Do not be fooled by the calm and cordial demeanor of chemical engineer Virginia Sampaio Teixeira Ciminelli. She is a fighter who keeps coming up with new ideas. For more than 15 years, she has been arguing that the exploitation of natural resources should promote more prosperity for the people living in the surrounding areas. A mine, for example, is part of a cultural and political space — in other words, it is a territory. The challenges of defending this concept of resource sharing have not been able to stop her work on this and other initiatives, such as a training program for engineering students that reinforces the skills needed to work in multidisciplinary and multicultural environments.
Hydrometallurgy
Institution
Federal University of Minas Gerais (UFMG)
Education
Undergraduate degree in chemical engineering and master’s degree in metallurgical and mining engineering from UFMG, PhD in mineral processing from Pennsylvania State University, USA (1987)
Scientific output
141 scientific articles, 6 books, 6 patents granted
Born in Belo Horizonte, the mother of two daughters — Camila, a lawyer, and Ana Luíza, a cardiologist — has a reputation for forging new paths. In 1995, she was the first female professor at the UFMG School of Engineering; in 2009, she was the first woman elected to the engineering division of the Brazilian Academy of Sciences (ABC); in 2013, she was elected to the National Academy of Engineering (ANE) in Brazil; in 2014, she was elected to the National Academy of Engineering (NAE) in the USA; and in 2021 she was recognized as Engineer of the Year by the Minas Gerais Society of Engineering. “I like to stay in my corner, concentrating on my work, but I’m not afraid to take a stand, and if it’s unavoidable, I never shy away from confrontation,” she said in an interview conducted by video call, recounting the challenges she has faced and achievements she has made.
Your research, as you yourself have already stated, is guided by the theme of water. What does that mean, exactly?
There are two major milestones in my career: the Millennium Institute – Water: a Mineral Vision, and the Acqua INCT [National Institute of Science and Technology]. At these research centers we looked at water from the very beginning of the ore exploitation process, during mining, when the pit is being excavated. The water that appears at this initial moment is used by the mine itself or in other projects, and often by the community. The water goes through the industrial process and then must return to nature with a certain level of quality. With this common thread, we tried to investigate what happens to this water and how it could be better used. Industrial processes generally involve high levels of water recirculation and have to comply with quality limits established by legislation, but it is important to draw attention to this water as an environment that harbors aquatic organisms, whose richness and distribution provide a range of ecosystem services. Water must also be seen from these other angles, as a home for biodiversity and as an element of cultural and social integration.
Could you explain the relationship between mineral resources and territory?
Mineral resources need to be seen as a means of promoting sustainable prosperity in a territory, transcending the lifespan of the mining project. I have been on this concept, which already exists in other countries, for about 15 years with my husband Renato Ciminelli, who is also a chemical engineer. In Brazil, it is very difficult to foster and implement long-term changes. We have seen this in practice. A few years ago, we selected three municipalities with large iron ore mining projects in the state of Minas Gerais — Conselheiro Lafaiete, Congonhas, and Ouro Branco — for a pilot project. The objective was to empower local communities and stimulate economic diversification. We created a reference center for agriculture in mining territories and carried out environmental education activities for children in the region, but the work was interrupted by changes in government.
Léo Ramos Chaves / Revista Pesquisa FAPESPThe CBMM mine, in Araxá: where niobium anodes (the negative pole of a battery) are recycledLéo Ramos Chaves / Revista Pesquisa FAPESP
How can we promote this territorial perspective of mining?
We need to generate data, use all the technologies available to us, and involve companies, the authorities, research institutions, and especially local communities. Change is slow, but the SDGs [Sustainable Development Goals set by the United Nations in 2015] and ESG [environment, social, and governance] can induce a change in mentality. Large projects, not only in mining but also in construction, agriculture, electricity, and other sectors, need to reassess how they share the benefits of using natural resources. It is common for major projects to attract thousands of workers, forming population centers that expose an unacceptable contrast between the richness of the enterprise and the misery of those on the peripheries, which are growing rapidly.
How can your area, hydrometallurgy, help achieve these aims?
By improving processes and taking a broader look at mining. This is critical because mining itself is not a sustainable activity. The mineral resource is finite and is gone once it is removed from nature. Because ore is coming from increasingly complex sources and we are having to make use of tailings and waste to reduce environmental impacts, hydrometallurgy has become a very interesting option, not to mention pyrometallurgy, which involves processing at high temperatures, and electrometallurgy, which is based on the application of electric currents. These approaches are often complementary, such as in the extraction of zinc and lithium. The first stage is pyrometallurgical, then there is a hydrometallurgical stage, and the final phase is electrometallurgical.
How does the hydrometallurgical approach usually work?
It encompasses processes carried out in an aqueous medium with a view to obtaining metal products, for example, aluminum, copper, gold, rare earth metals, zinc, lithium, nickel, and cobalt, as well as inputs for manufacturing fertilizers, such as phosphoric acid. There are various applications for hydrometallurgy products in materials used in daily life and in industrial environments. Aluminum oxide, or alumina, is used in the production of aluminum metal, but also for refractory materials, ceramics, abrasives, medicines, and cosmetics. There are two steps that characterize the hydrometallurgical processes. One is selective dissolution, in which the element of interest is separated from the others present in the ores or other sources, such as scrap, mining tailings, or electronic waste. In the second, the dissolved metal is recovered from the aqueous medium in the form of metal or a metal product. With the industrial production processes of aluminum oxide and gold implemented at the end of the nineteenth century, hydrometallurgy began to make a name for itself.
What makes hydrometallurgy such an attractive option?
Firstly, its ability to selectively extract tiny amounts of metals from diverse sources, even if they are very heterogeneous and complex. These are adjectives that apply to the currently available ores, which are generally becoming poorer and more complex. From one ton of ore, it is normally possible to extract 0.4 grams of gold or 10 to 20 kilograms of copper. Waste electronic components, such as printed circuit boards, are sources of gold and copper, but in this case, the metal of interest is also a minor part in an often complex and heterogeneous mix. The extraction process must be accurate and selective. The demand for high-performance mineral-based materials, sometimes tailor-made for technological applications, requires greater control of morphological characteristics, purity, size — on a nanometric scale — and product homogeneity. The processes involved in aqueous media, typical of hydrometallurgy, meet these demands.
Environmental performance has become a key factor in a product’s market competitiveness. It is an irreversible path
Is it possible to extract gold with water and without mercury?
Yes, using a hydrometallurgical process. Illegal mining is linked to inequality and poverty, economic interests, the absence of public authorities, and frequently, crime. The predominant technique in artisanal mercury mining involves forming a mercury-gold alloy, also known as an amalgam, to separate the gold from other minerals, before burning the mercury off. The problem is that mercury — even in tiny amounts and only slightly higher than natural levels — can have enormous impacts on the environment, biota, and human health. Because there is currently no widely adopted technology for recovering the mercury used in mining, it is simply released into the environment. The increase in illegal mining, particularly in the Amazon in Brazil and in neighboring countries, must be dealt with strongly. There are other technologies, such as a hydrometallurgical approach known as leaching [the process of extracting a substance from a solid medium through continuous dissolution] in an aqueous medium, which is more efficient and has less of an environmental impact.
Is hydrometallurgy more environmentally sustainable than other techniques?
No. All methods, if well planned and executed, can achieve high environmental performance, but they will always have some sort of impact. Which approach to choose depends on the cost-benefit ratio. Mining company AngloGold Ashanti uses a pyrometallurgical process in Nova Lima and a hydrometallurgical process in Santa Bárbara, with the same objective of extracting gold from refractory ores. In both cases, the aim is to achieve the best economic and environmental performance, considering not only the products but also the waste. The Morro Agudo mine, owned by Nexa Resources, produces zero waste. The main product is zinc concentrate, and the process used to generate waste, including toxic metals. The company optimized its process for recovering lead, which is now exported. What remains — the tailings predominantly contain dolomite — is used as a soil acidity corrector in agriculture. This is not always possible, but it is the future: maximizing the use of natural resources, optimizing energy use, and minimizing environmental impact.
What have you been doing with the private sector?
We are working on long-term environmental projects with companies such as Kinross Brasil Mineração and AngloGold Ashanti, on zinc electrorecovery with Nexa Resources, and as part of a consortium of foreign companies managed by Amira International. We started a project with CBMM [Brazilian Metallurgy and Mining Company] to recycle niobium from anodes [the negative pole of a battery]. Environmental performance in recycling and decarbonization, for example, is now required throughout the production chain, from both suppliers and customers. In other words, environmental performance has become a key factor in a product’s market competitiveness. This, in my opinion, is an irreversible path. Several research projects with students from companies have led to improvements in industrial processes, including a long-term electrometallurgy project managed by Amira Internacional with a consortium of companies from Brazil and abroad. Thanks to this experience and the excellent scientific results yielded for the company involved (Nexa Resources), we have just signed a contract with Befesa Zinc Metal, which only produces zinc from recyclable sources, with a view to improving the company’s plant in the USA.
How do you interact with the private sector?
It depends a lot on the person doing the interacting. A good relationship starts with respect from both parties. The company must respect me as a researcher and I must understand and respect the interests of the company, which also has to be willing to work with us on relevant scientific problems and share information. Unfortunately, this does not always happen, due to fear of sharing what they consider technological secrets, among various other reasons. But the situation is changing and nowadays many companies want the results of these partnerships to be published in high-impact scientific publications as a way of raising their reputation in the eyes of shareholders and the general public. I’ll give you an example. I had never worked with arsenic when Rio Paracatu Mineração, now called Kinross Brasil Mineração, called me in the late 1990s. The company produces gold, which is associated with minerals containing arsenic, a highly toxic chemical element. The company wanted to find a safe way to dispose of sulphide concentrate with arsenic generated in the gold extraction process. The idea was to use soil from the region that could act as a chemical barrier to stop the element from leaking into the environment. We got to work identifying soils rich in iron and aluminum, which are very efficient at retaining arsenic. The problem was also the subject of a study by a PhD student working at the Brazilian Synchrotron Light Laboratory (LNLS) in Campinas, who identified how arsenic binds to aluminum oxides. It was one of the pioneering studies that associated experimental and theoretical molecular modeling, which had previously been recognized abroad, and it also triggered the formation of a partnership with Hélio Anderson Duarte’s theoretical chemistry group [at UFMG], which continues to this day.
Personal archiveCiminelli with Kwadwo Osseo-Asare, her PhD supervisor, during her time at the USA’s National Academy of Engineering in 1994Personal archive
How did you solve the arsenic problem?
We recently examined soil samples using high-resolution microscopy and observed very high concentrations of arsenic in soils, but it was trapped inside iron oxyhydroxide nanocrystals, with low bioavailability. What that means is that even if someone is exposed or inadvertently ingests the material, only small amounts of arsenic will be released into the body, at levels that do not pose any significant health risk. For companies operating in the region, this information is extremely important because it prevents gold extraction from being suspended. Arsenic contamination could also have serious impacts on the local community, which is reliant on agriculture. The information was shared with the residents of Paracatu, in the state of Minas Gerais, who were worried about the risk of contamination by arsenic, as well as with the public authorities. As is common in medium-to long-term research with the private sector, work that began with the aim of addressing a specific company issue has progressed as research and the knowledge has been returned to stakeholders. The national and international divisions of Kinross Gold, headquartered in Canada, encourage publications in high-impact scientific journals. It is a way of disseminating good practices and strengthening the company’s image.
What is it like to make deals with companies while at a public university?
When I started in 1988, the university was really resistant, but that has changed. Now the government itself issues calls for proposals through this kind of collaboration and demands that researchers show how their research has positively impacted society. It is also clear that the private sector raises challenging problems, which improve our work and allow us to make progress, as well as offering resources to research groups. My biggest scientific contributions have come from questions originally asked by companies. My group has always been multidisciplinary, including students from pharmacy, biology, chemistry, mechanical engineering, chemistry, and metallurgy. In 1987, when I returned from my PhD in the USA, I naively said “I want to do the same thing here.” Despite the differences, our human capital is of the same quality. I have always invested in the international experience of my students, long before Science without Borders [a federally funded foreign exchange program for university students that was in place from 2011 to 2017]. I always brought many professors over from other countries and I had many fruitful partnerships with companies that allowed me to make advances in scientific knowledge and student training.
What multidisciplinary studies have you worked on?
After returning from the USA, I started working in biohydrometallurgy, which uses microorganisms that catalyze chemical reactions to produce metals. I used materials based on algae and poultry waste as biosorbents to treat effluents. The first pilot plant in the country to use biohydrometallurgy was built at the former Morro Velho mine in Nova Lima, and was the subject of a master’s thesis by a student who is now a successful entrepreneur. I was involved in the implementation of the first industrial unit in Brazil to use a wetland system for the treatment of acid mine drainage. The process uses artificial lakes containing plants and microorganisms that treat the acid effluents from a mine. The project, located in the same former mine, continued operating until recently. More wide-reaching work was done in collaboration with colleagues from ecology and biology, led by Francisco Barbosa of UFMG and José Galizia Tundisi of UFSCar [Federal University of São Carlos], at INCT-Acqua.
Are the changes you propose generally well accepted by mining and metallurgical companies?Several changes are part of broader movements taking place around the world. Environmental concerns and energy transition are major drivers of innovation across all industrial sectors. The impacts of the mineral sector will not be efficiently resolved if we focus solely on one production chain. Reusing waste, for example, due to the large volume and other characteristics, requires interaction with other sectors, such as the materials industry, agriculture, and construction. More and more companies are realizing that adopting more environmentally friendly technologies and more efficient uses of water and other natural resources is financially beneficial. This has proven to be the case during periods of water scarcity, for example. Investing in sustainable processes pays for itself while also offering advantages in environmental governance and competitiveness. As a citizen, I would like to see the implementation of ambitious national development projects that make better use of our scientists, engineers, and researchers, and add greater value to our mineral resources — in the production of steel, batteries, or electronic devices, for example. We also need to reassess certain assumptions. Mining has what we call locational rigidity, since it is impossible to move a mine to another location. But even so, decisions on the uses of these resources must not neglect the other natural riches and cultural values of a region. Is it really necessary to extract metals in the Curral Mountains, a symbol of Belo Horizonte, or in the Complexo Santuario do Caraça Mountains, which are a natural and cultural heritage site? Or in indigenous lands? Not only mining, but all major engineering projects, including urban ones, have major long-term repercussions and impacts and should consider these limits and values.
I always take a stand, but recognition also comes from the people who notice you among the crowd and see the value in your work
What are you most proud of?
Definitely seeing the careers and accomplishments of my former students. I have been lucky enough to help train world-class engineers and researchers, who now work in Brazil and abroad for companies, at research centers, or running their own businesses. To date, I have supervised 61 master’s and PhD students and 20 postdocs, represented here by Cláudia Lima Caldeira and Daniel Majuste, my colleagues in the department. I have worked with Cláudia for my entire career as a researcher, on all of the projects I mentioned earlier. Daniel helped establish electrometallurgy and expanded the group’s operations with urban mining, to encourage the reuse of metals from waste electrical and electronic devices. There are many possible approaches. On trips to Europe, I saw that it was common to grind and process all the material, but we thought of a different method. We tried to segregate the constituents while they are still in solid form, to minimize subsequent chemical steps. We also want to reuse plastic and glass.
One of your recent projects relates to training engineers.
Yes. Since 2019, the UFMG School of Engineering has been part of an international Grand Challenges Scholar Program (GCSP), created by the USA’s National Academy of Engineering. The search for solutions to the challenges of the twenty-first century requires engineers with a solid foundation of knowledge and an entrepreneurial spirit, but also the ability to work in multidisciplinary teams, multicultural environments, and above all, an understanding of engineering’s social responsibility. The program is now in its second group of 30 students and the experience has been very enriching, establishing a locus for professors from different areas of engineering based on the common objectives of training new professionals. It attracts young engineers with diverse experiences and skills, which often remain hidden and unexplored during university courses. At UFMG, the program has taken a new approach, immersing students and mentors in local government or a company to understand its problems and propose solutions. It is fascinating to see how, in just a short period of time, students develop the multidisciplinary techniques needed to solve real problems and discover their own ability to analyze and propose solutions to new issues. We have recently signed an agreement with Vale that will give students this type of experience at their innovation hub. We intend to expand these partnerships and support methods.
What is the situation like for women in your field?
I have seen significant growth in university access in recent years, not only for women but also for other minorities, thanks to inclusion programs. Many turn out to be exceptional students and professionals who excel after leaving university. In my research group there have always been more women, but female engineers are still at a disadvantage in terms of representation in science and engineering academies or in the highest categories of researchers at the CNPq [Brazilian National Council for Scientific and Technological Development]. There is still a long way to go.
Did you face resistance before you conquered your own space?
I have faced and continue to face resistance. Both structurally, through barriers to people, projects, or ideas, and in the intense resistance of competitive environments, as well as feeling the resistance faced by those around me. But I personally can say that I thrive on challenges. I always take a stand and defend my ideas and principles, I’m independent, and when it is unavoidable, I do not shy away from confrontation. Recognition comes from the people who notice you among the crowd and see the value in your work.
Who were they?
Many people have inspired, taught, and supported me at special moments, but there are two that really deserve a mention. The first is Evandro Mirra [1943–2018], a former president of the CNPq who was a man of unique culture and brilliance. The other is my PhD advisor, Kwadwo Osseo-Asare, who taught me what it means to be a scientist. He is a brilliant, thought-provoking, demanding mind with a great sense of humor.
