantages of MRT are:

• Low capital and operating costs due to high selectivity and rapid rates of reaction
• Flexible and easy operation offered by:
• ability to treat large concentrations ranges of ions in the feed
• efficient loading and elution profiles
• small number of elution bed volumes
• rapid flow rates and cycle times
• longevity and stability of SuperLig
• automated operation
• Environmentally friendly operation resulting from closed-loop systems
• No contamination of processed solutions by ions transferred from SuperLig
• Waste streams treated by MRT systems contain almost none of the contaminants targeted by SuperLig
• The eluant can often be recycled
• High purity, high-concentration eluate can produce value-added products.

Applications – MRT & PGMs
IBC’s MRT-based SuperLig technology is currently already utilized extensively in metals processing, and is now being introduced into the Rare Earth separation field as a means of both selectively extracting the Rare Earths as a group from a mixed polymetallic solution and of selectively isolating and refining individual high-purity Rare Earth elements.

One of the world’s leading PGM producers, Impala Platinum, has long been a card-carrying fan of MRT with its JV with IBC to market PGM applications of MRT dating back to 1994.

Industrial applications for IBC’s SuperLig/MRT platform in the PGM space are well proven with platinum, palladium and rhodium recovery from spent automobile catalytic converters resulting in high-purity products, improved recoveries, reduced processing costs and metal lock-up. The other application has been palladium separation and purification in PGM refineries resulting in reduced processing time and costs, increased palladium separation efficiency and recovery and reduced environmental impact. It has also been applied to rhodium refining by Tanaka in Japan.

PLS & Mixed Concentrate Preparation
The production of a high-purity heavier REE concentrate is the key initial step in the separation of individual high-purity heavier Rare Earth salts. The resultant salts can be utilized to generate output products tailored to customer specifications. Those products include oxides, carbonates, nitrates and other salts of each of the individual Rare Earth elements. A highly purified concentrate of the heavier REEs can be considered an end product to be sold to independent Rare Earth separation facilities, or can be used as input material for an in-house individual rare earth salt separation facility.

The process through which the PLS flows can be seen in the schematic below:

A Rare Earth-enriched raffinate solution is fed through a further SuperLig extraction which is designed to separate the heavier REE’s, as a group. The heavier REE’s are then eluted from the column with a small amount of eluant and easily precipitated from the resulting concentrated solution to form the carbonate salt. Recovery rates for the HREE’s from the Bokan PLS to the salt are in excess of 99%. The remaining raffinate containing the light rare earths, as well as Yttrium, is preserved for further processing. Ucore has been working to develop a high-purity Yttrium salt as an additional output product of the MRT process.

The >99% pure HREE concentrate is a carbonate salt Rare Earth concentrate comprised of heavy rare earths ranging from Samarium (Sm) through Lutetium (Lu). The Rare Earth concentrate is easily convertible to oxide or other salt forms depending upon commercial requirements and contains the following rare earth content:

In the “final wash” so to speak, MRT produces a clean and high-grade heavy REE mixed concentrate, free of radioactive elements and free of commonly produced elements that interfere with traditional Solvent Extraction separation such as Al, Fe, and Fluoride. While the application of MRT to REE may be pioneering, as an industrial process MRT is a known and proven technology.

Pilot Plant
Ucore commissioned the construction of a pilot plant (codenamed “SuperLig-One”) at IBC’s Utah facility (seen below). The purpose of which was to test the use of MRT for the separation of REE’s on a bulk scale. However, it then started testing other potential special metals.

The unit was capable of accepting Pregnant Leach Solution and bulk concentrates from REE feedstock locations around the world. To this end Ucore entered into agreements with several REE feedstock providers, and secured test material from a variety of locations.

The pilot plant is both modular and portable in design, capable of transport to remote testing sites as required. Columnar units within the Plant contain customized proprietary SuperLig products that are designed to selectively separate the metal being targeted. To optimize utility, the Plant will be customizable over time, with capacity for treating varying ratios of metals in different PLS feed solution​

For more:-
https://investorintel.com/sectors/t...ntel/ucore-mrt-advantage-rare-earth-universe/

Is this the route NTU will eventually take?