“If they are simply left untouched, they will not provide much benefit. Before these materials can be used by people, many processes need to be carried out,” he said.

Prof. Edy also highlighted the potential of tailings, residues, slag, scrap, and electronic waste as secondary resources because they still contain valuable minerals and metals that can be recovered and reprocessed.

From Primary Resources to Mineral Separation

Prof. Edy explained that mineral processing today does not only focus on ores originating directly from nature as primary resources, but also on secondary resources such as tailings, residues, slag, and electronic waste that still contain valuable materials.

“Tailings, residues, slag, and electronic waste can become new resources to be reprocessed. Materials originating from nature are referred to as primary resources, while those originating from tailings and waste are considered secondary resources,” he said.

According to him, mineral processing always begins with characterization to understand the type, size, shape, and association of minerals within a material. This information serves as the basis for determining subsequent processes, including liberation through crushing and grinding. This stage is important because valuable minerals must first be liberated from gangue minerals before separation can take place.

“The first thing that must be understood in mineral processing is ore characterization. We need to understand what minerals are present, how they are associated, and the size of the minerals within the ore,” he said.

Once the minerals have been liberated, separation is carried out based on differences in physical properties, including density, magnetic properties, electrical properties, and surface characteristics, through gravity concentration, magnetic separation, electrostatic separation, and flotation. Prof. Edy added that process efficiency is strongly influenced by the grinding stage, which can account for approximately 40 to 60 percent of the processing cost required to produce concentrate.

“Determining how fine the particles should be ground is an important question in industrial applications,” he said.

These principles have also formed the basis of various studies conducted at ITB’s Mineral Processing Laboratory, including slurry rheology modification in primary tin ore processing and studies on the use of ceramic and steel grinding media for complex sulfide ores.

Bioflotation and the Utilization of Secondary Resources

Prof. Edy and his team have developed various mineral processing studies, ranging from the flotation of complex lead-zinc ores and the separation of tin ore using shaking tables and jigs to the use of bacteria as bioreagents. Since around 2014, bioflotation research has been developed to examine the effects of microorganisms on the surface properties of minerals such as chalcopyrite, pyrite, and silica. The results have shown promise, although further development is still required to improve recovery performance and grade.

“The process has been quite successful, but in terms of recovery performance and grade improvement, further development is still needed,” he said.

This biological approach has also been applied to red mud, a residue generated from the processing of bauxite into alumina that still contains iron. Due to its extremely fine particle size, the team developed a bioflocculation approach to encourage particles to form aggregates, making them easier to separate.

“Red mud can be utilized as a secondary source of iron minerals. Under certain conditions, bioflocculation can produce flocs with an iron grade suitable for use as feed material in iron extraction processes,” he said.

According to Prof. Edy, this research demonstrates that industrial residues still have the potential to be reprocessed as secondary resources, while also opening opportunities for more circular and sustainable mineral processing practices.

Metal Recovery and Circularity in the Metallurgical Industry

Prof. Edy also highlighted the potential of printed circuit boards or PCBs from electronic waste as secondary resources that still contain valuable metals, including copper. His team developed a separation process involving dismantling, shredding, sieving, magnetic and electrostatic separation, followed by concentration using a shaking table to produce material suitable for further extraction.

According to him, this approach shows that metal resources are no longer found only at mining sites, but also in electronic waste, industrial residues, and tailings. Therefore, achieving circularity in the metallurgical industry requires the involvement of the entire value chain, from geology and mining to mineral processing, metal extraction, alloying, and final product utilization.

“Circularity and sustainability in the production of metals and alloys will not function effectively without the support of all the components involved,” he said.

Prof. Edy added that future challenges will become increasingly complex due to diverse mineral characteristics, extremely fine particle sizes, and more intricate mineral associations. These conditions provide significant room for further development in mineral processing technology.

“Future technological challenges in mineral processing will be related to the mineralogical characteristics of ores and secondary resources, extremely fine mineral sizes, and increasingly complex physical associations between minerals. Therefore, there will still be considerable room for further development,” he said.

Profile of Prof. Ir. Edy Sanwani

Prof. Ir. Edy Sanwani, M.T., Ph.D., was born in Sampang on February 18, 1968. He is a Professor in the Metallurgical Engineering Research Group at ITB’s Faculty of Mining and Petroleum Engineering, with expertise in mineral processing and secondary resources. He completed his undergraduate degree in Metallurgical Engineering at ITB in 1992, followed by a master’s degree in Mining Engineering with a specialization in Coal Utilization Technology in 1997. He earned his Ph.D. from the Julius Kruttschnitt Mineral Research Centre at The University of Queensland, Australia, in 2006. In 2020, he completed ITB’s Professional Engineer Program.

Prof. Edy began his academic career at ITB in 1992. Over the years, he has served as Head of the Mineral Processing Laboratory, Head of the Metallurgical Engineering Undergraduate Program, Head of the Metallurgical Engineering Master’s Program, and Head of the Metallurgical Engineering Research Group at FTTM ITB. He was appointed Professor in 2024. His teaching and research activities cover mineral processing, coal processing, tailings, residues, slag, electronic waste, bioflotation, bioflocculation, and metal recovery from secondary resources. Prof. Edy has supervised more than one hundred undergraduate students as well as dozens of master’s and doctoral students, while also producing numerous publications and conducting collaborative research with government institutions and industry partners, including PT Aneka Tambang Tbk., PT Timah Tbk., PT Freeport Indonesia, and PT Bukit Asam Tbk.

Throughout his career, he has received several awards, including the Satyalancana Karya Satya for 10, 20, and 30 years of service, ITB’s 25-Year Service Award, the BIG MIND Innovation Award, and the Best Poster Award at the 2015 International Biohydrometallurgy Symposium. He also holds professional certifications as an Insinyur Profesional Utama, a Professional Engineer, and a Certified Educator.

For Prof. Edy, mineral processing is not merely about utilizing primary resources, but also about developing the capability to recover and reuse residual materials so that the metallurgical industry can become increasingly circular and sustainable.

“Mineral processing and secondary resources are part of the long process of supplying metals and alloys to support circularity and sustainability in the metallurgical industry,” he concluded.

Reporter: Merryta Kusumawati (Geodesy and Geomatics Engineering, 2021)