Saline Used to Separate Metals from Waste
Similar to how a prism transforms white light into a spectrum of colors by isolating different wavelengths, metals can also be distinguished from each other through their individual properties. Yet, the existing techniques for separating metals are slow and rely heavily on chemicals and energy.
Due to this problem, a group of scientists from the Pacific Northwest National Laboratory under the Department of Energy have made a breakthrough in recovering essential metals from electronic waste by implementing an innovative mixed-salt water solution.
Heading the research efforts, scientist Qingpu Wang began a collaborative project focusing on the extraction of manganese, magnesium, dysprosium, and neodymium. His method involves dissolving the electronic waste material housing these elements in a series of dynamic reaction chambers, as highlighted in an official statement.
The Method
In this process, metals exhibit unique behaviors when introduced into a reaction chamber where two distinct liquids converge. The dissolved metals solidify at varying paces, enabling scientists to effectively isolate and refine them.
“Our goal is to develop an environmentally friendly and scalable separation process to recover valuable minerals from e-waste,” said Wang. “Here we showed that we can spatially separate and recover nearly pure rare earth elements without complex, expensive reagents or time-consuming processes.”
In February, a team of scientists achieved a major milestone, managing to extract neodymium and dysprosium from a blended solution. Utilizing their new technique, the separation procedure was completed in just four hours, marking a significant improvement over the traditional method which usually takes up to 30 hours.
The research team is also investigating opportunities to extract magnesium from seawater, mining waste, and salt lake brines to expand to other industries.
“Next, we are modifying the design of our reactor to recover a larger amount of product efficiently,” he added.
Extracting Manganese from Simulated Battery Waste
Moving forward, the primary objective for Wang is to enhance the reactor design to increase the recovery yield of the product.
Expanding upon those findings and implementing an additional method, Wang collaborated with materials scientist Elias Nakouzi to successfully extract highly pure manganese from a solution designed to replicate dissolved lithium-ion battery waste.
Incorporating a gel-based method hinged on exploiting the varied transport and reactivity rates of the metals present in the sample. “The beauty in this process is its simplicity,” Nakouzi stated. “Rather than relying on high-cost or specialty materials, we pared things back to thinking about the basics of ion behavior. And that’s where we found inspiration.”
The team is broadening the research scope and is set to elevate the process with the introduction of a fresh initiative known as Non-Equilibrium Transport Driven Separations (NETS) at PNNL. This initiative will, “develop environmentally friendly new separations to provide a robust, domestic supply chain of critical minerals and rare earth elements.”
“We expect this approach to be broadly relevant to chemical separations from complex feed streams and diverse chemistries—enabling more sustainable materials extraction and processing,” Nakouzi concluded.
