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Why metals matter in the modern world

- Wits University

Sehliselo Ndlovu, Professor of Chemical and Metallurgical Engineering at Wits, won a 'Science Oscar' at the NSTF-South32 Research Awards on 22 July 2022.

Wits Prof Selo Ndlovu centre wins the NSTF South32 Engineering Research Capacity Development Award

It was at a careers fair in matric that Professor Sehliselo ‘Selo’ Ndlovu first encountered metallurgical engineering – that metallurgy is related to the mining of metals, and that almost everything around us has passed through some metallurgical process. She had always been drawn to mathematics, physics and inorganic chemistry in high school and was fascinated with processing different materials to make products.

“When I saw how the chemical and physical characteristic of metals can be manipulated to extract metals from ores, and move from a solid rock to a solid metal, and I started connecting it to all that I had learnt in high school, I was captivated. I felt this was where I wanted to make a contribution in the future,” says Ndlovu.

Fast-forward 30-odd years and Ndlovu is now Professor of Chemical and Metallurgical Engineering at Wits University, and DSI/NRF SARChI Research Chair in Hydrometallurgy and Sustainable Development. Ndlovu won the 2021/22 NSTF-South32 Engineering Research Capacity Development Award, which recognises an individual contribution to SET over the last five to ten years. The award recognises Ndlovu’s work in hydrometallurgical engineering, which focuses on developing processes and building capacity to ensure a sustainable supply of metals for the extractive metallurgical industry in future.

But why do metals matter? Metallurgical research like Ndlovu’s helps ensure that metals can continue to be extracted in future – metals that the South African and global economy rely on.

“My research in extractive metallurgy involves creating new knowledge, processes and technologies for the hydrometallurgical extraction of  precious metals such as those of the platinum group metals [platinum, palladium, and rhodium],  gold, and other critical metals like cobalt and vanadium – from mined ores,” says Ndlovu, who has also graduated more than 40 PhD and MSc students.

That some of Ndlovu’s research has been patented for future commercialisation is evidence of her innovation. She engineered a novel process to recover platinum, palladium, and rhodium from spent autocatalytic convertors (SACs) – these are the richest platinum group metals secondary resource.

Ndlovu’s process by-passes the high energy smelting step commonly used and is purely hydrometallurgical. The chemicals used in the process effectively dissolve the metals at lower temperatures compared to the current process and practices in most existing recycling facilities.

The Intellectual Property generated in the project culminated in the establishment of a Wits affiliated spin-off company called AltMet (Pty) Ltd, founded by an MSc student whom Ndlovu supervised. The company is now on the radar of Gauteng Provincial Government for location in the OR Tambo Platinum Special Economic Zone currently under construction.

Clearly, metals matter because they play a role in all the technological advancements around us. “I think people tend to forget this and minimise the value of metals,” says Ndlovu. “This NSTF-South32 award says metals matter and, furthermore, those involved in extracting, processing and engineering metallic components also matter.”