Bringing processing innovation to the critical-metals supply chain

Rare-Earth Separation

Rare-Earth Separation

Introduction

In recent years there has been a significant effort to find and to develop potential new sources of rare-earth elements (REEs) outside of China. While numerous such sources have now been discovered and are under development, there is very little capacity outside of China for the subsequent processing and separation of the REEs, once they have been removed from the ground.

IMC recognized that this lack of separation capacity was a key bottleneck to the development of a REE supply chain. The company initiated research at a prestigious Chinese REE research institute, which demonstrated that multiple rare-earth concentrates, produced from various REE-bearing mineral sources, could be processed together effectively, resulting in attractive recovery rates. Simultaneously, IMC worked with process-flow-sheet developers from the REE industry in China as well as engineers in Canada, to understand what would be required to establish an independent REE solvent-extraction (SX) facility in North America, for the processing of a range of REE-concentrate feedstocks.

Initial Lab-Scale REE SX Pilot Plant

In 2014, IMC joined a $1.2M REE supply-chain development program, which was led by Technology Metals Research, LLC (TMR) and funded by the US Army Research Laboratory (ARL), part of the US Department of Defense. The Principal Investigator of the program was Gareth Hatch, President of IMC and co-founder of TMR.

The program enabled IMC to construct and to operate a lab-scale pilot plant, with 130 mixer-settler units for conventional SX of REEs, focused on the much sought-after heavy REEs. hosted at the facilities of Process Research Ortech Inc. (PRO) in Mississauga, Ontario. The pilot plant was also used to validate computer modeling tools for the simulation of REE SX circuits.

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Some of the 130 mixer-settler units in the lab-scale conventional SX pilot plant

IMC and PRO tested the process flow diagrams produced by its consultants, successfully running the sequence of SX circuits required to produce separated heavy REE compounds, with purities of 99-99.99%+ total REE purities.

Development of the RapidSX™ Process

In 2015, IMC began work to improve the conventional SX process, through its participation in a $1.7M second phase of the ARL-funded development program. The company evaluated a number of avenues before focusing on a column-based approach, dubbed the RapidSX™ process.

Starting initially at the bench scale, the RapidSX approach was benchmarked against the conventional SX process previously tested by IMC and PRO. With similar flow rates, the system saw a reduction in the number of required processing steps by over 85% and a reduced time to equilibrium by over 85%. The system was used to successfully produce key REEs from both Chinese and non-Chinese-originated concentrates, with commercial-grade purities.

In early 2016 work began on a 10-column pilot-scale RapidSX system, capable of producing up to 2 tonnes of REEs / month. The system was used to separate REEs from non-Chinese concentrates, with purities obtained of 99.5-99.97% total REEs. At the same time, the process of patenting the RapidSX approach was initiated.

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IMC’s pilot-scale RapidSX™ system.

Work was also initiated to test the RapidSX process on concentrates of nickel and cobalt produced from lateritic ores, again with great success.

Commercial-Scale RapidSX REE Separation Demonstration Facility

Following the initial success of the scaled RapidSX-based system, IMC is now in the process of completing its REE-separation pilot-scale work, and developing plans for a commercial-scale demonstration facility, for the cost-effective production of a range of separated REEs via the RapidSX process.

Based in North America and capable of producing up to 2,500 tonnes / year of separated REEs, IMC estimates that this facility would cost in the region of $10-15M to build – a fraction of the cost that a conventional SX facility would require. REEs would be produced in the demonstration facility on a purchased-concentrate or toll-treatment basis.

Partnering with IMC

The company continues to work with future REE producers on the development of the RapidSX program, and seeks additional strategic and financial partners to help make the demonstration facility a reality.

Given the anticipated small plant footprint and low capital costs, IMC is also in discussions with a number of future REE producers, on the potential for placing RapidSX-based separation facilities on the same site as their proposed upstream hydrometallurgical plants. This will allow future producers to cost effectively integrate the processes for the production and separation of REE concentrates, improving the overall margins associated with the production of commercial-grade REE products and compounds.