New e-waste plant will use microbes to recover metals

A processing plant using biotechnology to recover valuable metals from electronic waste is set to be built in Sydney’s western suburbs.

The plant in Smithfield will be operated by Mint Innovation, a New Zealand start-up that recently reached a property deal with the Cumberland City Council.

Mint uses patented bioprocessing technology involving a combination of metallurgy and biometallurgy to extract base and precious metals from discarded print circuit boards (PCBs).

Biometallurgy is a generic term covering the bioleaching, biosorption, and bioaccumulation of metals using microorganisms. 

It is cyanide-free, and the process streams themselves are recycled, providing an environmentally responsible solution for what is a noxious waste stream.

By enabling increasing volumes of electronic waste to be processed in an environmentally responsible manner, Mint says its technology potentially provides greater returns to recyclers.

The company will deal directly with e-waste recyclers to buy crushed and powdered circuit boards, with payments based on metal value recovered. 

According to the UN’s Global E-waste Monitor 2020, 53.6 million tonnes of electronic waste was generated worldwide in 2019. The raw materials in this e-waste were worth around $57 billion – with iron, copper, and gold contributing most to this value.

However, only a sixth of that value ($10 billion) is recovered in an environmentally sound way.  

Mint set up a biometallurgy demonstration plant in NZ in 2019, but Smithfield will be the company’s first commercial foray, opening in 2022. It will process up to 3500 tonnes of electronic waste a year and employ 25-30 people.  

The company plans to build its second commercial biorefinery in Britain.