Innovative practices lead to higher precious metal recovery

Innovative practices lead to higher precious metal recovery

December 10, 2019
Maura Keller

As e-waste continues to flood our waste stream, the improper disposal of electronics – specifically cell phones and computers – is a huge threat to the environment

State-of-the-art electronics are also a treasure trove of precious metals. And while pulling precious metals from these items makes sense financially, it has also resulted in significantly improved environmentally friendly and sustainable recycling technologies.

According to the January 2019 report from the World Economic Forum, in the USA, the recycling rate of e-waste hovers around 25%. The remaining 75% of this waste is stored in numerous places due to a lack of convenient recycling options. But this e-waste is teeming with precious metals, all of which can be recovered and recycled for future use. For instance, in 2015 Apple reported that it had recovered more than a ton of gold from recycled devices, resulting in over US$40 million worth of gold, reducing the need for future mining efforts.

As Meredith Leahy, waste diversion manager and circular solutions lead at Rubicon Global explained, the EPA has published some key numbers on the amount of precious metals we have in our electronics.

“The EPA states that cell phones alone contain gold, silver, platinum, palladium, copper, tin and zinc. Those recovered materials can then be used in items like jewelry, other electronics and even art,” Leahy said.

Recovering precious metals via e-waste recycling is 13 times cheaper than extracting these metals from mines

And while recovering precious metals from electronic waste is an environmentally sound practice, according to research published in the American Chemical Society’s journal, Environmental Science & Technology, it is also fiscally responsible. Recovering precious metals via e-waste recycling is 13 times cheaper than extracting these metals from mines.

The role these metals play in electronics is paramount. Paul Gregory, director of recycling and organics at Texas Disposal Systems (TDS), said these metals are normally used as filaments and critical contact points that conduct electricity throughout electronics. Because of their high value, these are the most important metals to harvest from electronics. Texas Disposal Systems is one of the largest independently owned solid waste collection, processing and disposal companies in the nation. The company’s fully integrated facility incorporates solid waste disposal, compost production and recycling operations.

Of course, there are other key metals such as copper, nickel, and aluminum in casings, wiring and other components of a computer or cell phone. “These non-ferrous metals have a high value as well and are just as recyclable as any other metals,” Gregory said. “Our company will collect and recycle all of these metals mentioned, as well as several other types of metals and recyclables.”

In fact, these valuable metals were some of the metals that TDS harvested in the company’s early days.

“When we handled the disposal of IBM computers in the 1970s, we would recycle and repurpose the metal used from servers, tube components and other large electronic parts. This allowed us to develop our business in sustainability and kick start our recycling efforts more than 40 years ago,” Gregory said.

Methods to take
As Leahy explained, there are two dominant approaches to recycling today’s used electronics – one is de-manufacturing, which is manually dismantling the electronics in order to utilize the raw materials that are found for recycling and the other is shredding, where the electronics are loaded into large shredders which helps to reduce manual sorting and separation of components.

Metals have been recycled for thousands of years, but in the past 50 years or so, we’ve seen some interesting developments, particularly in fields using granulation methods to pull out more metals with less effort

“Metals have been recycled for thousands of years, but in the past 50 years or so, we’ve seen some interesting developments, particularly in fields using granulation methods to pull out more metals with less effort,” Gregory said.

Some newer methods, such as the ones used by Liquisort, will actually process these metals in a special bath. Located in the Netherlands, Liquisort specializes in the separation of non-ferrous metals by using a sustainable, innovated and patented sorting method that makes it possible to sort various metals into clean, separated fractions.

As Gregory explained, “Liquisort’s bath separates metals with dense water and magnet systems to better the purity of metals. This granulation process is a relatively new one, and when combined with shredding options of electronic waste, this reduces the need for hand-separation and increases the amount of metals that we can recycle, particularly from electronic waste.

“After going through several layers of separation and granulation, precious metals will create a fine mesh or powdery-like substance,” Gregory said. This substance will get packed into 55 gallon drums or other containers, then shipped to a smelter or refinery to be melted down to create new metals. Fine meshes and powders will get melted down and even further separated in large furnaces. This process will help separate different metals by quality, such as 18 and 24 carat gold.

After the smelting process, the metals can then be forged into new uses, such as jewelry, new computer parts or other purposes of precious metals.

Currently, TDS does not offer granulation, smelting or refining, but the company cleans and separates raw metal materials to make it as easy as possible for smelters and refiners to create a new product.

The biggest macro trend we’re seeing in the metal recycling business is that smaller items are being built, which means we need to do more work for less product

“The biggest macro trend we’re seeing in the metal recycling business is that smaller items are being built, which means we need to do more work for less product,” Gregory said. “As structural metals are becoming smaller, we’re seeing a sweeping change from industrial and oil field metal waste coming in for metal recycling to more electronic waste. We’re seeing less use of large metal materials in building and manufacturing, but seeing a dramatic increase in cell phones, computers, televisions, monitors and other smaller consumer electronics.”

With these smaller products to harvest metals from, Gregory said it becomes harder to recover materials, especially when it comes to hand separating or using human labor.

“It’s not as effective to recover these small metals by hand, breaking these items with hammers or axes like recyclers did with IBM-sized computers in the 1970s,” Gregory said. “There are more plastic, glass and other non-metal parts you have to get through to harvest the valuable metal commodities.”

The New Zealand clean tech company Mint Innovation has developed a unique biometallurgical method to recover precious metals from electronic waste

Recycling innovations in precious metals recovery from e-waste continue to surprise. For example, the New Zealand clean tech company Mint Innovation has developed a unique biometallurgical method to recover precious metals from electronic waste. Using microorganisms to selectively and quickly recover precious metals, such as gold, Mint Innovation can extract these precious metals from electronic waste.

In 2017, Vancouver-based EnviroLeach Technologies Inc entered into a strategic global partnership with Jabil Inc to utilize EnviroLeach’s patent-pending formula and processes for the recovery of metals from circuit boards and electronic waste in Memphis, Tennessee.

Specifically, EnviroLeach’s cyanide-free and acid-free-based chemical formula operates at ambient temperature and at near-neutral pH. Traditionally, cyanide has been used to extract gold but instead of using cyanide, EnviroLeach’s formula uses five non-toxic, FDA-approved ingredients that are combined with water at ambient temperatures.

In addition to these innovative precious metal recycling technologies, some key trends of precious metal recycling that industry players need to focus on include innovation in bulk shredding processes, in mechanically sorting metals and in emerging parts of the smelters’/refiners’ global market.

In the USA, we don’t see a lot of end result smelting due to environmental regulations, but we’ll see emerging fields like copper in South America or nickel in Germany as consistent buyers of these raw, recycled materials

“In the USA, we don’t see a lot of end result smelting due to environmental regulations, but we’ll see emerging fields like copper in South America or nickel in Germany as consistent buyers of these raw, recycled materials,” Gregory said. “Metal recyclers who can capitalize on e-waste in the future will be the metal recyclers who succeed in this industry. We look forward to leading our industry in sustainable, responsible metal and e-waste commodity recycling.”

This article first appeared on the American Recycler website

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