London-listed Rainbow Rare Earths is advancing its Phalaborwa project in South Africa, a development that aims to recover critical rare earth elements from industrial waste rather than from a newly developed conventional mine.
The project is designed to extract neodymium, praseodymium, dysprosium and terbium from approximately 35 million tonnes of phosphogypsum residue accumulated at a former phosphate-processing complex. By using an existing waste deposit as its feedstock, Phalaborwa offers a different development model from traditional rare earth mining projects, potentially reducing exposure to the costs and geological uncertainties associated with establishing a new open-pit operation. Instead, the project’s success will depend heavily on its ability to consistently recover and separate valuable rare earth elements through an advanced hydrometallurgical processing system.
Phalaborwa Targets Rare Earths from Existing Industrial Waste
The fundamental proposition behind Phalaborwa is relatively straightforward: the rare earth-bearing material has already been mined and processed as part of earlier phosphate operations. The estimated 35 million tonnes of phosphogypsum residue therefore represents an existing secondary resource. Rainbow does not need to undertake the conventional sequence of exploration, mine development, drilling, blasting and ore extraction associated with a greenfield rare earth deposit.
That could offer important advantages in terms of both development time and capital requirements. Eliminating traditional mining risks does not mean eliminating technical challenges. The project must demonstrate that rare earths can be recovered from the residue economically and at industrial scale, while maintaining effective control of impurities and chemical consumption. The critical question is consequently shifting from how much material can be mined to how efficiently valuable elements can be extracted from a complex industrial waste stream.
Hydrometallurgy Is Central to Project Economics
Phalaborwa’s commercial model relies on hydrometallurgical processing rather than conventional mining and mineral concentration. The proposed process will need to handle a technically demanding chemical environment while achieving high recovery rates for the targeted rare earth elements. Maintaining stable operating conditions will be essential because variations in feed composition, reagent consumption or impurity levels could affect both production volumes and operating costs.
The project’s economic performance will therefore depend on several interconnected factors, including rare earth recovery rates, impurity management, separation efficiency, reagent requirements and plant reliability.
This makes the ongoing pilot work particularly important. Rainbow is incorporating results from its pilot plant programme into the project’s definitive feasibility study, with the aim of moving the development from a promising secondary-resource concept toward a technically and financially defined processing operation.
Construction Target Set for 2027
Rainbow is targeting construction from 2027, with first production expected around 2028. The project’s interim economic assessment previously indicated a net present value of approximately US$611 million, highlighting the potential value attributed to the rare earth resource and the proposed processing route.
That valuation, however, remains dependent on further technical and financial validation.
The definitive feasibility study is expected to provide greater clarity on capital requirements, operating costs, production performance and the technical configuration required for commercial-scale operations. The results will also be important for potential lenders and strategic investors assessing whether the project can support long-term debt and equity financing.
US-Backed Financing Could Support Development
Rainbow has outlined a potential financing structure involving up to US$50 million of investment backed by the US Development Finance Corporation through TechMet. The proposed support reflects the wider strategic importance attached to alternative sources of rare earth materials, particularly those needed for high-performance permanent magnets. Rainbow has also previously secured US$8.5 million through a royalty transaction with London-listed Ecora Resources. Under that arrangement, Rainbow transferred a portion of future project revenue in exchange for development funding. The combination of project-level financing and strategic investment could help Rainbow advance Phalaborwa toward the construction stage while reducing the immediate funding burden on the company.
European Supply Chains Add Strategic Importance
Although Phalaborwa is located in South Africa, the project has significant links to European and international critical-mineral supply chains. Rainbow’s London listing provides a direct financial-market connection to the United Kingdom, while potential European customers in the permanent-magnet industry could provide an important downstream market for the project’s products.
South Africa’s broader strategic raw-material relationship with the European Union also strengthens the project’s relevance to European supply-chain diversification.
One of Phalaborwa’s potentially important advantages is its focus on producing separated rare earth oxides rather than an unprocessed concentrate. Producing separated products can provide greater value and potentially establish a more direct connection with downstream manufacturers that require specific rare earth materials. This is increasingly important as Europe seeks to diversify supplies of critical raw materials used in electric vehicles, renewable energy equipment, advanced manufacturing and defence technologies.
Waste-Based Model Reduces Mining Risk but Raises Processing Challenges
Phalaborwa illustrates both the opportunities and limitations of secondary-resource projects. Using an existing industrial waste deposit can remove some of the major uncertainties associated with conventional mining. The material is already above ground, eliminating the need to develop a new mine and reducing exposure to geological exploration risk. But the absence of mining risk does not eliminate project risk.
The central challenge becomes metallurgical performance. A historical waste deposit can have complex and variable chemical characteristics, requiring sophisticated processing and long-term testing before commercial-scale production can be assured. For Phalaborwa, lenders are likely to require extensive evidence that the proposed processing technology can perform reliably over sustained operating periods. That includes validated pilot-plant data, a completed residue-management strategy, long-duration reagent testing and clearly defined performance guarantees. These requirements will be particularly important as Rainbow moves toward the definitive feasibility study and potential project financing.
Phalaborwa Could Establish a New Rare Earth Recycling Model
If the technical challenges can be overcome, Phalaborwa could demonstrate how industrial residues can become economically significant sources of critical minerals The project combines a large existing waste resource with hydrometallurgical processing and a product strategy focused on separated rare earth oxides. Its potential to produce neodymium, praseodymium, dysprosium and terbium could give the development strategic relevance well beyond South Africa.
The project’s next major test will be whether pilot-plant performance can be translated into a reliable commercial process. Success would strengthen the case for using industrial waste as an alternative source of rare earths and could provide a model for recovering critical minerals from legacy processing sites elsewhere. With construction targeted for 2027 and first production around 2028, the definitive feasibility study will be pivotal in determining whether Phalaborwa can progress from a technically attractive waste-recovery concept into a bankable rare earth processing facility serving increasingly strategic global and European markets.
