The RotowinnerTM Technology

About The Rotowinner TM

Revolutionizing Electrowinning Cell Design

Free Radical Process Design (FRPD) has developed a novel electrowinning technology (the Rotowinner™) that presents a groundbreaking advancement in electrowinning with its innovative scraped rotating electrode cell.

This cutting-edge technology offers exceptional mass transport rates and compact design, making it a game-changer in various applications.

Design Features

The current design of the Rotowinner comprises a stationary anode, tailored to specific requirements, and a cylindrical cathode that rotates continuously.

What sets the Rotowinner TM apart from conventional electrowinning cells is its integration of innovative features, including direct scraping technology. This remarkable capability allows for uninterrupted harvesting of the product, streamlining the production process.

Moreover, the system incorporates a full reactor enclosure, prioritizing safety during operations and ensuring a secure environment for operators.

Direct scraping technology

Uninterrupted productivity

Heightened safety

Versatility Across Industries
The Rotowinner's versatility enables its application in various industries. From metal recovery in mining operations to water treatment and green hydrogen production, this technology offers sustainable solutions.
Compact and Efficient Design
The RotowinnerTM boasts a compact footprint, making it easily integratable into existing processes. Its high ratio of electrode surface area to catholyte volume enhances efficiency and minimizes installation costs
Continuous Product Harvesting
Unlike conventional electrowinning cells, the Rotowinner incorporates direct scraping technology. This feature allows for continuous product.
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Basic Operation Principles of the RotowinnerTM

Anode and Cathode Configuration

The Rotowinner consists of a stationary anode and a rotating cylindrical cathode, both made of a specific material based on the application.

Electrolyte Bath

The electrodes are immersed in an electrolyte bath, typically containing a solution with metal ions that need to be extracted or plated onto the cathode.

Cathode Rotation and Turbulence

The cylindrical cathode rotates continuously, generating turbulence within the electrolyte bath, enhancing mass transfer, and facilitating efficient electrochemical reactions.

Electrodeposition and Harvesting As the metal ions reach the cathode surface, they undergo electrochemical reduction, leading to the deposition of metal onto the rotating cathode. The direct scraping technology of the RotowinnerTM enables continuous product harvesting, eliminating the need for intermittent collection.

Case Studies

Explore how the RotowinnerTM System is revolutionizing various industries through our collection of compelling case studies.

Our groundbreaking technology is being developed for various applications including metal recovery, mine influenced water treatment, water softening, and green hydrogen production.

LME Grade 2 Copper Production using the RotowinnerTM

  Free Radical Process Design (FRPD) embarked on the development of the Rotowinner to address the challenges encountered in the conventional copper electrowinning process. Consequently, FRPD successfully constructed the first containerized RotowinnerTM demonstration plant in 2022. 

The core technology of electrowinning metals provides a wide scope for the RotowinnerTM to produce various metals.

The demonstration plant was operational at a South African base metal refinery (BMR) for 6 months. This plant was specifically designed to produce LME grade 2 copper from the BMR copper sulphate leachate feed and to purify process streams by removing undesired residual metals.

The RotowinnerTM technology demonstrated its potential to continuously produce final products while occupying a small footprint and requiring minimal operator intervention.

Through the Rotowinner TM technology, FRPD aims to revolutionize metal extraction and purification processes, offering enhanced efficiency, continuous production, and improved product quality, ultimately driving advancements in sustainable metal production.

B-grade Copper-winning
With trace metal removal by electro-stripping
Stream Purification
Base metal removal from ammonium sulphate solution
Demonstration Plant Operating Data
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ElectrosoftnerTM: The Salt-Free Water Softener Powered by the RotowinnerTM Technology

FRPD introduces the ElectrosoftnerTM, a cutting-edge salt-free water softener that effectively addresses temporary and permanent water hardness. Built upon the innovative RotowinnerTM technology, this modular unit operates in both continuous and batch-recycle modes, delivering softened water, hydrogen, and calcite/milk of magnesia mixture.

The ElectrosoftnerTM boasts economic advantages, including low energy requirements and zero waste generation. Its compact packaging ensures easy transport and handling, while the design allows for scalability, accommodating larger volumes of hard water for treatment. Experience efficient and sustainable water softening with the ElectrosoftnerTM from FRPD.

ElectrosoftnerTM: How it Works

Purification of Mine-Influenced Water

Liquors contaminated with environmentally harmful metals pose a significant risk to ecosystems and human health. At FRPD, we recognize the urgency to find sustainable and effective solutions for their treatment. That’s why we have embarked on the development of the RotowinnerTM application of mine influenced water treatment. This endeavor is aimed at transforming the way we mitigate the impact of these metals on our environment.
Purifying Mine-Water with Precision: the RotowinnerTM Team at Work

The RotowinnerTM Demonstration plant was deployed for purifying underground mine-water in the Northern Cape Province, South Africa.

The RotowinnerTM underwent continuous electrolysis of mine influenced brine water supplied from a Reverse Osmosis (RO) plant.

Both the harvested solid and treated water products from the RotowinnerTM Plant were thoroughly analyzed.

The solid product primarily consisted of hardness-causing species, with calcium (34%) and magnesium (64%) being the main components, alongside manganese (1%).

Scraped solids
Hardness-causing species (99%), Calcium (34%), Magnesium (64%), Manganese (1%)
Brine Water Purification
72% of total water hardness removed from feed water. 92% of calcium removed from feed water. 89% of manganese removed from feed water. 90% of mercury was removed from feed water. 90% of zinc removed from feed water.

The RotowinnerTM system treated a feed stream at a flow rate of 2.2 m3/h for approximately 8 hours, effectively processing approximately 16 m3 of water.

The results indicated that the RotowinnerTM is highly capable of treating mine influenced brine solution and effectively softening hard water without the need for additional chemicals.

At FRPD, we firmly believe in the importance of sustainability. The Rotowinner TM project aligns with our commitment to promoting a circular economy and reducing the reliance on traditional methods of mine influenced treatment, which often contribute to further environmental degradation.


By implementing the RotowinnerTM technology in mine influenced Water treatment, we aim to minimize the environmental footprint, optimize resource utilization, and foster a greener future.

Driving Sustainable Mine Influenced Water Treatment with The RotowinnerTM

Unlocking the Future of Precious Metals Extraction

At FRPD, we are dedicated to pioneering advancements in precious metal recovery. Our ongoing development efforts focus on utilizing the groundbreaking RotowinnerTM technology to extract precious metals from high and low concentration streams, while promoting sustainable recycling practices.

The RotowinnerTM technology, currently in development, holds immense potential for transforming the recovery process of precious metals from streams with low and high concentrations. By harnessing the unique capabilities of the RotowinnerTM system, we aim to maximize recovery yields and minimize resource waste.

Revolutionizing Precious Metal Recovery with the RotowinnerTM
Through continuous research and innovation, we are optimizing the RotowinnerTM technology to efficiently extract precious metals, such as gold, silver, and platinum, from low concentration streams. This breakthrough technology enables effective separation and recovery of these valuable resources, even from challenging feed materials..

As part of our commitment to sustainability, the RotowinnerTM technology aligns with our mission to promote recycling and reduce dependence on primary resource extraction. 

By recovering precious metals from low concentration streams, we contribute to the circular economy and minimize the environmental impact associated with traditional mining practices.

Reducing Reliance on Primary Resources with the RotowinnerTM
Empowering Industries with Sustainable and Efficient Precious Metal Recycling Solutions

Through our ongoing development efforts, we strive to unlock the full potential of the RotowinnerTM technology for precious metal recovery from low and high concentration streams.

By harnessing this innovative solution, we aim to provide industries with a more sustainable, efficient, and economically viable method for recycling precious metals.

Stay Connected

Stay connected with FRPD to stay updated on our progress as we continue to advance the RotowinnerTM technology in 

Precious metal recovery

Mine influenced water treatment 

Hydrogen Production 

Contact us today to learn more about our project and how we can work together to make a positive impact on our planet.