Circular hydrometallurgy approaches towards more sustainable processing of critical minerals

Circular hydrometallurgy is an emerging approach in metal extraction and recovery that applies circular economy principles (reduce, reuse, recycle, and recover) to traditional hydrometallurgical processes. It is a sustainable, closed-loop approach to metal recovery that turns waste into a resource, integrating hydrometallurgical science with circular economy thinking.

Circular hydrometallurgy is becoming a cornerstone perspective for extractive metallurgical processes, and in particular for the processing of critical minerals, and their associated metals and materials. In a keynote lecture at Critical Minerals '26, Jacques Eksteen, a Professor in the WA School of Mines, at Curtin University, Australia, will review examples in the development of novel processes for some critical minerals essential in the Energy Transition, such as nickel, cobalt and copper, and associated precious metals such as PGMs, gold and silver. 

The Energy Transition towards cleaner forms of non-fossil energy requires a complete rethink as to how we design our processes from the perspectives of energy utilisation, the use of benign reagents, the recycling and reuse of reagents and water, and valorisation of traditional waste products. The circularity around waste products, water and reagents reuse will be emphasised, while still ensuring economic feasibility.

Prof. Eksteen will provide examples where amino acids have been used in hydrometallurgical pathways to extract and refine a variety of critical metals from their ores, tailings, concentrates and from various technospheric (i.e. human-derived) waste materials. This will be an interesting precurser to the keynote lecture from Prof. Chun-Xia Zhao. who will show how her team at the University of Adelaide are developing designer peptides, short chains of amino acids, tailored for specific mineral binding and flotation applications.

Jacques Eksteen is the Manager of the Critical Minerals Metals and Materials for the Energy Transition research group at Curtin University. He is also the Interim Research Director for the Critical Metals for Critical Industries CRC. In addition, he was the Program Lead for Technology Readiness Level Progression in the Critical Minerals and Resources Technology Trailblazer, and held the roles Chief Scientist, Chief Operating Officer, and Research Director  of the Future Battery Industries Cooperative Research Centre Ltd. He was Director of the Gold Technology Group and project manager of the AMIRA 420 project from 2012 to 2019. Jacques holds a PhD in Extractive Metallurgical Engineering and has 32 years of experience in industry and academia. He has published over 200 journal papers and conference proceedings and is a listed inventor on 10 patent families.

#CriticalMinerals26

Cornish Lithium becomes first company to produce lithium hydroxide mined and refined in the UK

The monthly Cornish Mining Sundowner postings include news of any mining developments down here in Cornwall.  As I will be in Cape Town this month I will miss the sundowner, so I am happy to report here of the exciting new development at Cornish Lithium's Trelavour demonstration plant, near St. Austell in East Cornwall, where in a first for the UK, it has started production of refined lithium hydroxide monohydrate (LHM),  extracted from zinnwaldite, a lithium containing mica found in the decomposed granite which forms kaolin, and mined in the St. Austell region as china clay. LHM is a key raw material for advanced, high-energy lithium-ion batteries which form the foundations of nearly all modern-day electronics on which we all rely - from electric vehicles (EVs) and smartphones to energy storage and drone technology.

Cornwall is home to the largest lithium deposits in Europe and has enough lithium to power at least 50% of all EVs expected to be produced in the UK by 2030. This announcement marks a major advance in UK industrial capability that will help secure a domestic supply of a key material for UK industry. Currently over 60-70% of the world’s lithium refining takes place in China.‌‌‌​​‍‌‌‌‍‍‌‍‌‌‌‍‌​‍‌‌​​‌​‌​​‍‌‌​​‌​‌​​‍‌‌​​‍​​‍​​‍​‌‌‍​​‌‌‌‍‌‌​​​​‌‍​‌​‍‌​‍​‌‍​‍​​​‍‌‌​​‍​​‍​‍‌‌​‌‌‌​‌​​‍‍‌‌​‌‍‌‌‌‍​‌‌​​‍‌‍‌​​‌‍‌‌‌​‍‌​‌​​‌‍‌‌‌‍​‌‌​‌‍‍‌‌‌‍‌‍‌‌​‌‌​​‌‌‌‌‍​‍‌‍​‌‍‍‌‌​‌‍‍​‌‍‌‌‌‍‌​​‍​‍‌‌ 

In an end-to-end industrial process, the company is re-purposing a former china clay quarry and, using innovative low-carbon processing technology, producing refined LHM on a single brownfield industrial site at Trelavour. The custom-built facility incorporates all processing stages from crushing and grinding the rock, separation of the lithium-bearing minerals and processing of these minerals to produce a refined lithium hydroxide monohydrate.

Launched only a year ago, the plant uses patented, low-carbon processing technology developed over many years of intensive research and development. In early 2025, Cornish Lithium successfully acquired full intellectual property and associated patents from Australian company Lepidico. The Lepidico process has shown to be highly effective and has now been fully optimised by improvements made at the Demonstration Plant. Cornish Lithium plans to market the technology internationally given the success that has been achieved in recent months. The new technology, incorporated into the demonstration plant operates at atmospheric pressure and at moderate temperature, significantly reducing carbon emissions and helping to set a new sustainability standard in the sector

Following the success of the demonstration plant, Cornish Lithium plans to build a full-scale lithium processing and refining plant with an annual capacity of up to 10,000 tonnes of LHM, which is expected to commence full-scale production in 2029.

Let's not forget, however, that another company in East Cornwall, British Lithium, is also extracting lithium from the decomposed granite at a nearby china clay pit, owned by Imerys, a French multinational company, which, in 2023, acquired an 80% stake in British Lithium. The transaction brought together Imerys’ expertise in mining, R&D and process development capabilities, as well as its lithium mineral resources, with British Lithium’s bespoke technology and state-of-the-art lithium pilot plant, which last year produced battery-grade lithium carbonate.

Lithium carbonate is a major product, the foundation of the lithium industry, but for many high-end EV batteries lithium hydroxide is the preferred precursor, so refining to hydroxide gives access to these higher value battery markets. Cornish Lithium's aim of producing battery-grade lithium hydroxide signals that they are aiming at a more advanced stage of processing and potentially higher margin / higher specification product. 

By contrast, British Lithium’s achievement is important, but is at the carbonate stage. The step to hydroxide is one further stage of processing, so in principle Cornish Lithium is one further step along the chain. The fact that Cornish Lithium can produce lithium hydroxide domestically is a “first” in the UK context and by-passing a lithium carbonate stage aligns Cornwall with the trend for high-performance battery chemistries.

Weir Minerals expands its role as a total process partner in comminution and beyond

We are pleased that Weir Minerals, who sponsored Comminution '25, will be sponsoring Comminution '27 in 18 months time. The company has come a long way over the last 20 years, when it was best known for slurry-handling equipment, with hydrocyclones, pumps, and valves its core offerings.

Weir marketing their hydrocyclones at Hydrocyclones '03 in Cape Town

The company has significantly broadened into comminution equipment over the past decade and now positions itself as a "total process partner" across the entire minerals processing flowsheet, including comminution, classification, transport, and tailings management. Weir has invested heavily in, and now manufactures or supports, several categories of comminution machinery.

Weir’s Enduron® High Pressure Grinding Rolls (HPGR) line is central to its sustainability push, marketed as using up to 40% less energy than traditional grinding mills. To complement its Enduron® range of HPGRs, Weir has developed a robust range of crushers and screens under the same premium brand, now further strengthened by its in-house screening media. Weir’s large Enduron Elite double-deck banana screens have been in high demand, and will soon be produced at the company’s Alrode facility south of Johannesburg.

Large vibrating screens are vital to complement large capacity crushing plants and HPGR circuits and the Enduron Elite range is playing an important role in hard rock mining developments throughout Africa.

The latest generation of Weir’s Enduron cone crushers and jaw crushers has also just been introduced.

A key factor behind the success of Enduron HPGRs and the complementary crushers and screens in the circuit has been the rising cost of electricity, affecting not only South Africa but many other countries in Africa. Mines are adopting HPGR circuits as an energy efficient alternative to the traditional semi-autogenous grinding (SAG) mill circuits.

At Comminution '25 we were pleased to hear that the company has developed a new Process and Applications Academy, a training program designed to give graduates technical insights into processing equipment. 

The academy aims to impart essential technical knowledge to recent university graduates, ensuring they are prepared for their professional responsibilities. It is designed for graduate process engineers, mechanical engineers, metallurgists and chemical engineers. The inaugural academy also welcomed graduates in electrical and civil engineering, thereby remaining open to all graduates nominated by their respective line managers.

At the inaugural training session, the academy emphasised essential concepts, selection criteria and troubleshooting techniques, with a particular focus on comminution, slurry and dewatering pumps, wear-resistant products, valves and cyclone simulations. Additionally, the course addressed the integration of artificial intelligence into these processes, which is bringing together equipment expertise, metallurgy, and intelligent solutions to optimise entire circuits, not just machines. From real-time digital twins to predictive maintenance and mine-to-mill feedback loops, Weir's vision is helping reshape mining operations and we hope to see the company involved not only in Comminution '27 but also in MEI's inaugural conference, AI in Mineral Processing '27, which follows 2 months later in Cape Town.

#Comminution27

October summary; registration closure and a brief glimpse of dystopia

On the 13th of this month, I switched on my laptop only to discover there was no internet access. I reached for my phone to use mobile data- no signal there either.

It turned out to be a major outage affecting my broadband and mobile provider, Vodafone. Although it lasted only a few hours, it offered a brief glimpse into a dystopian scenario: a global outage triggered by a cyberattack or a huge coronal mass ejection. It was a stark reminder of just how dependent we’ve become on electronics in our daily lives.

Fortunately, the internet returned just in time for us to close registrations for Flotation '25, having reached full capacity at Cape Town’s Vineyard Hotel. This will be the largest MEI Conference in our long history, and we extend heartfelt thanks to the global community for their incredible response and continued support. If you missed out this time, stay connected with us here for updates, highlights, and news about future MEI conferences.

We are particularly excited about leaving for Cape Town in two weeks' time, as there will be a new member of the team with us, Amanda's son, Will, who will be serving his "apprenticeship" with MEI with a view to joining us in a few years time. So look out for Will if you are at the conference- you may recognise him as he was also at Flotation '07 eighteen years ago.

As soon as the dust settles on Flotation '25 we will be working on our next two conferences at the Vineyard, April's Physical Separation '26 and Mineral Processing Circuits '26. If you would like to submit abstracts to these conferences, the official deadline is tomorrow, but there is some latitude as we will not be drafting the programmes until later next month.

Gravity Mining to showcase advanced fine gravity separation technology at Physical Separation '26

We were delighted to welcome Gravity Mining Ltd as a first-time sponsor of an MEI event for the online conference Physical Separation '22, held at the height of the Covid pandemic. Now, we are pleased to announce that the company will join us again, this time in person, as a sponsor of Physical Separation '26, taking place next April in Cape Town.

Gravity Mining is the home of the original Mozley Multi Gravity Separator (MGS), a technology that has undergone significant refinement in recent years with a focus on reliability and user-friendliness. Technical Director Treve Mildren, who worked closely with MGS inventor Richard Mozley as a Design Engineer, founded Gravity Mining to build on Mozley’s legacy. The company has since continued to innovate in fine and ultra-fine mineral recovery.

Earlier this year, I had the opportunity to view the latest evolution of this technology, the massive C910 Multi Gravity Separator, at Gravity Mining’s new facility in Blackwater, near Redruth, Cornwall. Specifically designed for bulk commodities such as iron ore and chromite, the C910 enables the recovery of ultrafine minerals typically lost to tailings. Impressively, 70% of its components are sourced locally in Cornwall.

At the launch of the C910 MGS with Gravity Mining Directors
Colin Colino, and Treve and David Mildren

Headquartered in the historic hard rock mining region of Cornwall, in the far southwest of England, Gravity Mining maintains a strong export focus, with established dealers across key mining hubs worldwide. While the MGS has traditionally excelled in tin, tungsten, and tantalum applications, its use is expanding into areas such as chromite, barytes, waste recycling, and other sectors where fine gravity separation is essential. One particularly promising area for future growth is the recovery of fine free gold, a currently underdeveloped application for the MGS.

In addition to its flagship gravity separators, Gravity Mining also manufactures and supplies a broad range of supporting products, including Mozley Tables (Superpanners), Stirred Mills, Bottle Rollers and Peristaltic Pumps. The company collaborates closely with other original equipment manufacturers, producing High-Speed Centrifugal Concentrators, Spirals, and Shaking Tables to help optimise customer processes.

Gravity Mining is set to have a strong presence at Physical Separation '26, both as an exhibitor and through technical presentations on their latest developments.

A reminder to all prospective contributors: the abstract submission deadline for Physical Separation '26, as well as for Mineral Processing Circuits '26 (which follows immediately after), is the end of this week.

#PhysicalSeparation26

Memories of Nickel Processing '05, Cape Town

A week after Process Systems '05 (posting of 9th October) MEI ran another conference for the first time, Processing of Nickel Ores and Concentrates '05, the first of eventually four in the series. The event was held at Cape Town's Mount Nelson Hotel and was sponsored by Eurus Mineral Consultants.

The conference was attended by 35 delegates, and a short report was provided by Dr. Norman Lotter, of Falconbridge, Canada. Selected papers were published in Volume 19 Issue 12 of Minerals Engineering. 

A few photos from the event are shown below.