REG - Rainbow Rare Earths - CIX Test Work shows Very High Purity Separation

Rainbow Rare EarthsAnnouncement

Mon 07:00

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RNS Number : 3726X  Rainbow Rare Earths Limited  01 September 2025

 

1 September 2025

Rainbow Rare Earths Limited

("Rainbow" or "the Company")

LSE: RBW

 

 CIX Test work in South Africa achieves Very High Purity Separation Feed

 

·    Rainbow's low-cost process, optimised at its in-house laboratory in
Johannesburg, has delivered an exceptionally pure mixed rare earth product
utilising continuous ion exchange ("CIX")

·    This purified product delivers a mixed rare earth carbonate
(''MREC'') averaging >55% total rare earth oxides ("TREO") across multiple
test samples / campaigns, considerably exceeding the rare earth industry's
typical refinery specification of >42% TREO

·    The purified mixed REE product compares with the highest grade MREC
specifications produced by any REE development/producing project globally

·    This purification is a major step towards separation success as the
delivery of a high grade; low impurity feed stream is key to achieving
separated rare earth oxides ("REO") of the desired purity

·    The TREO purity of the Rainbow MREC specification after multiple
tests is now consistently >93% vs the accepted industry specifications of
>90%

·    Modelling, and an updated costing, of the proposed final separation
process has now commenced based on this high purity feedstock, significantly
advancing the Phalaborwa project

·    Work on the Definitive Feasibility Study ("DFS") for the primary
leach flowsheet, which is the process that delivers the MREC and which
represents ca. 85-90% of the total project Capex, is progressing well

·    The recent trade-off studies are being incorporated in the DFS and
are expected to deliver further savings in both capital and operating
expenditure

·    As a low-cost, near-term and responsible source of both light and
heavy REE, Phalaborwa can play an important role in the delivery of an
independent supply chain for these critical minerals, which are vital to both
national security and economic resilience

 

NEWS ANNOUNCEMENT

Rainbow Rare Earths is pleased to announce successful results from the ongoing
test work for the Phalaborwa project in South Africa. This unique project
encompasses the recovery and separation of REE from phosphogypsum stacks, a
waste product from phosphoric acid production, meaning that many of the costs,
risks and long timescales associated with traditional mining projects are
eliminated.

 

Considerable progress has been made upgrading the MREC to >55% TREO and
reducing the pregnant leach solution ("PLS") from 340 m(3)/hour down to
between 7-10 m(3)/hour feeding the final separation circuit. Rainbow expects
to finalise the final stages of the process flowsheet to achieve the 99.5%
purity levels in our targeted REE products in the near future.

 

George Bennett, CEO, commented: "These results represent significant progress
for the Phalaborwa project, confirming the potential to become a very low-cost
producer of light and heavy REE, and one of the highest margin projects in
development globally. They also validate our decision to finalise our
flowsheet test work in-house and demonstrate that we have developed the
expertise to address REE extraction and separation in a highly efficient
manner.

 

The West is finally recognising the importance of REE, used in permanent
magnets vital to the functionality of many of the products that underpin
21(st) Century society, as well as to emerging and advanced technologies. A
number of recent initiatives by the U.S., Australian and European Governments
are aimed at improving the economics of, and supporting the financing for, REE
projects to rapidly build out end-to-end rare earth permanent magnet ("REPM")
supply chains.

 

The recent offtake agreement between the US Department of Defense and MP
Materials utilising a floor price of US$110/kg NdPr demonstrated industry
acceptance of a floor price significantly above current market pricing
required to ensure new sources of supply to feed a Westen supply chain. Whilst
Rainbow's project is very robust at current REE pricing and is expected to
deliver a very positive EBITDA. We are therefore very comfortable with this
bench-mark floor price set by MP Materials as it is the same price used for
NdPr in Rainbow's updated December 2024 interim economic assessment of
Phalaborwa which demonstrated the project would generate ca. US$181 million
annual EBITDA once in production."

 

Test Work Update

As set out in the Phalaborwa Laboratory Update announcement in June 2025, key
components of Rainbow's test work at its in-house laboratory in Johannesburg
have been to maximise and maintain overall REE recovery at ca. 65%, and
achieve impurity rejection via CIX. Delivering a high grade, low impurity feed
stream to our final separation process has been highlighted as key to reaching
separated rare earth oxides of the desired purity level, and this has been
successfully achieved.

 

Rainbow is delighted to report the successful culmination of this key
workstream, with the MREC produced by the primary leach flowsheet upgraded
from ca. 44% TREO (achieved in the original piloting process) to the
exceptionally high grade MREC equivalent product announced today of >55%
TREO, which is significantly higher than the industry standard MREC
specification for delivery to Chinese refineries and compares with the top
MREC specifications produced by any REE development/producing project
globally.

 MREC                                                           % TREO
 Rainbow MREC produced in initial piloting work in 2023 / 2024  >44%
 Chinese Specification MREC                                     >42%
 Rainbow mixed REE product produced in July / August 2025       >55%

 

 

Rainbow's in-house team has developed a purification process combining CIX and
precipitation steps, which is a novel combination in REE recovery,
demonstrating the unique intellectual property in REE extraction that has been
built up by the Company.

 

The incorporation of CIX has led to a highly efficient process, with the
ability to reduce the pregnant leach solution ("PLS") flows from 340 m(3)/hr
feeding the CIX down to +/- 7 -10 m(3)/hr feeding the final separation
circuit. This small flow and a simplified final separation process with only
two products is expected to result in modest Capex and Opex for this part of
the circuit.

 

The recovery of REE from the phosphogypsum feed to the mixed REE product has
been ca. 65%, in line with recoveries used in the recent interim economic
study.

 

These results have been confirmed further through extensive large-scale
"lock-cycle" testing (i.e. a repetitive batch test with solution recycle) used
to simulate a continuous circuit, and Rainbow has therefore been able to
confirm the design parameters for the commercial scale CIX forming part of the
project DFS.  The process that has been developed utilises standard CIX and
impurity rejection techniques, used extensively in industry, in an innovative
combination thereby providing scalability for Phalaborwa's flowsheet.

 

Rare Earth Oxide Separation Update

Rainbow's focus is now on finalising the final separation process producing a
high purity neodymium and praseodymium ("NdPr") oxide.

 

In consultation with the industry, the optimal heavy REE product has been
established as a SEG+ which will be a mix of medium and heavy REEs including
the very high value dysprosium ("Dy") and terbium ("Tb") that forms part of
Rainbow's REE basket.

 

Modelling and costing for the proposed separation process has now commenced
based on the successful delivery of the high purity feed noted above.

 

Incoming off-take enquiries have increased considerably following the Chinese
export controls announced, in April 2025, on certain medium and heavy rare
earths and the magnets that contain them. These restrictions have caused major
disruption to the supply chains for high-performance rare earth permanent
magnets, with sectors such as automobile, defense and robotics hit
particularly hard. Rainbow continues to progress discussions with interested
parties and its profile as a low-cost and near-term producer of both light and
heavy REE positions it favorably within the peer group of REE development
companies.

 

Trade-off Studies and DFS Update

A further important work stream for the Company is the trade-off studies to
optimise the primary leach circuit, which represents ca. 85% - 90% of the
Phalaborwa flowsheet and cost base. These studies are progressing positively
and are expected to deliver meaningful savings in power, reagent, labour and
capital costs.

 

The Company intends to use the results of the trade-off studies to provide the
market with an update as to the potential impact on capital and operating
costs for the project ahead of the DFS publication. Rainbow looks forward to
announcing progress on the various stages of the ongoing test work in due
course.

 

The Rainbow Rare Earths Curation Connect showcase can be found here: Curation
Connect - Rainbow Rare Earths Showcase
(https://app.curationconnect.com/company/Rainbow-Rare-Earths-90903?utm_source=media&utm_campaign=media&utm_id=media)
or https://app.curationconnect.com/company/Rainbow-Rare-Earths-90903
(https://app.curationconnect.com/company/Rainbow-Rare-Earths-90903)

 

 

 

For further information, please contact:

 

 Rainbow Rare Earths Ltd   Company  George Bennett         +27 (0) 82 652 8526

                                    Pete Gardner
                           IR       Cathy Malins           +44 (0) 7876 796 629

                                                           cathym@rainbowrareearths.com (mailto:cathym@rainbowrareearths.com)
 Tavistock Communications  PR/IR    Charles Vivian         +44 (0) 20 7920 3150

                                    Tara Vivian-Neal       rainbowrareearths@tavistock.co.uk (mailto:rainbowrareearths@tavistock.co.uk)
 Berenberg                 Broker   Matthew Armitt         +44 (0) 20 3207 7800

                                    Jennifer Lee

 Stifel                    Broker   Ashton Clanfield       +44 (0) 20 7710 7600

                                    Varun Talwar

 

 

Notes to Editors:

 

About Rainbow:

Rainbow Rare Earths aims to be a forerunner in the establishment of an
independent and ethical supply chain of the rare earth elements that are
driving the green energy transition. It is doing this successfully via
pioneering the first commercial recovery of rare earth elements from
phosphogypsum that occurs as the by-product of phosphoric acid production.
These projects eliminate the cost and risk of typical rare earth projects,
which involve mining and the production of a rare earth concentrate that must
be chemically cracked to form a mixed rare earth carbonate before further
downstream processing. As such, Rainbow's projects can be brought into
production quicker and at a lower cost than traditional hard rock mining
projects.

The Company is focused on the development of the Phalaborwa Project in South
Africa and the earlier stage Uberaba Project in Brazil. Rainbow's process will
deliver separated rare earth oxides through a single hydrometallurgical plant
on site, with a focus on the recovery of neodymium, praseodymium, dysprosium
and terbium. These are critical components of the high-performance permanent
magnets used in electric vehicles, wind turbines, defence and exciting new
markets such as robotics and advanced air mobility.

The Phalaborwa updated interim economic study released in December 2024 has
confirmed strong base line economics for the project, which has a base case
NPV(10) of US$611 million. Given Phalaborwa is a chemical processing
operation, with its resource sitting at surface in a chemically cracked form,
it has a much lower operating cost than traditional rare earth mining
projects, and it is therefore estimated to be the highest margin rare earth
project in development today outside of China.

More information is available at www.rainbowrareearths.com
(http://www.rainbowrareearths.com/) and www.curationconnect.com
(http://www.curationconnect.com)

 

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