Gallium recycling: Pilot project launched in Saxony

Gallium is a strategically important element and the backbone of the semiconductor industry for mobile data transmission and optoelectronics applications. It is used in wafers (GaAs, GaN), electronic chips, and optical components such as LEDs and lasers. One kilogram of gallium currently costs around €1,000, and the price is rising. During industrial processing, a considerable amount of the raw material is already lost when etching or polishing processes remove material. The residues are sometimes highly diluted or the mixture is chemically complex, making recovery by conventional chemical means difficult. This is where the research of the Helmholtz Institute Freiberg for Resource Technology (HIF) of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) comes in. Using a biotechnological process, the wastewater from Freiberger Compound Materials is treated in an industrial-scale research facility and the gallium is recovered.

Gallium is considered a critical raw material that is essential for both the development of renewable energy sources and the development of energy-efficient systems. Efficient recycling technologies are needed to ensure the availability of gallium for high-tech applications in the future. The biotechnology department at HIF transfers biochemical principles and biological functional carriers to completely new applications, thus linking biotechnology with resource technology. Metals are recycled using biosorption, in which biomolecules with the ability to bind to specific ions or molecules are the key reagents. Siderophores have proven to be suitable for recovering gallium from industrial wastewater. Siderophores – Greek for “iron carriers” – are a group of around 500 low-molecular compounds that are characterized by the formation of stable complexes with iron ions. In nature, they are produced by numerous bacteria, fungi, and plant roots in order to absorb iron from the environment.

The lead HIF scientist is biochemistry engineer Dr. Rohan Jain: "We use the metal-binding properties of siderophores to recover gallium(III) ions from industrial wastewater, such as that produced during the production of GaAs wafers at Freiberg Compound Materials. We use two different siderophores to recover the gallium. Using a patented process, we dissolve the gallium from the siderophores so that both can be reused. Siderophores are a perfect, stable, and environmentally friendly tool for us."

In the investigations, the two siderophores used formed highly stable gallium-siderophore complexes. This result correlates with the observed high selectivity of the two siderophores towards gallium. In fact, gallium from two different process wastewater streams from wafer production could be bound as a complex at a rate of 100 percent. "Using various spectrometric methods (infrared and nuclear resonance) and density calculations, we determined how the gallium(III) ions are complexed, i.e., incorporated into a complex: We use a patented separation method to separate the gallium complex from the process wastewater. This enabled the gallium to be almost completely complexed and 95 percent recovered as a siderophore complex. We were able to demonstrate the reusability of the siderophores in over ten cycles without any loss of function," says Jain, describing the process.

The process has been successfully tested on a laboratory scale with a throughput of ten liters per day, and the pilot plant is now already handling 100 liters per day. Further pilot testing is being carried out at the semiconductor manufacturer Freiberger Compound Materials (FCM) GmbH. At the company's headquarters in Freiberg, the research plant is expected to process 1,000 to 2,000 liters per day soon. “We expect to learn about the scalability and economic efficiency of the process in an industrial environment,” says FCM chief technologist Dr. Stefan Eichler. Manufacturing companies in the high-tech industry typically generate between 10,000 and 300,000 liters of wastewater per day. In mining, the figure is as high as 20 million liters or more. In the German high-tech sector alone, two to five tons of gallium per year could be saved through recycling from wastewater, thereby reducing dependence on imports.

Rohan Jain and his team have already reached another milestone: starting October 1, 2025, they will receive spin-off funding from Helmholtz Enterprise in the amount of €230,000 for a period of just over a year. The Helmholtz Association's spin-off program finances the establishment of the founding team and the implementation of the start-up project. The SideroGaIn team was evaluated and selected by a jury consisting of venture capitalists and business representatives. “My team and I are particularly grateful to be able to scale up the technology and carry out the pre-commercial phase with an experienced industrial partner such as Freiberger Compound Materials,” says Jain.