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Auto dismantlers and auto shredding plant operators face an ongoing series of decisions when it comes to determining which components are worth harvesting from end-of-life vehicles (ELVs) and whether they offer a return on investment when handled separately.

Shifting commodity pricing over the years has determined how aluminum wheels, wiring harnesses and exhaust system components are handled by recyclers. Environmental, health and safety considerations have come into play for some components.

As cars have adopted sophisticated electronics systems, printed circuit boards (PCBs) have offered incentives and disincentives, creating reasons for recyclers to pay additional attention to them. Each circuit board is light in weight, but the sheer number of PCBs per vehicle is growing steadily.

Under the hood

Circuit boards gained prominence in passenger vehicles in a diagnostic role—they came in the form of the “onboard computers” that helped mechanics identify engine problems. The PCB presence in vehicles has spread to nearly every core function or system of a car.

By the 2017 model year, the average car had “50-plus CPUs (central processing units) and more than 100 million lines of code for the various control, entertainment and safety systems,” according to Steve Rogerson, writing for Vehicle Electronics, the online magazine for automotive electronics engineers at https://vehicle-electronics.biz.

The types of PCBs or CPUs used in a car can vary greatly from model to model, but if a board is in working order when a car is salvaged, selling into the aftermarket provides dismantlers with one opportunity. EBay serves as one of many places where a harvested auto- related circuit board can be resold.

Recyclers who don’t wish to pursue this somewhat labor-intensive side business might still want to identify and extract PCBs from ELVs to protect or enhance the value of the secondary commodities they produce.

Pieces of circuit boards found within mixed shredded metals shipped by shredding plant operators are considered contaminants by downstream sorting plants or melting facilities they supply.

Buyers anywhere in the world who see pieces of bright green shredded PCB plastic in mixed metals grades such as zorba, twitch and zurik tend to point out the contaminant. In China, as that nation’s customs and environmental agencies have increased their direct scrutiny of shipments, they have pointed to these fragments as a mark against the shipper.

The other way PCBs can affect an auto recycler’s revenue stream involves the (usually slim) percentage of a PCB that consists of gold or silver. The presence of these precious metals has long been a factor in the way PCBs are handled by recyclers of consumer and office electronics, and the same incentive can apply to automotive PCBs.

Precious for a reason

Silver and gold (along with platinum and palladium) retain their designation as “precious metals” in part because their monetary value is measured by the ounce rather than the pound or ton.

Because of their longtime use in exhaust system components, auto recyclers and shredder operators tend to track the market for palladium and platinum. (See the sidebar, “Diesel sputters, palladium soars,” on page 39 of this issue and the feature “Revved up demand.”)

The exhaust system converters—each of which contains measurable amounts of either palladium or platinum—have developed their own recycling subsector. This status has not yet been achieved for automotive PCBs. Circuit boards still go routinely unrecycled in discarded household and office equipment, suffering a similar fate as many of those found in vehicles.

Mahesh Chander Vats and S.K. Singh of Delhi Technological University published a 2015 article based on their studies on PCB recycling. Vats and Singh estimate that just 15 percent of the gold and silver used in electronic equipment is recovered and recycled, while the rest “lies in storage yards or landfills.”

Extracting the tiny amounts of gold and silver may not be judged worth the effort unless sufficient scale (in the form of a large number of PCBs) is amassed.

The same Indian study used atomic absorption spectroscopy sampling to determine that gold content in PCBs is “in the range of 0.009 to 0.017 percent” by weight, while the silver content weighed in at between 0.25 and 0.79 percent.

Wringing out the value

Considering circuit boards are very lightweight, several thousand PCBs may need to be extracted and aggregated over time to recover an ounce of their precious metals content.

Umicore Precious Metals Recycling, Hoboken, Belgium, seeks PCBs and printed wiring boards for its smelting process, which has been designed to separate and recover the precious metals, copper and base metals found in PCBs. The company’s smelter in Hoboken can make it more feasible to handle PCBs generated in Europe compared with North America, but Umicore markets its services to American recyclers.

Mining the silver from circuit boards is also a business model being pursued by Reno, Nevada-based Itronics Inc. (See page S38 of the 2019 Scrap Metals Supplement that accompanies this issue for a profile on the company.) As of late November 2018, Itronics says it has been procuring a “reliable supply of circuit boards that have been stripped to [its] specifications for processing.”

Itronics plans to feed its PCB refining plant via an alliance with Sparks, Nevada-based New2U Computers “to acquire new and larger recycling contracts with local businesses [to] increase the supply of e-scrap circuit boards to support Itronics’ refining expansion.”

Helpful to any effort to recover silver from PCBs would be lofty pricing for it or the gold contained within. The 2018 market did not provide that incentive, however, with the per-ounce price of silver having drifted downward by 13.7 percent from more than $16.40 per ounce on the London Metal Exchange (LME) in late 2017 to just $14.15 per ounce in late 2018.

Not yet fully determined is how the growing presence of hybrid and electric vehicles (EVs) in the ELV stream may affect the feasibility of recovering PCB precious metals.

Because EVs do not have combustible exhaust that must be treated using catalytic converters, the amount of platinum and palladium in the ELV stream is predicted to shrink if EVs continue to gain market share.

Silver, however, may be a winner in an anticipated EV revolution. The precious metal is used in circuit boards and also in batteries, electrodes and other roles as a conductor. According to a June 2018 article on the Stockhead website out of Australia, https://stockhead.com.au, in 2017 “the auto sector’s demand for silver grew by 5 percent, while silver demand in photovoltaics increased 19 percent.”

Author Angela East adds, “As self-driving vehicles start to become a reality, silver will also have a role to play” because it offers “high electrical conductivity.”

The direction of the ELV sector will cause auto dismantlers and shredding plant operators to keep tabs on precious metals markets and opportunities.

The author is the senior editor with Recycling Today Media Group and can be contacted at btaylor@gie.net.