Two young South Africans are among the 16 engineers hailing from seven countries in Africa who have been shortlisted for the prestigious Africa Prize for Engineering Innovation.
University of the Witwatersrand chemical engineering research fellow Collins Saguru has developed AltMet, an economical, environmentally sustainable process to recover and reuse precious metals found in the autocatalytic converters of petrol and diesel vehicles.
“This recycling process addresses the demand for precious platinum-group metals (PGMs) in a way that is profitable and environmentally sustainable,” he said of his invention.
An autocatalytic converter reduces the toxicity of gases emitted by vehicles’ exhaust pipes and contains PGMs, which are valuable and useful for industrial processes. PGMs are also on the European Union’s critical materials list.
Saguru dismantles used autocatalytic converters, crushes and leeches them before extracting the PGMs. Aluminium and cerium are also extracted during this process.
While other recycling methods exist, they require high heat. Saguru’s method uses much lower temperatures, which makes the process more affordable and emits fewer toxic gases. His process uses chemical reagents, which are cheap, relatively common and environ- ment friendly.
Meanwhile, nuclear physicist Shalton Mothwa has been recognised for his Aeon Power Bag invention, which allows users to charge their phones and tablets on the go by converting radio or telecommunications waves and solar energy into power.
The lightweight backpack contains a unit that harvests radio waves in the surrounding environment and converts them into electricity. When radio signals are low, the solar charging unit kicks in.