Eco-friendly tungsten recovered from semiconductor waste

Researchers from Pohang University of Science and Technology (POSTECH) have unveiled an eco-friendly method to extract rare metals from semiconductor waste; their approach recovers tungsten and also assessed its economic viability, offering a sustainable solution for waste management in the tech industry.

Professor Jeehoon Han from the Department of Chemical Engineering led a team of researchers to pioneer the environmentally friendly and cost-effective process for tungsten recovery. Their research findings have been published in the journal ACS Sustainable Chemistry & Engineering.

Tungsten has many uses in electronics, semiconductors, aviation and automotive industries. Due to its rarity and the limited number of countries where it can be mined, research into recovering metals from industrial waste has become increasingly important. To prepare for the depletion of these metal resources, recovering metals from industrial wastewater is crucial. Industrial wastewater, if not properly treated, can impact water quality and soil, making this field of research a promising solution for resource recovery and environmental protection.

The researchers used bioleaching to recover tungsten from wastewater generated by the semiconductor manufacturing industry and assessed the economic feasibility of the technology. Microorganisms, which can derive energy necessary for survival and growth from metals, dissolve metals from ores or waste using their natural capabilities. This method, compared to traditional chemical processes, has a lower environmental impact and can extract metals at low energy and cost.

The researchers used the fungus Penicillium simplicissimum, commonly found in soil, air and plants, to dissolve tungsten and other metals. Following bioleaching, they recovered tungsten from the solution using activated carbon-based adsorption-desorption and ammonium paratungstate (APT) precipitation.

Economic analysis revealed that the activated carbon-based adsorption-desorption process was 7% cheaper than the precipitation process. The study also found that improving microbial strain adaptation and growth, as well as reducing reaction time, were crucial for enhancing process efficiency. The research confirmed the economic feasibility of an environmentally friendly process for treating semiconductor industry wastewater, highlighting its significance in preventing environmental pollution and recycling resources.

“Our study demonstrates the economic and industrial feasibility of an eco-friendly bioleaching process for tungsten recovery,” Han said.

The researchers aim to enhance the economic viability of this process by developing high-efficiency microbial strains.

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