Design Indaba 2015: jewellery items in this collection by South African designer Ashley Heather are made from silver salvaged from discarded electronic products.

The rings, necklaces, bracelets, earrings and cufflinks offered by Ashley Heather's eponymous brand are all made using recycled precious metal.

Heather works with a large metal refinery, which she claims is the only facility of its kind in Africa, that extracts the metals found on unwanted electronic circuit boards and produces a high-quality silver.

"Circuit boards use quite a bit of silver because it's a good conductor of electricity," Heather told Dezeen at the Design Indaba Expo where she presented her collection last month. "There's a huge amount of circuit boards currently going to the landfill. We're processing them, reclaiming all the precious metals."

The refining process begins by dismantling the waste electronics by hand. The components are then separated for recycling and the circuit boards are shredded before being fed into the furnace.

All of the metals, including high quantities of copper, are collected as a sludge. The precious metals are separated and purified, then melted again in the final stage.

The silver obtained at the end of the refining process is of a higher purity than mined silver, according to Heather.

"Mined silver is usually 99.99 per cent pure," Heather said. "By the end of our refining process, it's 99.999 per cent pure."

"It's actually a beautiful silver to work with," she continued. "It has none of the impurities that you sometimes come across. Our refining process is quite consistent."

The metal is mixed with a small amount of copper to create sterling silver, which can then be handcrafted into jewellery using traditional silversmithing techniques.

"That little bit of copper just gives it the strength it needs to make durable jewellery," said Heather.

Her simple designs include cufflinks with rectangular concrete insets, a necklace with stalk-like pendants and rings in various geometric shapes.

"They're very Minimalist," said Heather. "I'm very interested in clean lines and simple shapes, reducing a design down to its absolute necessary elements."

Heather plans to extend her range to include items made from gold reclaimed in a similar way.

In a movie filmed by Dezeen at Design Indaba 2013, the event's founder Ravi Naidoo explained the importance of upcycling in South African design during a tour of Cape Town's Woodstock district – where Heather's studio is based.