APRIL 2009

Panning scrap streams for gold

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The receiving and grading area at Techmet takes in shipments of waste and sorts it for further handling and processing. Techmet pays anywhere from $3 to $120 depending on the type of unit sent in.

Recovering precious metals from electronic scrap and catalytic converters from autos has become more profitable than ever before. That may explain why more and more specialized “niche” recyclers and refiners have sprung up and the sector has really surged over the past several years. Gold, which traded at an average annual price of $264 per ounce in 2000, has been trading near $1,000 per ounce in recent days. Of course, prices fluctuate, but they have been trending steadily upward for gold, silver and the platinum group metals: ruthenium, rhodium, palladium, osmium, iridium and platinum. The obvious reason for the sharp price increases is the economic crisis; for the feeling of security in uncertain times and as a hedge against inflation. Precious metals do not even have to be converted to cash – they are tradable as investment or industrial commodities – gold, silver, platinum, and palladium have an ISO 4217 currency code.


There are scant amounts of precious metals in e-wastes, but more in catalytic converters. When processed in volume by an efficient recycler, though, value begins to add up. The amounts of precious metals alone found in e-wastes do not even begin to pay for the costs of recycling and are subsidized by disposal fees and by other materials recovered in the processes such as copper, plastic, steel and glass.

Precious metals from e-waste

“If you have a typical printed circuit board (PCB) in your hand, maybe 2 percent of the weight is gold. Another 18 to 22 percent would be copper and then you have trace amounts of silver, palladium and things of that nature,” said Bill Rockett, vice president of the M&K Recovery Group in Boston.

M&K is a privately held company with 30-years experience in recovering precious metals from electronic wastes. It operates a 35,000 sq. ft. state-of-the-art processing facility in Boston and a 12,000 sq. ft. collection center in Texas from which e-waste is trucked to Boston. In Boston, M&K uses a chemical refining method to recover gold, silver and platinum group metals from encapsulated and clad materials, and a cyanide strip method for gold-plated scrap products. Both processes are zero-discharge, emission-free and operate under a Massachusetts B4 recycling permit.

While copper is the most common material used to conduct electricity in electronic circuitry, silver and gold are also used in thinly plated forms for better conductivity in high-quality surface-to-surface contacts.

In electronics recycling, the primary sources of precious metals are found in PCBs and integrated circuits (ICs) and vary in yields depending on size and type of the board or chip. The highest yields come from personal computers, laptops and cell phones in the form of motherboards, main boards, video and audio boards, network cards and related PCBs and ICs. Lower value PCBs are found in monitors, amplifiers, DVD players, printers, speakers, VCRs, MP3 players, cameras and the like. These usually contain copper and lead, but in much lower quantities of precious metals than computers.

“In the average personal computer there is, generally speaking, 20 percent copper, 2 percent gold, 1 percent silver and 1 percent palladium. Beyond that there’s iron and plastic content that we recycle,” Rockett stated.

After an electronic unit is manually stripped at M&K, PCBs and ICs and other precious metal-bearing components are set aside. An alligator shearing machine is used to trim off small precious metal-bearing pieces from PCBs such as ICs, fingers, connectors, plugs and pins. The small pieces are sent through M&K’s chemical treatment process where the precious metals drop off the PCB fiberglass substrate and are later cast into bars. M&K holds pool accounts with various bullion dealers and bars of precious metals are sold at the daily spot price.

The stripped PCB fiberglass is collected into 25,000 pound lots and sent out to a smelter where it is burned and scrubbed to remove and recover copper.

Approximately 60 percent of e-waste volume processed by M&K comes from OEMs via take-back programs and the balance from corporate customers and miscellaneous sources, but not much from municipal programs. In certain cases, when a customer wants to dispose of a large quantity of electronic components, M&K will process the materials at a contracted price and return the redeemed precious metals to the customer.

Precious metals from catalytic converters

Slag tapping at Techemet from submerged electric arc furnace removes impurities to refine platinum group metals from ceramic catalyst materials.

Replacing a catalytic converter (CC) is expensive. Depending on the auto’s make and model, an OEM replacement part can cost anywhere from $50 to over $1,500. One muffler shop estimate for a Subaru CC system was for $1,300, not counting installation labor. Aftermarket CC prices are less, usually because they are smaller and contain less of the precious metals used as catalysts, such as platinum, rhodium and palladium.

Depending on the size and type of CC, a repair shop can get $25 to $50 for a used one. Increasingly, auto manufacturers are asking dealers to return used units so they can recycle parts and recover precious metals.

Most scrap recyclers accumulate CCs and send them off in bulk shipments to companies like PMR Catalytic Converter Recycling in Quebec that specializes in recycling CCs. It is the only company of its type in Canada and bills itself as the North American leader in the analysis, cutting and recycling of the metals and ceramics found in all models of catalytic converters. “I buy in Canada and all over the United States, anywhere,” said Pierre Marchend, PMR’s general manager and principal buyer. “On average we pay roughly $45 for each scrap unit and process about 100,000 catalytic converters each month.”

At PMR, the first step is to “decan” or remove the auto catalyst materials from the whole steel converter unit. This involves shearing open the steel or stainless steel case to release the bead or honeycomb ceramic biscuits. Since the recovery value is in the Platinum Group Metals (PGM) that coat the ceramic catalyst material, all the dust and small pieces are collected. The catalyst material is then crushed and milled into a uniform powder. PMR’s powder is then assayed to determine the precious metal content, but this is only a conditional assay, a rough approximation of content that accompanies the material to the next step in recovery.

PMR sends its catalyst powder for refining to Techemet, a technical, chemical and metallurgic group headquartered in Pasadena, Texas and one of the top three companies of its type in the world. From Texas, Techemet directs its international recycling and refining operations in the United Kingdom, continental Europe, Mexico and Central America. Catalytic converters represent approximately 90 percent Techemet’s business, but it also recovers platinum, palladium, rhodium, gold and silver from industrial catalysts used in petroleum and chemical processing as well as from electronic, jewelry and dental scrap.

“At the moment, business is slow. Last year was our best year ever in volume, but it trailed off in November and December, said Stewart Prentice, a Techemet partner. “Currently, everyone in our industry is running about 50 percent of the level of last year. There’s a shortage of catalytic converters, too, because a lot of auto wreckers are not selling. They are stockpiling, waiting for prices to go up.”

Techemet takes in decanned catalysts from companies like PMR. While catalysts represent the majority of Techemet’s business, it also takes in whole converters from scrap dealers. Because there are literally thousands of types of catalytic converters in a range of sizes, Techemet pays anywhere from three dollars to $120 for a whole unit.

To refine catalysts, Techemet uses two submerged electric arc furnaces that have a combined capacity of 20 million pounds of annual feed. Submerged electric arc furnaces are physically different from steel-making furnaces. In submerged arc furnaces the electrode tips are buried in the slag-charge and arcing occurs through the slag between a matte and an electrode. Steelmaking arc furnaces arc in the open and usually operate on a continuous, rather than on a batch basis like a submerged arc furnace.

After the catalyst material is refined in the arc furnace, the extracted metal is called “PGM alloy” and it contains approximately 10 percent precious metals. The remaining ceramic material is of negligible value and is used for road fill. Techemet sends out its PGM alloy to chemical refineries for final processing into 99.99 percent pure platinum, palladium and rhodium sponge. Techemet’s smelter generates no waste streams, nothing that is processed is discarded and everything is recycled.